full_paragraphs:
  A.1.1:
  - Observed Warming and its Causes  Global surface temperature was around 1.1°C above
    1850–1900 in 2011–2020 64, with larger increases over land than over the ocean
    65 . Observed warming is human-caused, with warming from greenhouse gases, dominated
    by CO2 and methane, partly masked by aerosol cooling. Global surface temperature
    in the first two decades of the 21st century was 0.99 [0.84 to 1.10]°C higher
    than 1850–1900. Global surface temperature has increased faster since 1970 than
    in any other 50-year period over at least the last 2000 years. The likely range
    of total human-caused global surface temperature increase from 1850–1900 to 2010–201966
    is 0.8°C to 1.3°C, with a best estimate of 1.07°C. It is likely that well-mixed
    GHGs 67 contributed a warming of 1.0°C to 2.0°C, and other human drivers contributed
    a cooling of 0.0°C to 0.8°C, natural drivers changed global surface temperature
    by ±0.1°C and internal variability changed it by ±0.2°C.  Observed increases in
    well-mixed GHG concentrations since around 1750 are unequivocally caused by GHG
    emissions from human activities. Land and ocean sinks have taken up a near-constant
    proportion of CO2 emissions from human activities over the past six decades, with
    regional differences. In 2019, atmospheric CO2 concentrations reached 410 parts
    per million, CH 4 reached 1866 parts per billion and nitrous oxide reached 332
    ppb. Other major contributors to warming are tropospheric ozone and halogenated
    gases. Concentrations of CH 4 and N2 O have increased to levels unprecedented
    in at least 800, years, and there is high confidence that current CO 2 concentrations
    are higher than at any time over at least the past two million years. Since 1750,
    increases in CO 2 and CH4 concentrations far exceed – and increases in N2 O are
    similar to – the natural multi-millennial changes between glacial and interglacial
    periods over at least the past 800, years. The net cooling effect which arises
    from anthropogenic aerosols peaked in the late 20th century .  Average annual
    GHG emissions during 2010–2019 were higher than in any previous decade, but the
    rate of growth between 2010 and 2019 was lower than that between 2000 and 2009  69
    . Historical cumulative net CO 2 emissions from 1850 to 2019 were 2400 ±240 GtCO2.
    Of these, more than half occurred between 1850 and 1989 [1400 ±195 GtCO 2], and
    about 42% between 1990 and 2019 [1000 ±90 GtCO2]. Global net anthropogenic GHG
    emissions have been estimated to be 59±6.6 GtCO 2 -eq in 2019, about 12% higher
    than in 2010 and 54% higher than in 1990. By 2019, the largest growth in gross
    emissions occurred in CO2 from fossil fuels and industry followed by CH4, whereas
    the highest relative growth occurred in fluorinated gases, starting from low levels
    in 1990.  Regional contributions to global human-caused GHG emissions continue
    to differ widely. Historical contributions of CO2 emissions vary substantially
    across regions in terms of total magnitude, but also in terms of contributions
    to CO 2 -FFI and net CO2 -LULUCF emissions. Variations in regional and national
    per capita emissions partly reflect different development stages, but they also
    vary widely at similar income levels. Average per capita net anthropogenic GHG
    emissions in 2019 ranged from 2.6 tCO 2-eq to 19 tCO 2-eq across regions. Least
    Developed Countries and Small Island Developing States have much lower per capita
    emissions  than the global average, excluding CO2 -LULUCF. Around 48% of the global
    population in 2019 lives in countries emitting on average more than 6 tCO 2-eq
    per capita, 35% of the global population live in countries emitting more than
    9 tCO2 -eq per capita while another 41% live in countries emitting less than 3
    tCO 2 -eq per capita. A substantial share of the population in these low-emitting
    countries lack access to modern energy services.  Net GHG emissions have increased
    since 2010 across all major sectors. In 2019, approximately 34% of net global
    GHG emissions came from the energy sector, 24% from industry, 22% from AFOLU,
    15% from transport and 6% from buildings . Average annual GHG emissions growth
    between 2010 and 2019 slowed compared to the previous decade in energy supply
    and industry but remained roughly constant at about 2% yr –1 in the transport
    sector . About half of total net AFOLU emissions are from CO2 LULUCF, predominantly
    from deforestation. Land overall constituted a net sink of –6.6 GtCO 2 yr–1 for
    the period 2010–201972.  Human-caused climate change is a consequence of more
    than a century of net GHG emissions from energy use, land-use and land use change,
    lifestyle and patterns of consumption, and production. Emissions reductions in
    CO2 from fossil fuels and industrial processes, due to improvements in energy
    intensity of GDP and carbon intensity of energy, have been less than emissions
    increases from rising global activity levels in industry, energy supply, transport,
    agriculture and buildings. The 10% of households with the highest per capita emissions
    contribute 34–45% of global consumption-based household GHG emissions, while the
    middle 40% contribute 40–53%, and the bottom 50% contribute 13–15%. An increasing
    share of emissions can be attributed to urban areas . The drivers of urban GHG
    emissions 73 are complex and include population size, income, state of urbanisation
    and urban form.
  A.1.3:
  - Observed Warming and its Causes  Global surface temperature was around 1.1°C above
    1850–1900 in 2011–2020 64, with larger increases over land than over the ocean
    65 . Observed warming is human-caused, with warming from greenhouse gases, dominated
    by CO2 and methane, partly masked by aerosol cooling. Global surface temperature
    in the first two decades of the 21st century was 0.99 [0.84 to 1.10]°C higher
    than 1850–1900. Global surface temperature has increased faster since 1970 than
    in any other 50-year period over at least the last 2000 years. The likely range
    of total human-caused global surface temperature increase from 1850–1900 to 2010–201966
    is 0.8°C to 1.3°C, with a best estimate of 1.07°C. It is likely that well-mixed
    GHGs 67 contributed a warming of 1.0°C to 2.0°C, and other human drivers contributed
    a cooling of 0.0°C to 0.8°C, natural drivers changed global surface temperature
    by ±0.1°C and internal variability changed it by ±0.2°C.  Observed increases in
    well-mixed GHG concentrations since around 1750 are unequivocally caused by GHG
    emissions from human activities. Land and ocean sinks have taken up a near-constant
    proportion of CO2 emissions from human activities over the past six decades, with
    regional differences. In 2019, atmospheric CO2 concentrations reached 410 parts
    per million, CH 4 reached 1866 parts per billion and nitrous oxide reached 332
    ppb. Other major contributors to warming are tropospheric ozone and halogenated
    gases. Concentrations of CH 4 and N2 O have increased to levels unprecedented
    in at least 800, years, and there is high confidence that current CO 2 concentrations
    are higher than at any time over at least the past two million years. Since 1750,
    increases in CO 2 and CH4 concentrations far exceed – and increases in N2 O are
    similar to – the natural multi-millennial changes between glacial and interglacial
    periods over at least the past 800, years. The net cooling effect which arises
    from anthropogenic aerosols peaked in the late 20th century .  Average annual
    GHG emissions during 2010–2019 were higher than in any previous decade, but the
    rate of growth between 2010 and 2019 was lower than that between 2000 and 2009  69
    . Historical cumulative net CO 2 emissions from 1850 to 2019 were 2400 ±240 GtCO2.
    Of these, more than half occurred between 1850 and 1989 [1400 ±195 GtCO 2], and
    about 42% between 1990 and 2019 [1000 ±90 GtCO2]. Global net anthropogenic GHG
    emissions have been estimated to be 59±6.6 GtCO 2 -eq in 2019, about 12% higher
    than in 2010 and 54% higher than in 1990. By 2019, the largest growth in gross
    emissions occurred in CO2 from fossil fuels and industry followed by CH4, whereas
    the highest relative growth occurred in fluorinated gases, starting from low levels
    in 1990.  Regional contributions to global human-caused GHG emissions continue
    to differ widely. Historical contributions of CO2 emissions vary substantially
    across regions in terms of total magnitude, but also in terms of contributions
    to CO 2 -FFI and net CO2 -LULUCF emissions. Variations in regional and national
    per capita emissions partly reflect different development stages, but they also
    vary widely at similar income levels. Average per capita net anthropogenic GHG
    emissions in 2019 ranged from 2.6 tCO 2-eq to 19 tCO 2-eq across regions. Least
    Developed Countries and Small Island Developing States have much lower per capita
    emissions  than the global average, excluding CO2 -LULUCF. Around 48% of the global
    population in 2019 lives in countries emitting on average more than 6 tCO 2-eq
    per capita, 35% of the global population live in countries emitting more than
    9 tCO2 -eq per capita while another 41% live in countries emitting less than 3
    tCO 2 -eq per capita. A substantial share of the population in these low-emitting
    countries lack access to modern energy services.  Net GHG emissions have increased
    since 2010 across all major sectors. In 2019, approximately 34% of net global
    GHG emissions came from the energy sector, 24% from industry, 22% from AFOLU,
    15% from transport and 6% from buildings . Average annual GHG emissions growth
    between 2010 and 2019 slowed compared to the previous decade in energy supply
    and industry but remained roughly constant at about 2% yr –1 in the transport
    sector . About half of total net AFOLU emissions are from CO2 LULUCF, predominantly
    from deforestation. Land overall constituted a net sink of –6.6 GtCO 2 yr–1 for
    the period 2010–201972.  Human-caused climate change is a consequence of more
    than a century of net GHG emissions from energy use, land-use and land use change,
    lifestyle and patterns of consumption, and production. Emissions reductions in
    CO2 from fossil fuels and industrial processes, due to improvements in energy
    intensity of GDP and carbon intensity of energy, have been less than emissions
    increases from rising global activity levels in industry, energy supply, transport,
    agriculture and buildings. The 10% of households with the highest per capita emissions
    contribute 34–45% of global consumption-based household GHG emissions, while the
    middle 40% contribute 40–53%, and the bottom 50% contribute 13–15%. An increasing
    share of emissions can be attributed to urban areas . The drivers of urban GHG
    emissions 73 are complex and include population size, income, state of urbanisation
    and urban form.
  A.1.5:
  - Observed Warming and its Causes  Global surface temperature was around 1.1°C above
    1850–1900 in 2011–2020 64, with larger increases over land than over the ocean
    65 . Observed warming is human-caused, with warming from greenhouse gases, dominated
    by CO2 and methane, partly masked by aerosol cooling. Global surface temperature
    in the first two decades of the 21st century was 0.99 [0.84 to 1.10]°C higher
    than 1850–1900. Global surface temperature has increased faster since 1970 than
    in any other 50-year period over at least the last 2000 years. The likely range
    of total human-caused global surface temperature increase from 1850–1900 to 2010–201966
    is 0.8°C to 1.3°C, with a best estimate of 1.07°C. It is likely that well-mixed
    GHGs 67 contributed a warming of 1.0°C to 2.0°C, and other human drivers contributed
    a cooling of 0.0°C to 0.8°C, natural drivers changed global surface temperature
    by ±0.1°C and internal variability changed it by ±0.2°C.  Observed increases in
    well-mixed GHG concentrations since around 1750 are unequivocally caused by GHG
    emissions from human activities. Land and ocean sinks have taken up a near-constant
    proportion of CO2 emissions from human activities over the past six decades, with
    regional differences. In 2019, atmospheric CO2 concentrations reached 410 parts
    per million, CH 4 reached 1866 parts per billion and nitrous oxide reached 332
    ppb. Other major contributors to warming are tropospheric ozone and halogenated
    gases. Concentrations of CH 4 and N2 O have increased to levels unprecedented
    in at least 800, years, and there is high confidence that current CO 2 concentrations
    are higher than at any time over at least the past two million years. Since 1750,
    increases in CO 2 and CH4 concentrations far exceed – and increases in N2 O are
    similar to – the natural multi-millennial changes between glacial and interglacial
    periods over at least the past 800, years. The net cooling effect which arises
    from anthropogenic aerosols peaked in the late 20th century .  Average annual
    GHG emissions during 2010–2019 were higher than in any previous decade, but the
    rate of growth between 2010 and 2019 was lower than that between 2000 and 2009  69
    . Historical cumulative net CO 2 emissions from 1850 to 2019 were 2400 ±240 GtCO2.
    Of these, more than half occurred between 1850 and 1989 [1400 ±195 GtCO 2], and
    about 42% between 1990 and 2019 [1000 ±90 GtCO2]. Global net anthropogenic GHG
    emissions have been estimated to be 59±6.6 GtCO 2 -eq in 2019, about 12% higher
    than in 2010 and 54% higher than in 1990. By 2019, the largest growth in gross
    emissions occurred in CO2 from fossil fuels and industry followed by CH4, whereas
    the highest relative growth occurred in fluorinated gases, starting from low levels
    in 1990.  Regional contributions to global human-caused GHG emissions continue
    to differ widely. Historical contributions of CO2 emissions vary substantially
    across regions in terms of total magnitude, but also in terms of contributions
    to CO 2 -FFI and net CO2 -LULUCF emissions. Variations in regional and national
    per capita emissions partly reflect different development stages, but they also
    vary widely at similar income levels. Average per capita net anthropogenic GHG
    emissions in 2019 ranged from 2.6 tCO 2-eq to 19 tCO 2-eq across regions. Least
    Developed Countries and Small Island Developing States have much lower per capita
    emissions  than the global average, excluding CO2 -LULUCF. Around 48% of the global
    population in 2019 lives in countries emitting on average more than 6 tCO 2-eq
    per capita, 35% of the global population live in countries emitting more than
    9 tCO2 -eq per capita while another 41% live in countries emitting less than 3
    tCO 2 -eq per capita. A substantial share of the population in these low-emitting
    countries lack access to modern energy services.  Net GHG emissions have increased
    since 2010 across all major sectors. In 2019, approximately 34% of net global
    GHG emissions came from the energy sector, 24% from industry, 22% from AFOLU,
    15% from transport and 6% from buildings . Average annual GHG emissions growth
    between 2010 and 2019 slowed compared to the previous decade in energy supply
    and industry but remained roughly constant at about 2% yr –1 in the transport
    sector . About half of total net AFOLU emissions are from CO2 LULUCF, predominantly
    from deforestation. Land overall constituted a net sink of –6.6 GtCO 2 yr–1 for
    the period 2010–201972.  Human-caused climate change is a consequence of more
    than a century of net GHG emissions from energy use, land-use and land use change,
    lifestyle and patterns of consumption, and production. Emissions reductions in
    CO2 from fossil fuels and industrial processes, due to improvements in energy
    intensity of GDP and carbon intensity of energy, have been less than emissions
    increases from rising global activity levels in industry, energy supply, transport,
    agriculture and buildings. The 10% of households with the highest per capita emissions
    contribute 34–45% of global consumption-based household GHG emissions, while the
    middle 40% contribute 40–53%, and the bottom 50% contribute 13–15%. An increasing
    share of emissions can be attributed to urban areas . The drivers of urban GHG
    emissions 73 are complex and include population size, income, state of urbanisation
    and urban form.
  A.2.1:
  - Observed Climate System Changes and Impacts to  Date It is unequivocal that human
    influence has warmed the atmosphere, ocean and land. Widespread and rapid changes
    in the atmosphere, ocean, cryosphere and biosphere have occurred . The scale of
    recent changes across the climate system as a whole and the present state of many
    aspects of the climate system are unprecedented over many centuries to many thousands
    of years. It is very likely that GHG emissions were the main driver of tropospheric
    warming and extremely likely that human-caused stratospheric ozone depletion was
    the main driver of stratospheric cooling between 1979 and the mid-1990s. It is
    virtually certain that the global upper ocean has warmed since the 1970s and extremely
    likely that human influence is the main driver. Ocean warming accounted for 91%
    of the heating in the climate system, with land warming, ice loss and atmospheric
    warming accounting for about 5%, 3% and 1%, respectively. Global mean sea level
    increased by 0.20 [0.15 to 0.25] m between 1901 and 2018. The average rate of
    sea level rise was 1.3 [0.6 to 2.1]mm yr-1 between 1901 and 1971, increasing to
    1.9 [0.8 to 2.9] mm yr-1 between 1971 and 2006, and further increasing to 3.7
    [3.2 to –4.2] mm yr -1 between 2006 and 2018. Human influence was very likely
    the main driver of these increases since at least 1971. Human influence is very
    likely the main driver of the global retreat of glaciers since the 1990s and the
    decrease in Arctic sea ice area between 1979–1988 and 2010–2019. Human influence
    has also very likely contributed to decreased Northern Hemisphere spring snow
    cover and surface melting of the Greenland ice sheet. It is virtually certain
    that human-caused CO2 emissions are the main driver of current global acidification
    of the surface open ocean.  Human-caused climate change is already affecting many
    weather and climate extremes in every region across the globe. Evidence of observed
    changes in extremes such as heatwaves, heavy precipitation, droughts, and tropical
    cyclones, and, in particular, their attribution to human influence, has strengthened
    since AR5. It is virtually certain that hot extremes have become more frequent
    and more intense across most land regions since the 1950s, while cold extremes
    have become less frequent and less severe, with high confidence that human-caused
    climate change is the main driver of these changes. Marine heatwaves have approximately
    doubled in frequency since the 1980s, and human influence has very likely contributed
    to most of them since at least 2006. The frequency and intensity of heavy precipitation
    events have increased since the 1950s over most land areas for which observational
    data are sufficient for trend analysis, and human-caused climate change is likely
    the main driver. Human-caused climate change has contributed to increases in agricultural
    and ecological droughts in some regions due to increased land evapotranspiration
    . It is likely that the global proportion of major tropical cyclone occurrence
    has increased over the last four decades.  Climate change has caused substantial
    damages, and increasingly irreversible losses, in terrestrial, freshwater, cryospheric
    and coastal and open ocean ecosystems. The extent and magnitude of climate change
    impacts are larger than estimated in previous assessments. Approximately half
    of the species assessed globally have shifted polewards or, on land, also to higher
    elevations. Biological responses including changes in geographic placement and
    shifting seasonal timing are often not sufficient to cope with recent climate
    change. Hundreds of local losses of species have been driven by increases in the
    magnitude of heat extremes and mass mortality events on land and in the ocean.
    Impacts on some ecosystems are approaching irreversibility such as the impacts
    of hydrological changes resulting from the retreat of glaciers, or the changes
    in some mountain and Arctic ecosystems driven by permafrost thaw. Impacts in ecosystems
    from slow-onset processes such as ocean acidification, sea level rise or regional
    decreases in precipitation have also been attributed to human-caused climate change.
    Climate change has contributed to desertification and exacerbated land degradation,
    particularly in low lying coastal areas, river deltas, drylands and in permafrost
    areas. Nearly 50% of coastal wetlands have been lost over the last 100 years,
    as a result of the combined effects of localised human pressures, sea level rise,
    warming and extreme climate events.  Climate change has reduced food security
    and affected water security due to warming, changing precipitation patterns, reduction
    and loss of cryospheric elements, and greater frequency and intensity of climatic
    extremes, thereby hindering efforts to meet Sustainable Development Goals. Although
    overall agricultural productivity has increased, climate change has slowed this
    growth in agricultural productivity over the past 50 years globally , with related
    negative crop yield impacts mainly recorded in mid- and low latitude regions,
    and some positive impacts in some high latitude regions. Ocean warming in the
    20th century and beyond has contributed to an overall decrease in maximum catch
    potential, compounding the impacts from overfishing for some fish stocks. Ocean
    warming and ocean acidification have adversely affected food production from shellfish
    aquaculture and fisheries in some oceanic regions . Current levels of global warming
    are associated with moderate risks from increased dryland water scarcity. Roughly
    half of the world’s population currently experiences severe water scarcity for
    at least some part of the year due to a combination of climatic and non-climatic
    drivers. Unsustainable agricultural expansion, driven in part by unbalanced diets
    , increases ecosystem and human vulnerability and leads to competition for land
    and/or water resources. Increasing weather and climate extreme events have exposed
    millions of people to acute food insecurity and reduced water security, with the
    largest impacts observed in many locations and/or communities in Africa, Asia,
    Central and South America, LDCs, Small Islands and the Arctic, and for small-scale
    food producers, low-income households and Indigenous Peoples globally.  In urban
    settings, climate change has caused adverse impacts on human health, livelihoods
    and key infrastructure. Hot extremes including heatwaves have intensified in cities
    , where they have also worsened air pollution events and limited functioning of
    key infrastructure . Urban infrastructure, including transportation, water, sanitation
    and energy systems have been compromised by extreme and slow-onset events , with
    resulting economic losses, disruptions of services and impacts to well-being.
    Observed impacts are concentrated amongst economically and socially marginalised
    urban residents, e.g., those living in informal settlements. Cities intensify
    human-caused warming locally, while urbanisation also increases mean and heavy
    precipitation over and/or downwind of cities and resulting runoff intensity .  Climate
    change has adversely affected human physical health globally and mental health
    in assessed regions, and is contributing to humanitarian crises where climate
    hazards interact with high vulnerability. In all regions increases in extreme
    heat events have resulted in human mortality and morbidity . The occurrence of
    climate-related food-borne and water-borne diseases has increased. The incidence
    of vector-borne diseases has increased from range expansion and/or increased reproduction
    of disease vectors. Animal and human diseases, including zoonoses, are emerging
    in new areas . In assessed regions, some mental health challenges are associated
    with increasing temperatures, trauma from extreme events, and loss of livelihoods
    and culture . Climate change impacts on health are mediated through natural and
    human systems, including economic and social conditions and disruptions. Climate
    and weather extremes are increasingly driving displacement in Africa, Asia, North
    America, and Central and South America , with small island states in the Caribbean
    and South Pacific being disproportionately affected relative to their small population
    size. Through displacement and involuntary migration from extreme weather and
    climate events, climate change has generated and perpetuated vulnerability .  Human
    influence has likely increased the chance of compound extreme events since the
    1950s. Concurrent and repeated climate hazards have occurred in all regions, increasing
    impacts and risks to health, ecosystems, infrastructure, livelihoods and food
    . Compound extreme events include increases in the frequency of concurrent heatwaves
    and droughts; fire weather in some regions; and compound flooding in some locations.
    Multiple risks interact, generating new sources of vulnerability to climate hazards,
    and compounding overall risk. Compound climate hazards can overwhelm adaptive
    capacity and substantially increase damage ).  Economic impacts attributable to
    climate change are increasingly affecting peoples’ livelihoods and are causing
    economic and societal impacts across national boundaries. Economic damages from
    climate change have been detected in climate-exposed sectors, with regional effects
    to agriculture, forestry, fishery, energy, and tourism, and through outdoor labour
    productivity with some exceptions of positive impacts in regions with low energy
    demand and comparative advantages in agricultural markets and tourism. Individual
    livelihoods have been affected through changes in agricultural productivity, impacts
    on human health and food security, destruction of homes and infrastructure, and
    loss of property and income, with adverse effects on gender and social equity
    . Tropical cyclones have reduced economic growth in the short-term. Event attribution
    studies and physical understanding indicate that human-caused climate change increases
    heavy precipitation associated with tropical cyclones. Wildfires in many regions
    have affected built assets, economic activity, and health. In cities and settlements,
    climate impacts to key infrastructure are leading to losses and damages across
    water and food systems, and affect economic activity, with impacts extending beyond
    the area directly impacted by the climate hazard.  Climate change has caused widespread
    adverse impacts and related losses and damages to nature and people . Losses and
    damages are unequally distributed across systems, regions and sectors. Cultural
    losses, related to tangible and intangible heritage, threaten adaptive capacity
    and may result in irrevocable losses of sense of belonging, valued cultural practices,
    identity and home, particularly for Indigenous Peoples and those more directly
    reliant on the environment for subsistence. For example, changes in snow cover,
    lake and river ice, and permafrost in many Arctic regions, are harming the livelihoods
    and cultural identity of Arctic residents including Indigenous populations. Infrastructure,
    including transportation, water, sanitation and energy systems have been compromised
    by extreme and slow-onset events, with resulting economic losses, disruptions
    of services and impacts to well-being.  Across sectors and regions, the most vulnerable
    people and systems have been disproportionately affected by the impacts of climate
    change. LDCs and SIDS who have much lower per capita emissions than the global
    average excluding CO2-LULUCF, also have high vulnerability to climatic hazards,
    with global hotspots of high human vulnerability observed in West-, Central- and
    East Africa, South Asia, Central and South America, SIDS and the Arctic. Regions
    and people with considerable development constraints have high vulnerability to
    climatic hazards. Vulnerability is higher in locations with poverty, governance
    challenges and limited access to basic services and resources, violent conflict
    and high levels of climate-sensitive livelihoods  . Vulnerability at different
    spatial levels is exacerbated by inequity and marginalisation linked to gender,
    ethnicity, low income or combinations thereof, especially for many Indigenous
    Peoples and local communities. Approximately 3.3 to 3.6 billion people live in
    contexts that are highly vulnerable to climate change. Between 2010 and 2020,
    human mortality from floods, droughts and storms was 15 times higher in highly
    vulnerable regions, compared to regions with very low vulnerability. In the Arctic
    and in some high mountain regions, negative impacts of cryosphere change have
    been especially felt among Indigenous Peoples. Human and ecosystem vulnerability
    are interdependent. Vulnerability of ecosystems and people to climate change differs
    substantially among and within regions, driven by patterns of intersecting socio-economic
    development, unsustainable ocean and land use, inequity, marginalisation, historical
    and ongoing patterns of inequity such as colonialism, and governance.
  A.2.2:
  - Observed Climate System Changes and Impacts to  Date It is unequivocal that human
    influence has warmed the atmosphere, ocean and land. Widespread and rapid changes
    in the atmosphere, ocean, cryosphere and biosphere have occurred . The scale of
    recent changes across the climate system as a whole and the present state of many
    aspects of the climate system are unprecedented over many centuries to many thousands
    of years. It is very likely that GHG emissions were the main driver of tropospheric
    warming and extremely likely that human-caused stratospheric ozone depletion was
    the main driver of stratospheric cooling between 1979 and the mid-1990s. It is
    virtually certain that the global upper ocean has warmed since the 1970s and extremely
    likely that human influence is the main driver. Ocean warming accounted for 91%
    of the heating in the climate system, with land warming, ice loss and atmospheric
    warming accounting for about 5%, 3% and 1%, respectively. Global mean sea level
    increased by 0.20 [0.15 to 0.25] m between 1901 and 2018. The average rate of
    sea level rise was 1.3 [0.6 to 2.1]mm yr-1 between 1901 and 1971, increasing to
    1.9 [0.8 to 2.9] mm yr-1 between 1971 and 2006, and further increasing to 3.7
    [3.2 to –4.2] mm yr -1 between 2006 and 2018. Human influence was very likely
    the main driver of these increases since at least 1971. Human influence is very
    likely the main driver of the global retreat of glaciers since the 1990s and the
    decrease in Arctic sea ice area between 1979–1988 and 2010–2019. Human influence
    has also very likely contributed to decreased Northern Hemisphere spring snow
    cover and surface melting of the Greenland ice sheet. It is virtually certain
    that human-caused CO2 emissions are the main driver of current global acidification
    of the surface open ocean.  Human-caused climate change is already affecting many
    weather and climate extremes in every region across the globe. Evidence of observed
    changes in extremes such as heatwaves, heavy precipitation, droughts, and tropical
    cyclones, and, in particular, their attribution to human influence, has strengthened
    since AR5. It is virtually certain that hot extremes have become more frequent
    and more intense across most land regions since the 1950s, while cold extremes
    have become less frequent and less severe, with high confidence that human-caused
    climate change is the main driver of these changes. Marine heatwaves have approximately
    doubled in frequency since the 1980s, and human influence has very likely contributed
    to most of them since at least 2006. The frequency and intensity of heavy precipitation
    events have increased since the 1950s over most land areas for which observational
    data are sufficient for trend analysis, and human-caused climate change is likely
    the main driver. Human-caused climate change has contributed to increases in agricultural
    and ecological droughts in some regions due to increased land evapotranspiration
    . It is likely that the global proportion of major tropical cyclone occurrence
    has increased over the last four decades.  Climate change has caused substantial
    damages, and increasingly irreversible losses, in terrestrial, freshwater, cryospheric
    and coastal and open ocean ecosystems. The extent and magnitude of climate change
    impacts are larger than estimated in previous assessments. Approximately half
    of the species assessed globally have shifted polewards or, on land, also to higher
    elevations. Biological responses including changes in geographic placement and
    shifting seasonal timing are often not sufficient to cope with recent climate
    change. Hundreds of local losses of species have been driven by increases in the
    magnitude of heat extremes and mass mortality events on land and in the ocean.
    Impacts on some ecosystems are approaching irreversibility such as the impacts
    of hydrological changes resulting from the retreat of glaciers, or the changes
    in some mountain and Arctic ecosystems driven by permafrost thaw. Impacts in ecosystems
    from slow-onset processes such as ocean acidification, sea level rise or regional
    decreases in precipitation have also been attributed to human-caused climate change.
    Climate change has contributed to desertification and exacerbated land degradation,
    particularly in low lying coastal areas, river deltas, drylands and in permafrost
    areas. Nearly 50% of coastal wetlands have been lost over the last 100 years,
    as a result of the combined effects of localised human pressures, sea level rise,
    warming and extreme climate events.  Climate change has reduced food security
    and affected water security due to warming, changing precipitation patterns, reduction
    and loss of cryospheric elements, and greater frequency and intensity of climatic
    extremes, thereby hindering efforts to meet Sustainable Development Goals. Although
    overall agricultural productivity has increased, climate change has slowed this
    growth in agricultural productivity over the past 50 years globally , with related
    negative crop yield impacts mainly recorded in mid- and low latitude regions,
    and some positive impacts in some high latitude regions. Ocean warming in the
    20th century and beyond has contributed to an overall decrease in maximum catch
    potential, compounding the impacts from overfishing for some fish stocks. Ocean
    warming and ocean acidification have adversely affected food production from shellfish
    aquaculture and fisheries in some oceanic regions . Current levels of global warming
    are associated with moderate risks from increased dryland water scarcity. Roughly
    half of the world’s population currently experiences severe water scarcity for
    at least some part of the year due to a combination of climatic and non-climatic
    drivers. Unsustainable agricultural expansion, driven in part by unbalanced diets
    , increases ecosystem and human vulnerability and leads to competition for land
    and/or water resources. Increasing weather and climate extreme events have exposed
    millions of people to acute food insecurity and reduced water security, with the
    largest impacts observed in many locations and/or communities in Africa, Asia,
    Central and South America, LDCs, Small Islands and the Arctic, and for small-scale
    food producers, low-income households and Indigenous Peoples globally.  In urban
    settings, climate change has caused adverse impacts on human health, livelihoods
    and key infrastructure. Hot extremes including heatwaves have intensified in cities
    , where they have also worsened air pollution events and limited functioning of
    key infrastructure . Urban infrastructure, including transportation, water, sanitation
    and energy systems have been compromised by extreme and slow-onset events , with
    resulting economic losses, disruptions of services and impacts to well-being.
    Observed impacts are concentrated amongst economically and socially marginalised
    urban residents, e.g., those living in informal settlements. Cities intensify
    human-caused warming locally, while urbanisation also increases mean and heavy
    precipitation over and/or downwind of cities and resulting runoff intensity .  Climate
    change has adversely affected human physical health globally and mental health
    in assessed regions, and is contributing to humanitarian crises where climate
    hazards interact with high vulnerability. In all regions increases in extreme
    heat events have resulted in human mortality and morbidity . The occurrence of
    climate-related food-borne and water-borne diseases has increased. The incidence
    of vector-borne diseases has increased from range expansion and/or increased reproduction
    of disease vectors. Animal and human diseases, including zoonoses, are emerging
    in new areas . In assessed regions, some mental health challenges are associated
    with increasing temperatures, trauma from extreme events, and loss of livelihoods
    and culture . Climate change impacts on health are mediated through natural and
    human systems, including economic and social conditions and disruptions. Climate
    and weather extremes are increasingly driving displacement in Africa, Asia, North
    America, and Central and South America , with small island states in the Caribbean
    and South Pacific being disproportionately affected relative to their small population
    size. Through displacement and involuntary migration from extreme weather and
    climate events, climate change has generated and perpetuated vulnerability .  Human
    influence has likely increased the chance of compound extreme events since the
    1950s. Concurrent and repeated climate hazards have occurred in all regions, increasing
    impacts and risks to health, ecosystems, infrastructure, livelihoods and food
    . Compound extreme events include increases in the frequency of concurrent heatwaves
    and droughts; fire weather in some regions; and compound flooding in some locations.
    Multiple risks interact, generating new sources of vulnerability to climate hazards,
    and compounding overall risk. Compound climate hazards can overwhelm adaptive
    capacity and substantially increase damage ).  Economic impacts attributable to
    climate change are increasingly affecting peoples’ livelihoods and are causing
    economic and societal impacts across national boundaries. Economic damages from
    climate change have been detected in climate-exposed sectors, with regional effects
    to agriculture, forestry, fishery, energy, and tourism, and through outdoor labour
    productivity with some exceptions of positive impacts in regions with low energy
    demand and comparative advantages in agricultural markets and tourism. Individual
    livelihoods have been affected through changes in agricultural productivity, impacts
    on human health and food security, destruction of homes and infrastructure, and
    loss of property and income, with adverse effects on gender and social equity
    . Tropical cyclones have reduced economic growth in the short-term. Event attribution
    studies and physical understanding indicate that human-caused climate change increases
    heavy precipitation associated with tropical cyclones. Wildfires in many regions
    have affected built assets, economic activity, and health. In cities and settlements,
    climate impacts to key infrastructure are leading to losses and damages across
    water and food systems, and affect economic activity, with impacts extending beyond
    the area directly impacted by the climate hazard.  Climate change has caused widespread
    adverse impacts and related losses and damages to nature and people . Losses and
    damages are unequally distributed across systems, regions and sectors. Cultural
    losses, related to tangible and intangible heritage, threaten adaptive capacity
    and may result in irrevocable losses of sense of belonging, valued cultural practices,
    identity and home, particularly for Indigenous Peoples and those more directly
    reliant on the environment for subsistence. For example, changes in snow cover,
    lake and river ice, and permafrost in many Arctic regions, are harming the livelihoods
    and cultural identity of Arctic residents including Indigenous populations. Infrastructure,
    including transportation, water, sanitation and energy systems have been compromised
    by extreme and slow-onset events, with resulting economic losses, disruptions
    of services and impacts to well-being.  Across sectors and regions, the most vulnerable
    people and systems have been disproportionately affected by the impacts of climate
    change. LDCs and SIDS who have much lower per capita emissions than the global
    average excluding CO2-LULUCF, also have high vulnerability to climatic hazards,
    with global hotspots of high human vulnerability observed in West-, Central- and
    East Africa, South Asia, Central and South America, SIDS and the Arctic. Regions
    and people with considerable development constraints have high vulnerability to
    climatic hazards. Vulnerability is higher in locations with poverty, governance
    challenges and limited access to basic services and resources, violent conflict
    and high levels of climate-sensitive livelihoods  . Vulnerability at different
    spatial levels is exacerbated by inequity and marginalisation linked to gender,
    ethnicity, low income or combinations thereof, especially for many Indigenous
    Peoples and local communities. Approximately 3.3 to 3.6 billion people live in
    contexts that are highly vulnerable to climate change. Between 2010 and 2020,
    human mortality from floods, droughts and storms was 15 times higher in highly
    vulnerable regions, compared to regions with very low vulnerability. In the Arctic
    and in some high mountain regions, negative impacts of cryosphere change have
    been especially felt among Indigenous Peoples. Human and ecosystem vulnerability
    are interdependent. Vulnerability of ecosystems and people to climate change differs
    substantially among and within regions, driven by patterns of intersecting socio-economic
    development, unsustainable ocean and land use, inequity, marginalisation, historical
    and ongoing patterns of inequity such as colonialism, and governance.
  - Equity and Inclusion in Climate Change Action  Actions that prioritise equity,
    climate justice, social justice and inclusion lead to more sustainable outcomes,
    co-benefits, reduce trade-offs, support transformative change and advance climate
    resilient development. Adaptation responses are immediately needed to reduce rising
    climate risks, especially for the most vulnerable. Equity, inclusion and just
    transitions are key to progress on adaptation and deeper societal ambitions for
    accelerated mitigation. Adaptation and mitigation actions, across scales, sectors
    and regions, that prioritise equity, climate justice, rights-based approaches,
    social justice and inclusivity, lead to more sustainable outcomes, reduce trade-offs,
    support transformative change and advance climate resilient development . Redistributive
    policies across sectors and regions that shield the poor and vulnerable, social
    safety nets, equity, inclusion and just transitions, at all scales can enable
    deeper societal ambitions and resolve trade-offs with sustainable development
    goals., particularly education, hunger, poverty, gender and energy access . Mitigation
    efforts embedded within the wider development context can increase the pace, depth
    and breadth of emission reductions . Equity, inclusion and just transitions at
    all scales enable deeper societal ambitions for accelerated mitigation, and climate
    action more broadly. The complexity in risk of rising food prices, reduced household
    incomes, and health and climate-related malnutrition  and mortality increases
    with little or low levels of adaptation.  Regions and people with considerable
    development constraints have high vulnerability to climatic hazards. Adaptation
    outcomes for the most vulnerable within and across countries and regions are enhanced
    through approaches focusing on equity, inclusivity, and rights-based approaches,
    including 3.3 to 3.6 billion people living in contexts that are highly vulnerable
    to climate change. Vulnerability is higher in locations with poverty, governance
    challenges and limited access to basic services and resources, violent conflict
    and high levels of climate-sensitive livelihoods  . Several risks can be moderated
    with adaptation. The largest adaptation gaps exist among lower income population
    groups and adaptation progress is unevenly distributed with observed adaptation
    gaps. Present development challenges causing high vulnerability are influenced
    by historical and ongoing patterns of inequity such as colonialism, especially
    for many Indigenous Peoples and local communities. Vulnerability is exacerbated
    by inequity and marginalisation linked to gender, ethnicity, low income or combinations
    thereof, especially for many Indigenous Peoples and local communities.  Meaningful
    participation and inclusive planning, informed by cultural values, Indigenous
    Knowledge, local knowledge, and scientific knowledge can help address adaptation
    gaps and avoid maladaptation. Such actions with flexible pathways may encourage
    low-regret and timely actions . Integrating climate adaptation into social protection
    programmes, including cash transfers and public works programmes, would increase
    resilience to climate change, especially when supported by basic services and
    infrastructure.  Equity, inclusion, just transitions, broad and meaningful participation
    of all relevant actors in decision making at all scales enable deeper societal
    ambitions for accelerated mitigation, and climate action more broadly, and build
    social trust, support transformative changes and an equitable sharing of benefits
    and burdens. Equity remains a central element in the UN climate regime, notwithstanding
    shifts in differentiation between states over time and challenges in assessing
    fair shares. Ambitious mitigation pathways imply large and sometimes disruptive
    changes in economic structure, with significant distributional consequences, within
    and between countries, including shifting of income and employment during the
    transition from high to low emissions activities. While some jobs may be lost,
    low-emissions development can also open up opportunities to enhance skills and
    create jobs. Broadening equitable access to finance, technologies and governance
    that facilitate mitigation, and consideration of climate justice can help equitable
    sharing of benefits and burdens, especially for vulnerable countries and communities.  Development
    priorities among countries also reflect different starting points and contexts,
    and enabling conditions for shifting development pathways towards increased sustainability
    will therefore differ, giving rise to different needs . Implementing just transition
    principles through collective and participatory decision-making processes is an
    effective way of integrating equity principles into policies at all scales depending
    on national circumstances, while in several countries just transition commissions,
    task forces and national policies have been established .  Many economic and regulatory
    instruments have been effective in reducing emissions and practical experience
    has informed instrument design to improve them while addressing distributional
    goals and social acceptance. The design of behavioural interventions, including
    the way that choices are presented to consumers work synergistically with price
    signals, making the combination more effective. Individuals with high socio-economic
    status contribute disproportionately to emissions, and have the highest potential
    for emissions reductions, e.g., as citizens, investors, consumers, role models,
    and professionals . There are options on design of instruments such as taxes,
    subsidies, prices, and consumption-based approaches, complemented by regulatory
    instruments to reduce high-emissions consumption while improving equity and societal
    well-being. Behaviour and lifestyle changes to help end-users adopt low-GHG-intensive
    options can be supported by policies, infrastructure and technology with multiple
    co-benefits for societal well-being. Broadening equitable access to domestic and
    international finance, technologies and capacity can also act as a catalyst for
    accelerating mitigation and shifting development pathways in low-income contexts
    . Eradicating extreme poverty, energy poverty, and providing decent living standards
    to all in these regions in the context of achieving sustainable development objectives,
    in the near term, can be achieved without significant global emissions growth.
    Technology development, transfer, capacity building and financing can support
    developing countries/ regions leapfrogging or transitioning to low-emissions transport
    systems thereby providing multiple co-benefits . Climate resilient development
    is advanced when actors work in equitable, just and enabling ways to reconcile
    divergent interests, values and worldviews, toward equitable and just outcomes
    .
  A.2.3:
  - Observed Climate System Changes and Impacts to  Date It is unequivocal that human
    influence has warmed the atmosphere, ocean and land. Widespread and rapid changes
    in the atmosphere, ocean, cryosphere and biosphere have occurred . The scale of
    recent changes across the climate system as a whole and the present state of many
    aspects of the climate system are unprecedented over many centuries to many thousands
    of years. It is very likely that GHG emissions were the main driver of tropospheric
    warming and extremely likely that human-caused stratospheric ozone depletion was
    the main driver of stratospheric cooling between 1979 and the mid-1990s. It is
    virtually certain that the global upper ocean has warmed since the 1970s and extremely
    likely that human influence is the main driver. Ocean warming accounted for 91%
    of the heating in the climate system, with land warming, ice loss and atmospheric
    warming accounting for about 5%, 3% and 1%, respectively. Global mean sea level
    increased by 0.20 [0.15 to 0.25] m between 1901 and 2018. The average rate of
    sea level rise was 1.3 [0.6 to 2.1]mm yr-1 between 1901 and 1971, increasing to
    1.9 [0.8 to 2.9] mm yr-1 between 1971 and 2006, and further increasing to 3.7
    [3.2 to –4.2] mm yr -1 between 2006 and 2018. Human influence was very likely
    the main driver of these increases since at least 1971. Human influence is very
    likely the main driver of the global retreat of glaciers since the 1990s and the
    decrease in Arctic sea ice area between 1979–1988 and 2010–2019. Human influence
    has also very likely contributed to decreased Northern Hemisphere spring snow
    cover and surface melting of the Greenland ice sheet. It is virtually certain
    that human-caused CO2 emissions are the main driver of current global acidification
    of the surface open ocean.  Human-caused climate change is already affecting many
    weather and climate extremes in every region across the globe. Evidence of observed
    changes in extremes such as heatwaves, heavy precipitation, droughts, and tropical
    cyclones, and, in particular, their attribution to human influence, has strengthened
    since AR5. It is virtually certain that hot extremes have become more frequent
    and more intense across most land regions since the 1950s, while cold extremes
    have become less frequent and less severe, with high confidence that human-caused
    climate change is the main driver of these changes. Marine heatwaves have approximately
    doubled in frequency since the 1980s, and human influence has very likely contributed
    to most of them since at least 2006. The frequency and intensity of heavy precipitation
    events have increased since the 1950s over most land areas for which observational
    data are sufficient for trend analysis, and human-caused climate change is likely
    the main driver. Human-caused climate change has contributed to increases in agricultural
    and ecological droughts in some regions due to increased land evapotranspiration
    . It is likely that the global proportion of major tropical cyclone occurrence
    has increased over the last four decades.  Climate change has caused substantial
    damages, and increasingly irreversible losses, in terrestrial, freshwater, cryospheric
    and coastal and open ocean ecosystems. The extent and magnitude of climate change
    impacts are larger than estimated in previous assessments. Approximately half
    of the species assessed globally have shifted polewards or, on land, also to higher
    elevations. Biological responses including changes in geographic placement and
    shifting seasonal timing are often not sufficient to cope with recent climate
    change. Hundreds of local losses of species have been driven by increases in the
    magnitude of heat extremes and mass mortality events on land and in the ocean.
    Impacts on some ecosystems are approaching irreversibility such as the impacts
    of hydrological changes resulting from the retreat of glaciers, or the changes
    in some mountain and Arctic ecosystems driven by permafrost thaw. Impacts in ecosystems
    from slow-onset processes such as ocean acidification, sea level rise or regional
    decreases in precipitation have also been attributed to human-caused climate change.
    Climate change has contributed to desertification and exacerbated land degradation,
    particularly in low lying coastal areas, river deltas, drylands and in permafrost
    areas. Nearly 50% of coastal wetlands have been lost over the last 100 years,
    as a result of the combined effects of localised human pressures, sea level rise,
    warming and extreme climate events.  Climate change has reduced food security
    and affected water security due to warming, changing precipitation patterns, reduction
    and loss of cryospheric elements, and greater frequency and intensity of climatic
    extremes, thereby hindering efforts to meet Sustainable Development Goals. Although
    overall agricultural productivity has increased, climate change has slowed this
    growth in agricultural productivity over the past 50 years globally , with related
    negative crop yield impacts mainly recorded in mid- and low latitude regions,
    and some positive impacts in some high latitude regions. Ocean warming in the
    20th century and beyond has contributed to an overall decrease in maximum catch
    potential, compounding the impacts from overfishing for some fish stocks. Ocean
    warming and ocean acidification have adversely affected food production from shellfish
    aquaculture and fisheries in some oceanic regions . Current levels of global warming
    are associated with moderate risks from increased dryland water scarcity. Roughly
    half of the world’s population currently experiences severe water scarcity for
    at least some part of the year due to a combination of climatic and non-climatic
    drivers. Unsustainable agricultural expansion, driven in part by unbalanced diets
    , increases ecosystem and human vulnerability and leads to competition for land
    and/or water resources. Increasing weather and climate extreme events have exposed
    millions of people to acute food insecurity and reduced water security, with the
    largest impacts observed in many locations and/or communities in Africa, Asia,
    Central and South America, LDCs, Small Islands and the Arctic, and for small-scale
    food producers, low-income households and Indigenous Peoples globally.  In urban
    settings, climate change has caused adverse impacts on human health, livelihoods
    and key infrastructure. Hot extremes including heatwaves have intensified in cities
    , where they have also worsened air pollution events and limited functioning of
    key infrastructure . Urban infrastructure, including transportation, water, sanitation
    and energy systems have been compromised by extreme and slow-onset events , with
    resulting economic losses, disruptions of services and impacts to well-being.
    Observed impacts are concentrated amongst economically and socially marginalised
    urban residents, e.g., those living in informal settlements. Cities intensify
    human-caused warming locally, while urbanisation also increases mean and heavy
    precipitation over and/or downwind of cities and resulting runoff intensity .  Climate
    change has adversely affected human physical health globally and mental health
    in assessed regions, and is contributing to humanitarian crises where climate
    hazards interact with high vulnerability. In all regions increases in extreme
    heat events have resulted in human mortality and morbidity . The occurrence of
    climate-related food-borne and water-borne diseases has increased. The incidence
    of vector-borne diseases has increased from range expansion and/or increased reproduction
    of disease vectors. Animal and human diseases, including zoonoses, are emerging
    in new areas . In assessed regions, some mental health challenges are associated
    with increasing temperatures, trauma from extreme events, and loss of livelihoods
    and culture . Climate change impacts on health are mediated through natural and
    human systems, including economic and social conditions and disruptions. Climate
    and weather extremes are increasingly driving displacement in Africa, Asia, North
    America, and Central and South America , with small island states in the Caribbean
    and South Pacific being disproportionately affected relative to their small population
    size. Through displacement and involuntary migration from extreme weather and
    climate events, climate change has generated and perpetuated vulnerability .  Human
    influence has likely increased the chance of compound extreme events since the
    1950s. Concurrent and repeated climate hazards have occurred in all regions, increasing
    impacts and risks to health, ecosystems, infrastructure, livelihoods and food
    . Compound extreme events include increases in the frequency of concurrent heatwaves
    and droughts; fire weather in some regions; and compound flooding in some locations.
    Multiple risks interact, generating new sources of vulnerability to climate hazards,
    and compounding overall risk. Compound climate hazards can overwhelm adaptive
    capacity and substantially increase damage ).  Economic impacts attributable to
    climate change are increasingly affecting peoples’ livelihoods and are causing
    economic and societal impacts across national boundaries. Economic damages from
    climate change have been detected in climate-exposed sectors, with regional effects
    to agriculture, forestry, fishery, energy, and tourism, and through outdoor labour
    productivity with some exceptions of positive impacts in regions with low energy
    demand and comparative advantages in agricultural markets and tourism. Individual
    livelihoods have been affected through changes in agricultural productivity, impacts
    on human health and food security, destruction of homes and infrastructure, and
    loss of property and income, with adverse effects on gender and social equity
    . Tropical cyclones have reduced economic growth in the short-term. Event attribution
    studies and physical understanding indicate that human-caused climate change increases
    heavy precipitation associated with tropical cyclones. Wildfires in many regions
    have affected built assets, economic activity, and health. In cities and settlements,
    climate impacts to key infrastructure are leading to losses and damages across
    water and food systems, and affect economic activity, with impacts extending beyond
    the area directly impacted by the climate hazard.  Climate change has caused widespread
    adverse impacts and related losses and damages to nature and people . Losses and
    damages are unequally distributed across systems, regions and sectors. Cultural
    losses, related to tangible and intangible heritage, threaten adaptive capacity
    and may result in irrevocable losses of sense of belonging, valued cultural practices,
    identity and home, particularly for Indigenous Peoples and those more directly
    reliant on the environment for subsistence. For example, changes in snow cover,
    lake and river ice, and permafrost in many Arctic regions, are harming the livelihoods
    and cultural identity of Arctic residents including Indigenous populations. Infrastructure,
    including transportation, water, sanitation and energy systems have been compromised
    by extreme and slow-onset events, with resulting economic losses, disruptions
    of services and impacts to well-being.  Across sectors and regions, the most vulnerable
    people and systems have been disproportionately affected by the impacts of climate
    change. LDCs and SIDS who have much lower per capita emissions than the global
    average excluding CO2-LULUCF, also have high vulnerability to climatic hazards,
    with global hotspots of high human vulnerability observed in West-, Central- and
    East Africa, South Asia, Central and South America, SIDS and the Arctic. Regions
    and people with considerable development constraints have high vulnerability to
    climatic hazards. Vulnerability is higher in locations with poverty, governance
    challenges and limited access to basic services and resources, violent conflict
    and high levels of climate-sensitive livelihoods  . Vulnerability at different
    spatial levels is exacerbated by inequity and marginalisation linked to gender,
    ethnicity, low income or combinations thereof, especially for many Indigenous
    Peoples and local communities. Approximately 3.3 to 3.6 billion people live in
    contexts that are highly vulnerable to climate change. Between 2010 and 2020,
    human mortality from floods, droughts and storms was 15 times higher in highly
    vulnerable regions, compared to regions with very low vulnerability. In the Arctic
    and in some high mountain regions, negative impacts of cryosphere change have
    been especially felt among Indigenous Peoples. Human and ecosystem vulnerability
    are interdependent. Vulnerability of ecosystems and people to climate change differs
    substantially among and within regions, driven by patterns of intersecting socio-economic
    development, unsustainable ocean and land use, inequity, marginalisation, historical
    and ongoing patterns of inequity such as colonialism, and governance.
  A.2.4:
  - Observed Climate System Changes and Impacts to  Date It is unequivocal that human
    influence has warmed the atmosphere, ocean and land. Widespread and rapid changes
    in the atmosphere, ocean, cryosphere and biosphere have occurred . The scale of
    recent changes across the climate system as a whole and the present state of many
    aspects of the climate system are unprecedented over many centuries to many thousands
    of years. It is very likely that GHG emissions were the main driver of tropospheric
    warming and extremely likely that human-caused stratospheric ozone depletion was
    the main driver of stratospheric cooling between 1979 and the mid-1990s. It is
    virtually certain that the global upper ocean has warmed since the 1970s and extremely
    likely that human influence is the main driver. Ocean warming accounted for 91%
    of the heating in the climate system, with land warming, ice loss and atmospheric
    warming accounting for about 5%, 3% and 1%, respectively. Global mean sea level
    increased by 0.20 [0.15 to 0.25] m between 1901 and 2018. The average rate of
    sea level rise was 1.3 [0.6 to 2.1]mm yr-1 between 1901 and 1971, increasing to
    1.9 [0.8 to 2.9] mm yr-1 between 1971 and 2006, and further increasing to 3.7
    [3.2 to –4.2] mm yr -1 between 2006 and 2018. Human influence was very likely
    the main driver of these increases since at least 1971. Human influence is very
    likely the main driver of the global retreat of glaciers since the 1990s and the
    decrease in Arctic sea ice area between 1979–1988 and 2010–2019. Human influence
    has also very likely contributed to decreased Northern Hemisphere spring snow
    cover and surface melting of the Greenland ice sheet. It is virtually certain
    that human-caused CO2 emissions are the main driver of current global acidification
    of the surface open ocean.  Human-caused climate change is already affecting many
    weather and climate extremes in every region across the globe. Evidence of observed
    changes in extremes such as heatwaves, heavy precipitation, droughts, and tropical
    cyclones, and, in particular, their attribution to human influence, has strengthened
    since AR5. It is virtually certain that hot extremes have become more frequent
    and more intense across most land regions since the 1950s, while cold extremes
    have become less frequent and less severe, with high confidence that human-caused
    climate change is the main driver of these changes. Marine heatwaves have approximately
    doubled in frequency since the 1980s, and human influence has very likely contributed
    to most of them since at least 2006. The frequency and intensity of heavy precipitation
    events have increased since the 1950s over most land areas for which observational
    data are sufficient for trend analysis, and human-caused climate change is likely
    the main driver. Human-caused climate change has contributed to increases in agricultural
    and ecological droughts in some regions due to increased land evapotranspiration
    . It is likely that the global proportion of major tropical cyclone occurrence
    has increased over the last four decades.  Climate change has caused substantial
    damages, and increasingly irreversible losses, in terrestrial, freshwater, cryospheric
    and coastal and open ocean ecosystems. The extent and magnitude of climate change
    impacts are larger than estimated in previous assessments. Approximately half
    of the species assessed globally have shifted polewards or, on land, also to higher
    elevations. Biological responses including changes in geographic placement and
    shifting seasonal timing are often not sufficient to cope with recent climate
    change. Hundreds of local losses of species have been driven by increases in the
    magnitude of heat extremes and mass mortality events on land and in the ocean.
    Impacts on some ecosystems are approaching irreversibility such as the impacts
    of hydrological changes resulting from the retreat of glaciers, or the changes
    in some mountain and Arctic ecosystems driven by permafrost thaw. Impacts in ecosystems
    from slow-onset processes such as ocean acidification, sea level rise or regional
    decreases in precipitation have also been attributed to human-caused climate change.
    Climate change has contributed to desertification and exacerbated land degradation,
    particularly in low lying coastal areas, river deltas, drylands and in permafrost
    areas. Nearly 50% of coastal wetlands have been lost over the last 100 years,
    as a result of the combined effects of localised human pressures, sea level rise,
    warming and extreme climate events.  Climate change has reduced food security
    and affected water security due to warming, changing precipitation patterns, reduction
    and loss of cryospheric elements, and greater frequency and intensity of climatic
    extremes, thereby hindering efforts to meet Sustainable Development Goals. Although
    overall agricultural productivity has increased, climate change has slowed this
    growth in agricultural productivity over the past 50 years globally , with related
    negative crop yield impacts mainly recorded in mid- and low latitude regions,
    and some positive impacts in some high latitude regions. Ocean warming in the
    20th century and beyond has contributed to an overall decrease in maximum catch
    potential, compounding the impacts from overfishing for some fish stocks. Ocean
    warming and ocean acidification have adversely affected food production from shellfish
    aquaculture and fisheries in some oceanic regions . Current levels of global warming
    are associated with moderate risks from increased dryland water scarcity. Roughly
    half of the world’s population currently experiences severe water scarcity for
    at least some part of the year due to a combination of climatic and non-climatic
    drivers. Unsustainable agricultural expansion, driven in part by unbalanced diets
    , increases ecosystem and human vulnerability and leads to competition for land
    and/or water resources. Increasing weather and climate extreme events have exposed
    millions of people to acute food insecurity and reduced water security, with the
    largest impacts observed in many locations and/or communities in Africa, Asia,
    Central and South America, LDCs, Small Islands and the Arctic, and for small-scale
    food producers, low-income households and Indigenous Peoples globally.  In urban
    settings, climate change has caused adverse impacts on human health, livelihoods
    and key infrastructure. Hot extremes including heatwaves have intensified in cities
    , where they have also worsened air pollution events and limited functioning of
    key infrastructure . Urban infrastructure, including transportation, water, sanitation
    and energy systems have been compromised by extreme and slow-onset events , with
    resulting economic losses, disruptions of services and impacts to well-being.
    Observed impacts are concentrated amongst economically and socially marginalised
    urban residents, e.g., those living in informal settlements. Cities intensify
    human-caused warming locally, while urbanisation also increases mean and heavy
    precipitation over and/or downwind of cities and resulting runoff intensity .  Climate
    change has adversely affected human physical health globally and mental health
    in assessed regions, and is contributing to humanitarian crises where climate
    hazards interact with high vulnerability. In all regions increases in extreme
    heat events have resulted in human mortality and morbidity . The occurrence of
    climate-related food-borne and water-borne diseases has increased. The incidence
    of vector-borne diseases has increased from range expansion and/or increased reproduction
    of disease vectors. Animal and human diseases, including zoonoses, are emerging
    in new areas . In assessed regions, some mental health challenges are associated
    with increasing temperatures, trauma from extreme events, and loss of livelihoods
    and culture . Climate change impacts on health are mediated through natural and
    human systems, including economic and social conditions and disruptions. Climate
    and weather extremes are increasingly driving displacement in Africa, Asia, North
    America, and Central and South America , with small island states in the Caribbean
    and South Pacific being disproportionately affected relative to their small population
    size. Through displacement and involuntary migration from extreme weather and
    climate events, climate change has generated and perpetuated vulnerability .  Human
    influence has likely increased the chance of compound extreme events since the
    1950s. Concurrent and repeated climate hazards have occurred in all regions, increasing
    impacts and risks to health, ecosystems, infrastructure, livelihoods and food
    . Compound extreme events include increases in the frequency of concurrent heatwaves
    and droughts; fire weather in some regions; and compound flooding in some locations.
    Multiple risks interact, generating new sources of vulnerability to climate hazards,
    and compounding overall risk. Compound climate hazards can overwhelm adaptive
    capacity and substantially increase damage ).  Economic impacts attributable to
    climate change are increasingly affecting peoples’ livelihoods and are causing
    economic and societal impacts across national boundaries. Economic damages from
    climate change have been detected in climate-exposed sectors, with regional effects
    to agriculture, forestry, fishery, energy, and tourism, and through outdoor labour
    productivity with some exceptions of positive impacts in regions with low energy
    demand and comparative advantages in agricultural markets and tourism. Individual
    livelihoods have been affected through changes in agricultural productivity, impacts
    on human health and food security, destruction of homes and infrastructure, and
    loss of property and income, with adverse effects on gender and social equity
    . Tropical cyclones have reduced economic growth in the short-term. Event attribution
    studies and physical understanding indicate that human-caused climate change increases
    heavy precipitation associated with tropical cyclones. Wildfires in many regions
    have affected built assets, economic activity, and health. In cities and settlements,
    climate impacts to key infrastructure are leading to losses and damages across
    water and food systems, and affect economic activity, with impacts extending beyond
    the area directly impacted by the climate hazard.  Climate change has caused widespread
    adverse impacts and related losses and damages to nature and people . Losses and
    damages are unequally distributed across systems, regions and sectors. Cultural
    losses, related to tangible and intangible heritage, threaten adaptive capacity
    and may result in irrevocable losses of sense of belonging, valued cultural practices,
    identity and home, particularly for Indigenous Peoples and those more directly
    reliant on the environment for subsistence. For example, changes in snow cover,
    lake and river ice, and permafrost in many Arctic regions, are harming the livelihoods
    and cultural identity of Arctic residents including Indigenous populations. Infrastructure,
    including transportation, water, sanitation and energy systems have been compromised
    by extreme and slow-onset events, with resulting economic losses, disruptions
    of services and impacts to well-being.  Across sectors and regions, the most vulnerable
    people and systems have been disproportionately affected by the impacts of climate
    change. LDCs and SIDS who have much lower per capita emissions than the global
    average excluding CO2-LULUCF, also have high vulnerability to climatic hazards,
    with global hotspots of high human vulnerability observed in West-, Central- and
    East Africa, South Asia, Central and South America, SIDS and the Arctic. Regions
    and people with considerable development constraints have high vulnerability to
    climatic hazards. Vulnerability is higher in locations with poverty, governance
    challenges and limited access to basic services and resources, violent conflict
    and high levels of climate-sensitive livelihoods  . Vulnerability at different
    spatial levels is exacerbated by inequity and marginalisation linked to gender,
    ethnicity, low income or combinations thereof, especially for many Indigenous
    Peoples and local communities. Approximately 3.3 to 3.6 billion people live in
    contexts that are highly vulnerable to climate change. Between 2010 and 2020,
    human mortality from floods, droughts and storms was 15 times higher in highly
    vulnerable regions, compared to regions with very low vulnerability. In the Arctic
    and in some high mountain regions, negative impacts of cryosphere change have
    been especially felt among Indigenous Peoples. Human and ecosystem vulnerability
    are interdependent. Vulnerability of ecosystems and people to climate change differs
    substantially among and within regions, driven by patterns of intersecting socio-economic
    development, unsustainable ocean and land use, inequity, marginalisation, historical
    and ongoing patterns of inequity such as colonialism, and governance.
  A.2.5:
  - Observed Climate System Changes and Impacts to  Date It is unequivocal that human
    influence has warmed the atmosphere, ocean and land. Widespread and rapid changes
    in the atmosphere, ocean, cryosphere and biosphere have occurred . The scale of
    recent changes across the climate system as a whole and the present state of many
    aspects of the climate system are unprecedented over many centuries to many thousands
    of years. It is very likely that GHG emissions were the main driver of tropospheric
    warming and extremely likely that human-caused stratospheric ozone depletion was
    the main driver of stratospheric cooling between 1979 and the mid-1990s. It is
    virtually certain that the global upper ocean has warmed since the 1970s and extremely
    likely that human influence is the main driver. Ocean warming accounted for 91%
    of the heating in the climate system, with land warming, ice loss and atmospheric
    warming accounting for about 5%, 3% and 1%, respectively. Global mean sea level
    increased by 0.20 [0.15 to 0.25] m between 1901 and 2018. The average rate of
    sea level rise was 1.3 [0.6 to 2.1]mm yr-1 between 1901 and 1971, increasing to
    1.9 [0.8 to 2.9] mm yr-1 between 1971 and 2006, and further increasing to 3.7
    [3.2 to –4.2] mm yr -1 between 2006 and 2018. Human influence was very likely
    the main driver of these increases since at least 1971. Human influence is very
    likely the main driver of the global retreat of glaciers since the 1990s and the
    decrease in Arctic sea ice area between 1979–1988 and 2010–2019. Human influence
    has also very likely contributed to decreased Northern Hemisphere spring snow
    cover and surface melting of the Greenland ice sheet. It is virtually certain
    that human-caused CO2 emissions are the main driver of current global acidification
    of the surface open ocean.  Human-caused climate change is already affecting many
    weather and climate extremes in every region across the globe. Evidence of observed
    changes in extremes such as heatwaves, heavy precipitation, droughts, and tropical
    cyclones, and, in particular, their attribution to human influence, has strengthened
    since AR5. It is virtually certain that hot extremes have become more frequent
    and more intense across most land regions since the 1950s, while cold extremes
    have become less frequent and less severe, with high confidence that human-caused
    climate change is the main driver of these changes. Marine heatwaves have approximately
    doubled in frequency since the 1980s, and human influence has very likely contributed
    to most of them since at least 2006. The frequency and intensity of heavy precipitation
    events have increased since the 1950s over most land areas for which observational
    data are sufficient for trend analysis, and human-caused climate change is likely
    the main driver. Human-caused climate change has contributed to increases in agricultural
    and ecological droughts in some regions due to increased land evapotranspiration
    . It is likely that the global proportion of major tropical cyclone occurrence
    has increased over the last four decades.  Climate change has caused substantial
    damages, and increasingly irreversible losses, in terrestrial, freshwater, cryospheric
    and coastal and open ocean ecosystems. The extent and magnitude of climate change
    impacts are larger than estimated in previous assessments. Approximately half
    of the species assessed globally have shifted polewards or, on land, also to higher
    elevations. Biological responses including changes in geographic placement and
    shifting seasonal timing are often not sufficient to cope with recent climate
    change. Hundreds of local losses of species have been driven by increases in the
    magnitude of heat extremes and mass mortality events on land and in the ocean.
    Impacts on some ecosystems are approaching irreversibility such as the impacts
    of hydrological changes resulting from the retreat of glaciers, or the changes
    in some mountain and Arctic ecosystems driven by permafrost thaw. Impacts in ecosystems
    from slow-onset processes such as ocean acidification, sea level rise or regional
    decreases in precipitation have also been attributed to human-caused climate change.
    Climate change has contributed to desertification and exacerbated land degradation,
    particularly in low lying coastal areas, river deltas, drylands and in permafrost
    areas. Nearly 50% of coastal wetlands have been lost over the last 100 years,
    as a result of the combined effects of localised human pressures, sea level rise,
    warming and extreme climate events.  Climate change has reduced food security
    and affected water security due to warming, changing precipitation patterns, reduction
    and loss of cryospheric elements, and greater frequency and intensity of climatic
    extremes, thereby hindering efforts to meet Sustainable Development Goals. Although
    overall agricultural productivity has increased, climate change has slowed this
    growth in agricultural productivity over the past 50 years globally , with related
    negative crop yield impacts mainly recorded in mid- and low latitude regions,
    and some positive impacts in some high latitude regions. Ocean warming in the
    20th century and beyond has contributed to an overall decrease in maximum catch
    potential, compounding the impacts from overfishing for some fish stocks. Ocean
    warming and ocean acidification have adversely affected food production from shellfish
    aquaculture and fisheries in some oceanic regions . Current levels of global warming
    are associated with moderate risks from increased dryland water scarcity. Roughly
    half of the world’s population currently experiences severe water scarcity for
    at least some part of the year due to a combination of climatic and non-climatic
    drivers. Unsustainable agricultural expansion, driven in part by unbalanced diets
    , increases ecosystem and human vulnerability and leads to competition for land
    and/or water resources. Increasing weather and climate extreme events have exposed
    millions of people to acute food insecurity and reduced water security, with the
    largest impacts observed in many locations and/or communities in Africa, Asia,
    Central and South America, LDCs, Small Islands and the Arctic, and for small-scale
    food producers, low-income households and Indigenous Peoples globally.  In urban
    settings, climate change has caused adverse impacts on human health, livelihoods
    and key infrastructure. Hot extremes including heatwaves have intensified in cities
    , where they have also worsened air pollution events and limited functioning of
    key infrastructure . Urban infrastructure, including transportation, water, sanitation
    and energy systems have been compromised by extreme and slow-onset events , with
    resulting economic losses, disruptions of services and impacts to well-being.
    Observed impacts are concentrated amongst economically and socially marginalised
    urban residents, e.g., those living in informal settlements. Cities intensify
    human-caused warming locally, while urbanisation also increases mean and heavy
    precipitation over and/or downwind of cities and resulting runoff intensity .  Climate
    change has adversely affected human physical health globally and mental health
    in assessed regions, and is contributing to humanitarian crises where climate
    hazards interact with high vulnerability. In all regions increases in extreme
    heat events have resulted in human mortality and morbidity . The occurrence of
    climate-related food-borne and water-borne diseases has increased. The incidence
    of vector-borne diseases has increased from range expansion and/or increased reproduction
    of disease vectors. Animal and human diseases, including zoonoses, are emerging
    in new areas . In assessed regions, some mental health challenges are associated
    with increasing temperatures, trauma from extreme events, and loss of livelihoods
    and culture . Climate change impacts on health are mediated through natural and
    human systems, including economic and social conditions and disruptions. Climate
    and weather extremes are increasingly driving displacement in Africa, Asia, North
    America, and Central and South America , with small island states in the Caribbean
    and South Pacific being disproportionately affected relative to their small population
    size. Through displacement and involuntary migration from extreme weather and
    climate events, climate change has generated and perpetuated vulnerability .  Human
    influence has likely increased the chance of compound extreme events since the
    1950s. Concurrent and repeated climate hazards have occurred in all regions, increasing
    impacts and risks to health, ecosystems, infrastructure, livelihoods and food
    . Compound extreme events include increases in the frequency of concurrent heatwaves
    and droughts; fire weather in some regions; and compound flooding in some locations.
    Multiple risks interact, generating new sources of vulnerability to climate hazards,
    and compounding overall risk. Compound climate hazards can overwhelm adaptive
    capacity and substantially increase damage ).  Economic impacts attributable to
    climate change are increasingly affecting peoples’ livelihoods and are causing
    economic and societal impacts across national boundaries. Economic damages from
    climate change have been detected in climate-exposed sectors, with regional effects
    to agriculture, forestry, fishery, energy, and tourism, and through outdoor labour
    productivity with some exceptions of positive impacts in regions with low energy
    demand and comparative advantages in agricultural markets and tourism. Individual
    livelihoods have been affected through changes in agricultural productivity, impacts
    on human health and food security, destruction of homes and infrastructure, and
    loss of property and income, with adverse effects on gender and social equity
    . Tropical cyclones have reduced economic growth in the short-term. Event attribution
    studies and physical understanding indicate that human-caused climate change increases
    heavy precipitation associated with tropical cyclones. Wildfires in many regions
    have affected built assets, economic activity, and health. In cities and settlements,
    climate impacts to key infrastructure are leading to losses and damages across
    water and food systems, and affect economic activity, with impacts extending beyond
    the area directly impacted by the climate hazard.  Climate change has caused widespread
    adverse impacts and related losses and damages to nature and people . Losses and
    damages are unequally distributed across systems, regions and sectors. Cultural
    losses, related to tangible and intangible heritage, threaten adaptive capacity
    and may result in irrevocable losses of sense of belonging, valued cultural practices,
    identity and home, particularly for Indigenous Peoples and those more directly
    reliant on the environment for subsistence. For example, changes in snow cover,
    lake and river ice, and permafrost in many Arctic regions, are harming the livelihoods
    and cultural identity of Arctic residents including Indigenous populations. Infrastructure,
    including transportation, water, sanitation and energy systems have been compromised
    by extreme and slow-onset events, with resulting economic losses, disruptions
    of services and impacts to well-being.  Across sectors and regions, the most vulnerable
    people and systems have been disproportionately affected by the impacts of climate
    change. LDCs and SIDS who have much lower per capita emissions than the global
    average excluding CO2-LULUCF, also have high vulnerability to climatic hazards,
    with global hotspots of high human vulnerability observed in West-, Central- and
    East Africa, South Asia, Central and South America, SIDS and the Arctic. Regions
    and people with considerable development constraints have high vulnerability to
    climatic hazards. Vulnerability is higher in locations with poverty, governance
    challenges and limited access to basic services and resources, violent conflict
    and high levels of climate-sensitive livelihoods  . Vulnerability at different
    spatial levels is exacerbated by inequity and marginalisation linked to gender,
    ethnicity, low income or combinations thereof, especially for many Indigenous
    Peoples and local communities. Approximately 3.3 to 3.6 billion people live in
    contexts that are highly vulnerable to climate change. Between 2010 and 2020,
    human mortality from floods, droughts and storms was 15 times higher in highly
    vulnerable regions, compared to regions with very low vulnerability. In the Arctic
    and in some high mountain regions, negative impacts of cryosphere change have
    been especially felt among Indigenous Peoples. Human and ecosystem vulnerability
    are interdependent. Vulnerability of ecosystems and people to climate change differs
    substantially among and within regions, driven by patterns of intersecting socio-economic
    development, unsustainable ocean and land use, inequity, marginalisation, historical
    and ongoing patterns of inequity such as colonialism, and governance.
  A.2.6:
  - Observed Climate System Changes and Impacts to  Date It is unequivocal that human
    influence has warmed the atmosphere, ocean and land. Widespread and rapid changes
    in the atmosphere, ocean, cryosphere and biosphere have occurred . The scale of
    recent changes across the climate system as a whole and the present state of many
    aspects of the climate system are unprecedented over many centuries to many thousands
    of years. It is very likely that GHG emissions were the main driver of tropospheric
    warming and extremely likely that human-caused stratospheric ozone depletion was
    the main driver of stratospheric cooling between 1979 and the mid-1990s. It is
    virtually certain that the global upper ocean has warmed since the 1970s and extremely
    likely that human influence is the main driver. Ocean warming accounted for 91%
    of the heating in the climate system, with land warming, ice loss and atmospheric
    warming accounting for about 5%, 3% and 1%, respectively. Global mean sea level
    increased by 0.20 [0.15 to 0.25] m between 1901 and 2018. The average rate of
    sea level rise was 1.3 [0.6 to 2.1]mm yr-1 between 1901 and 1971, increasing to
    1.9 [0.8 to 2.9] mm yr-1 between 1971 and 2006, and further increasing to 3.7
    [3.2 to –4.2] mm yr -1 between 2006 and 2018. Human influence was very likely
    the main driver of these increases since at least 1971. Human influence is very
    likely the main driver of the global retreat of glaciers since the 1990s and the
    decrease in Arctic sea ice area between 1979–1988 and 2010–2019. Human influence
    has also very likely contributed to decreased Northern Hemisphere spring snow
    cover and surface melting of the Greenland ice sheet. It is virtually certain
    that human-caused CO2 emissions are the main driver of current global acidification
    of the surface open ocean.  Human-caused climate change is already affecting many
    weather and climate extremes in every region across the globe. Evidence of observed
    changes in extremes such as heatwaves, heavy precipitation, droughts, and tropical
    cyclones, and, in particular, their attribution to human influence, has strengthened
    since AR5. It is virtually certain that hot extremes have become more frequent
    and more intense across most land regions since the 1950s, while cold extremes
    have become less frequent and less severe, with high confidence that human-caused
    climate change is the main driver of these changes. Marine heatwaves have approximately
    doubled in frequency since the 1980s, and human influence has very likely contributed
    to most of them since at least 2006. The frequency and intensity of heavy precipitation
    events have increased since the 1950s over most land areas for which observational
    data are sufficient for trend analysis, and human-caused climate change is likely
    the main driver. Human-caused climate change has contributed to increases in agricultural
    and ecological droughts in some regions due to increased land evapotranspiration
    . It is likely that the global proportion of major tropical cyclone occurrence
    has increased over the last four decades.  Climate change has caused substantial
    damages, and increasingly irreversible losses, in terrestrial, freshwater, cryospheric
    and coastal and open ocean ecosystems. The extent and magnitude of climate change
    impacts are larger than estimated in previous assessments. Approximately half
    of the species assessed globally have shifted polewards or, on land, also to higher
    elevations. Biological responses including changes in geographic placement and
    shifting seasonal timing are often not sufficient to cope with recent climate
    change. Hundreds of local losses of species have been driven by increases in the
    magnitude of heat extremes and mass mortality events on land and in the ocean.
    Impacts on some ecosystems are approaching irreversibility such as the impacts
    of hydrological changes resulting from the retreat of glaciers, or the changes
    in some mountain and Arctic ecosystems driven by permafrost thaw. Impacts in ecosystems
    from slow-onset processes such as ocean acidification, sea level rise or regional
    decreases in precipitation have also been attributed to human-caused climate change.
    Climate change has contributed to desertification and exacerbated land degradation,
    particularly in low lying coastal areas, river deltas, drylands and in permafrost
    areas. Nearly 50% of coastal wetlands have been lost over the last 100 years,
    as a result of the combined effects of localised human pressures, sea level rise,
    warming and extreme climate events.  Climate change has reduced food security
    and affected water security due to warming, changing precipitation patterns, reduction
    and loss of cryospheric elements, and greater frequency and intensity of climatic
    extremes, thereby hindering efforts to meet Sustainable Development Goals. Although
    overall agricultural productivity has increased, climate change has slowed this
    growth in agricultural productivity over the past 50 years globally , with related
    negative crop yield impacts mainly recorded in mid- and low latitude regions,
    and some positive impacts in some high latitude regions. Ocean warming in the
    20th century and beyond has contributed to an overall decrease in maximum catch
    potential, compounding the impacts from overfishing for some fish stocks. Ocean
    warming and ocean acidification have adversely affected food production from shellfish
    aquaculture and fisheries in some oceanic regions . Current levels of global warming
    are associated with moderate risks from increased dryland water scarcity. Roughly
    half of the world’s population currently experiences severe water scarcity for
    at least some part of the year due to a combination of climatic and non-climatic
    drivers. Unsustainable agricultural expansion, driven in part by unbalanced diets
    , increases ecosystem and human vulnerability and leads to competition for land
    and/or water resources. Increasing weather and climate extreme events have exposed
    millions of people to acute food insecurity and reduced water security, with the
    largest impacts observed in many locations and/or communities in Africa, Asia,
    Central and South America, LDCs, Small Islands and the Arctic, and for small-scale
    food producers, low-income households and Indigenous Peoples globally.  In urban
    settings, climate change has caused adverse impacts on human health, livelihoods
    and key infrastructure. Hot extremes including heatwaves have intensified in cities
    , where they have also worsened air pollution events and limited functioning of
    key infrastructure . Urban infrastructure, including transportation, water, sanitation
    and energy systems have been compromised by extreme and slow-onset events , with
    resulting economic losses, disruptions of services and impacts to well-being.
    Observed impacts are concentrated amongst economically and socially marginalised
    urban residents, e.g., those living in informal settlements. Cities intensify
    human-caused warming locally, while urbanisation also increases mean and heavy
    precipitation over and/or downwind of cities and resulting runoff intensity .  Climate
    change has adversely affected human physical health globally and mental health
    in assessed regions, and is contributing to humanitarian crises where climate
    hazards interact with high vulnerability. In all regions increases in extreme
    heat events have resulted in human mortality and morbidity . The occurrence of
    climate-related food-borne and water-borne diseases has increased. The incidence
    of vector-borne diseases has increased from range expansion and/or increased reproduction
    of disease vectors. Animal and human diseases, including zoonoses, are emerging
    in new areas . In assessed regions, some mental health challenges are associated
    with increasing temperatures, trauma from extreme events, and loss of livelihoods
    and culture . Climate change impacts on health are mediated through natural and
    human systems, including economic and social conditions and disruptions. Climate
    and weather extremes are increasingly driving displacement in Africa, Asia, North
    America, and Central and South America , with small island states in the Caribbean
    and South Pacific being disproportionately affected relative to their small population
    size. Through displacement and involuntary migration from extreme weather and
    climate events, climate change has generated and perpetuated vulnerability .  Human
    influence has likely increased the chance of compound extreme events since the
    1950s. Concurrent and repeated climate hazards have occurred in all regions, increasing
    impacts and risks to health, ecosystems, infrastructure, livelihoods and food
    . Compound extreme events include increases in the frequency of concurrent heatwaves
    and droughts; fire weather in some regions; and compound flooding in some locations.
    Multiple risks interact, generating new sources of vulnerability to climate hazards,
    and compounding overall risk. Compound climate hazards can overwhelm adaptive
    capacity and substantially increase damage ).  Economic impacts attributable to
    climate change are increasingly affecting peoples’ livelihoods and are causing
    economic and societal impacts across national boundaries. Economic damages from
    climate change have been detected in climate-exposed sectors, with regional effects
    to agriculture, forestry, fishery, energy, and tourism, and through outdoor labour
    productivity with some exceptions of positive impacts in regions with low energy
    demand and comparative advantages in agricultural markets and tourism. Individual
    livelihoods have been affected through changes in agricultural productivity, impacts
    on human health and food security, destruction of homes and infrastructure, and
    loss of property and income, with adverse effects on gender and social equity
    . Tropical cyclones have reduced economic growth in the short-term. Event attribution
    studies and physical understanding indicate that human-caused climate change increases
    heavy precipitation associated with tropical cyclones. Wildfires in many regions
    have affected built assets, economic activity, and health. In cities and settlements,
    climate impacts to key infrastructure are leading to losses and damages across
    water and food systems, and affect economic activity, with impacts extending beyond
    the area directly impacted by the climate hazard.  Climate change has caused widespread
    adverse impacts and related losses and damages to nature and people . Losses and
    damages are unequally distributed across systems, regions and sectors. Cultural
    losses, related to tangible and intangible heritage, threaten adaptive capacity
    and may result in irrevocable losses of sense of belonging, valued cultural practices,
    identity and home, particularly for Indigenous Peoples and those more directly
    reliant on the environment for subsistence. For example, changes in snow cover,
    lake and river ice, and permafrost in many Arctic regions, are harming the livelihoods
    and cultural identity of Arctic residents including Indigenous populations. Infrastructure,
    including transportation, water, sanitation and energy systems have been compromised
    by extreme and slow-onset events, with resulting economic losses, disruptions
    of services and impacts to well-being.  Across sectors and regions, the most vulnerable
    people and systems have been disproportionately affected by the impacts of climate
    change. LDCs and SIDS who have much lower per capita emissions than the global
    average excluding CO2-LULUCF, also have high vulnerability to climatic hazards,
    with global hotspots of high human vulnerability observed in West-, Central- and
    East Africa, South Asia, Central and South America, SIDS and the Arctic. Regions
    and people with considerable development constraints have high vulnerability to
    climatic hazards. Vulnerability is higher in locations with poverty, governance
    challenges and limited access to basic services and resources, violent conflict
    and high levels of climate-sensitive livelihoods  . Vulnerability at different
    spatial levels is exacerbated by inequity and marginalisation linked to gender,
    ethnicity, low income or combinations thereof, especially for many Indigenous
    Peoples and local communities. Approximately 3.3 to 3.6 billion people live in
    contexts that are highly vulnerable to climate change. Between 2010 and 2020,
    human mortality from floods, droughts and storms was 15 times higher in highly
    vulnerable regions, compared to regions with very low vulnerability. In the Arctic
    and in some high mountain regions, negative impacts of cryosphere change have
    been especially felt among Indigenous Peoples. Human and ecosystem vulnerability
    are interdependent. Vulnerability of ecosystems and people to climate change differs
    substantially among and within regions, driven by patterns of intersecting socio-economic
    development, unsustainable ocean and land use, inequity, marginalisation, historical
    and ongoing patterns of inequity such as colonialism, and governance.
  A.2.7:
  - Observed Climate System Changes and Impacts to  Date It is unequivocal that human
    influence has warmed the atmosphere, ocean and land. Widespread and rapid changes
    in the atmosphere, ocean, cryosphere and biosphere have occurred . The scale of
    recent changes across the climate system as a whole and the present state of many
    aspects of the climate system are unprecedented over many centuries to many thousands
    of years. It is very likely that GHG emissions were the main driver of tropospheric
    warming and extremely likely that human-caused stratospheric ozone depletion was
    the main driver of stratospheric cooling between 1979 and the mid-1990s. It is
    virtually certain that the global upper ocean has warmed since the 1970s and extremely
    likely that human influence is the main driver. Ocean warming accounted for 91%
    of the heating in the climate system, with land warming, ice loss and atmospheric
    warming accounting for about 5%, 3% and 1%, respectively. Global mean sea level
    increased by 0.20 [0.15 to 0.25] m between 1901 and 2018. The average rate of
    sea level rise was 1.3 [0.6 to 2.1]mm yr-1 between 1901 and 1971, increasing to
    1.9 [0.8 to 2.9] mm yr-1 between 1971 and 2006, and further increasing to 3.7
    [3.2 to –4.2] mm yr -1 between 2006 and 2018. Human influence was very likely
    the main driver of these increases since at least 1971. Human influence is very
    likely the main driver of the global retreat of glaciers since the 1990s and the
    decrease in Arctic sea ice area between 1979–1988 and 2010–2019. Human influence
    has also very likely contributed to decreased Northern Hemisphere spring snow
    cover and surface melting of the Greenland ice sheet. It is virtually certain
    that human-caused CO2 emissions are the main driver of current global acidification
    of the surface open ocean.  Human-caused climate change is already affecting many
    weather and climate extremes in every region across the globe. Evidence of observed
    changes in extremes such as heatwaves, heavy precipitation, droughts, and tropical
    cyclones, and, in particular, their attribution to human influence, has strengthened
    since AR5. It is virtually certain that hot extremes have become more frequent
    and more intense across most land regions since the 1950s, while cold extremes
    have become less frequent and less severe, with high confidence that human-caused
    climate change is the main driver of these changes. Marine heatwaves have approximately
    doubled in frequency since the 1980s, and human influence has very likely contributed
    to most of them since at least 2006. The frequency and intensity of heavy precipitation
    events have increased since the 1950s over most land areas for which observational
    data are sufficient for trend analysis, and human-caused climate change is likely
    the main driver. Human-caused climate change has contributed to increases in agricultural
    and ecological droughts in some regions due to increased land evapotranspiration
    . It is likely that the global proportion of major tropical cyclone occurrence
    has increased over the last four decades.  Climate change has caused substantial
    damages, and increasingly irreversible losses, in terrestrial, freshwater, cryospheric
    and coastal and open ocean ecosystems. The extent and magnitude of climate change
    impacts are larger than estimated in previous assessments. Approximately half
    of the species assessed globally have shifted polewards or, on land, also to higher
    elevations. Biological responses including changes in geographic placement and
    shifting seasonal timing are often not sufficient to cope with recent climate
    change. Hundreds of local losses of species have been driven by increases in the
    magnitude of heat extremes and mass mortality events on land and in the ocean.
    Impacts on some ecosystems are approaching irreversibility such as the impacts
    of hydrological changes resulting from the retreat of glaciers, or the changes
    in some mountain and Arctic ecosystems driven by permafrost thaw. Impacts in ecosystems
    from slow-onset processes such as ocean acidification, sea level rise or regional
    decreases in precipitation have also been attributed to human-caused climate change.
    Climate change has contributed to desertification and exacerbated land degradation,
    particularly in low lying coastal areas, river deltas, drylands and in permafrost
    areas. Nearly 50% of coastal wetlands have been lost over the last 100 years,
    as a result of the combined effects of localised human pressures, sea level rise,
    warming and extreme climate events.  Climate change has reduced food security
    and affected water security due to warming, changing precipitation patterns, reduction
    and loss of cryospheric elements, and greater frequency and intensity of climatic
    extremes, thereby hindering efforts to meet Sustainable Development Goals. Although
    overall agricultural productivity has increased, climate change has slowed this
    growth in agricultural productivity over the past 50 years globally , with related
    negative crop yield impacts mainly recorded in mid- and low latitude regions,
    and some positive impacts in some high latitude regions. Ocean warming in the
    20th century and beyond has contributed to an overall decrease in maximum catch
    potential, compounding the impacts from overfishing for some fish stocks. Ocean
    warming and ocean acidification have adversely affected food production from shellfish
    aquaculture and fisheries in some oceanic regions . Current levels of global warming
    are associated with moderate risks from increased dryland water scarcity. Roughly
    half of the world’s population currently experiences severe water scarcity for
    at least some part of the year due to a combination of climatic and non-climatic
    drivers. Unsustainable agricultural expansion, driven in part by unbalanced diets
    , increases ecosystem and human vulnerability and leads to competition for land
    and/or water resources. Increasing weather and climate extreme events have exposed
    millions of people to acute food insecurity and reduced water security, with the
    largest impacts observed in many locations and/or communities in Africa, Asia,
    Central and South America, LDCs, Small Islands and the Arctic, and for small-scale
    food producers, low-income households and Indigenous Peoples globally.  In urban
    settings, climate change has caused adverse impacts on human health, livelihoods
    and key infrastructure. Hot extremes including heatwaves have intensified in cities
    , where they have also worsened air pollution events and limited functioning of
    key infrastructure . Urban infrastructure, including transportation, water, sanitation
    and energy systems have been compromised by extreme and slow-onset events , with
    resulting economic losses, disruptions of services and impacts to well-being.
    Observed impacts are concentrated amongst economically and socially marginalised
    urban residents, e.g., those living in informal settlements. Cities intensify
    human-caused warming locally, while urbanisation also increases mean and heavy
    precipitation over and/or downwind of cities and resulting runoff intensity .  Climate
    change has adversely affected human physical health globally and mental health
    in assessed regions, and is contributing to humanitarian crises where climate
    hazards interact with high vulnerability. In all regions increases in extreme
    heat events have resulted in human mortality and morbidity . The occurrence of
    climate-related food-borne and water-borne diseases has increased. The incidence
    of vector-borne diseases has increased from range expansion and/or increased reproduction
    of disease vectors. Animal and human diseases, including zoonoses, are emerging
    in new areas . In assessed regions, some mental health challenges are associated
    with increasing temperatures, trauma from extreme events, and loss of livelihoods
    and culture . Climate change impacts on health are mediated through natural and
    human systems, including economic and social conditions and disruptions. Climate
    and weather extremes are increasingly driving displacement in Africa, Asia, North
    America, and Central and South America , with small island states in the Caribbean
    and South Pacific being disproportionately affected relative to their small population
    size. Through displacement and involuntary migration from extreme weather and
    climate events, climate change has generated and perpetuated vulnerability .  Human
    influence has likely increased the chance of compound extreme events since the
    1950s. Concurrent and repeated climate hazards have occurred in all regions, increasing
    impacts and risks to health, ecosystems, infrastructure, livelihoods and food
    . Compound extreme events include increases in the frequency of concurrent heatwaves
    and droughts; fire weather in some regions; and compound flooding in some locations.
    Multiple risks interact, generating new sources of vulnerability to climate hazards,
    and compounding overall risk. Compound climate hazards can overwhelm adaptive
    capacity and substantially increase damage ).  Economic impacts attributable to
    climate change are increasingly affecting peoples’ livelihoods and are causing
    economic and societal impacts across national boundaries. Economic damages from
    climate change have been detected in climate-exposed sectors, with regional effects
    to agriculture, forestry, fishery, energy, and tourism, and through outdoor labour
    productivity with some exceptions of positive impacts in regions with low energy
    demand and comparative advantages in agricultural markets and tourism. Individual
    livelihoods have been affected through changes in agricultural productivity, impacts
    on human health and food security, destruction of homes and infrastructure, and
    loss of property and income, with adverse effects on gender and social equity
    . Tropical cyclones have reduced economic growth in the short-term. Event attribution
    studies and physical understanding indicate that human-caused climate change increases
    heavy precipitation associated with tropical cyclones. Wildfires in many regions
    have affected built assets, economic activity, and health. In cities and settlements,
    climate impacts to key infrastructure are leading to losses and damages across
    water and food systems, and affect economic activity, with impacts extending beyond
    the area directly impacted by the climate hazard.  Climate change has caused widespread
    adverse impacts and related losses and damages to nature and people . Losses and
    damages are unequally distributed across systems, regions and sectors. Cultural
    losses, related to tangible and intangible heritage, threaten adaptive capacity
    and may result in irrevocable losses of sense of belonging, valued cultural practices,
    identity and home, particularly for Indigenous Peoples and those more directly
    reliant on the environment for subsistence. For example, changes in snow cover,
    lake and river ice, and permafrost in many Arctic regions, are harming the livelihoods
    and cultural identity of Arctic residents including Indigenous populations. Infrastructure,
    including transportation, water, sanitation and energy systems have been compromised
    by extreme and slow-onset events, with resulting economic losses, disruptions
    of services and impacts to well-being.  Across sectors and regions, the most vulnerable
    people and systems have been disproportionately affected by the impacts of climate
    change. LDCs and SIDS who have much lower per capita emissions than the global
    average excluding CO2-LULUCF, also have high vulnerability to climatic hazards,
    with global hotspots of high human vulnerability observed in West-, Central- and
    East Africa, South Asia, Central and South America, SIDS and the Arctic. Regions
    and people with considerable development constraints have high vulnerability to
    climatic hazards. Vulnerability is higher in locations with poverty, governance
    challenges and limited access to basic services and resources, violent conflict
    and high levels of climate-sensitive livelihoods  . Vulnerability at different
    spatial levels is exacerbated by inequity and marginalisation linked to gender,
    ethnicity, low income or combinations thereof, especially for many Indigenous
    Peoples and local communities. Approximately 3.3 to 3.6 billion people live in
    contexts that are highly vulnerable to climate change. Between 2010 and 2020,
    human mortality from floods, droughts and storms was 15 times higher in highly
    vulnerable regions, compared to regions with very low vulnerability. In the Arctic
    and in some high mountain regions, negative impacts of cryosphere change have
    been especially felt among Indigenous Peoples. Human and ecosystem vulnerability
    are interdependent. Vulnerability of ecosystems and people to climate change differs
    substantially among and within regions, driven by patterns of intersecting socio-economic
    development, unsustainable ocean and land use, inequity, marginalisation, historical
    and ongoing patterns of inequity such as colonialism, and governance.
  A.3.1:
  - Adaptation Actions to Date  Progress in adaptation planning and implementation
    has been observed across all sectors and regions, generating multiple benefits.
    The ambition, scope and progress on adaptation have risen among governments at
    the local, national and international levels, along with businesses, communities
    and civil society . Various tools, measures and processes are available that can
    enable, accelerate and sustain adaptation implementation . Growing public and
    political awareness of climate impacts and risks has resulted in at least 170
    countries and many cities including adaptation in their climate policies and planning
    processes . Decision support tools and climate services are increasingly being
    used and pilot projects and local experiments are being implemented in different
    sectors .  Adaptation to water-related risks and impacts make up the majority
    of all documented adaptation. A large number of these adaptation responses are
    in the agriculture sector and these include on-farm water management, water storage,
    soil moisture conservation, and irrigation. Other adaptations in agriculture include
    cultivar improvements, agroforestry, community-based adaptation and farm and landscape
    diversification among others. For inland flooding, combinations of non-structural
    measures like early warning systems, enhancing natural water retention such as
    by restoring wetlands and rivers, and land use planning such as no build zones
    or upstream forest management, can reduce flood risk . Some land-related adaptation
    actions such as sustainable food production, improved and sustainable forest management,
    soil organic carbon management, ecosystem conservation and land restoration, reduced
    deforestation and degradation, and reduced food loss and waste are being undertaken,
    and can have mitigation co-benefits. Adaptation actions that increase the resilience
    of biodiversity and ecosystem services to climate change include responses like
    minimising additional stresses or disturbances, reducing fragmentation, increasing
    natural habitat extent, connectivity and heterogeneity, and protecting small-scale
    refugia where microclimate conditions can allow species to persist. Most innovations
    in urban adaptation have occurred through advances in disaster risk management,
    social safety nets and green/blue infrastructure. Many adaptation measures that
    benefit health and well-being are found in other sectors  .  Adaptation can generate
    multiple additional benefits such as improving agricultural productivity, innovation,
    health and well-being, food security, livelihood, and biodiversity conservation
    as well as reduction of risks and damages.  Globally tracked adaptation finance
    has shown an upward trend since AR5, but represents only a small portion of total
    climate finance, is uneven and has developed heterogeneously across regions and
    sectors. Adaptation finance has come predominantly from public sources, largely
    through grants, concessional and non-concessional instruments. Globally, private-sector
    financing of adaptation from a variety of sources such as commercial financial
    institutions, institutional investors, other private equity, non-financial corporations,
    as well as communities and households has been limited, especially in developing
    countries . Public mechanisms and finance can leverage private sector finance
    for adaptation by addressing real and perceived regulatory, cost and market barriers,
    for example via public-private partnerships. Innovations in adaptation and resilience
    finance, such as forecast-based/anticipatory financing systems and regional risk
    insurance pools, have been piloted and are growing in scale.  There are adaptation
    options which are effective in reducing climate risks 85 for specific contexts,
    sectors and regions and contribute positively to sustainable development and other
    societal goals. In the agriculture sector, cultivar improvements, on-farm water
    management and storage, soil moisture conservation, irrigation 86, agroforestry,
    community-based adaptation, and farm and landscape level diversification, and
    sustainable land management approaches, provide multiple benefits and reduce climate
    risks. Reduction of food loss and waste, and adaptation measures in support of
    balanced diets contribute to nutrition, health, and biodiversity benefits.  Ecosystem-based
    Adaptation 87 approaches such as urban greening, restoration of wetlands and upstream
    forest ecosystems reduce a range of climate change risks, including flood risks,
    urban heat and provide multiple co-benefits. Some land-based adaptation options
    provide immediate benefits ; while afforestation and reforestation, restoration
    of high-carbon ecosystems, agroforestry, and the reclamation of degraded soils
    take more time to deliver measurable results. Significant synergies exist between
    adaptation and mitigation, for example through sustainable land management approaches.
    Agroecological principles and practices and other approaches that work with natural
    processes support food security, nutrition, health and well-being, livelihoods
    and biodiversity, sustainability and ecosystem services.  Combinations of non-structural
    measures like early warning systems and structural measures like levees have reduced
    loss of lives in case of inland flooding and early warning systems along with
    flood-proofing of buildings have proven to be cost-effective in the context of
    coastal flooding under current sea level rise . Heat Health Action Plans that
    include early warning and response systems are effective adaptation options for
    extreme heat . Effective adaptation options for water, food and vector-borne diseases
    include improving access to potable water, reducing exposure of water and sanitation
    systems to extreme weather events, and improved early warning systems, surveillance,
    and vaccine development. Adaptation options such as disaster risk management,
    early warning systems, climate services and social safety nets have broad applicability
    across multiple sectors .  Integrated, multi-sectoral solutions that address social
    inequities, differentiate responses based on climate risk and cut across systems,
    increase the feasibility and effectiveness of adaptation in multiple sectors.
  A.3.2:
  - Adaptation Actions to Date  Progress in adaptation planning and implementation
    has been observed across all sectors and regions, generating multiple benefits.
    The ambition, scope and progress on adaptation have risen among governments at
    the local, national and international levels, along with businesses, communities
    and civil society . Various tools, measures and processes are available that can
    enable, accelerate and sustain adaptation implementation . Growing public and
    political awareness of climate impacts and risks has resulted in at least 170
    countries and many cities including adaptation in their climate policies and planning
    processes . Decision support tools and climate services are increasingly being
    used and pilot projects and local experiments are being implemented in different
    sectors .  Adaptation to water-related risks and impacts make up the majority
    of all documented adaptation. A large number of these adaptation responses are
    in the agriculture sector and these include on-farm water management, water storage,
    soil moisture conservation, and irrigation. Other adaptations in agriculture include
    cultivar improvements, agroforestry, community-based adaptation and farm and landscape
    diversification among others. For inland flooding, combinations of non-structural
    measures like early warning systems, enhancing natural water retention such as
    by restoring wetlands and rivers, and land use planning such as no build zones
    or upstream forest management, can reduce flood risk . Some land-related adaptation
    actions such as sustainable food production, improved and sustainable forest management,
    soil organic carbon management, ecosystem conservation and land restoration, reduced
    deforestation and degradation, and reduced food loss and waste are being undertaken,
    and can have mitigation co-benefits. Adaptation actions that increase the resilience
    of biodiversity and ecosystem services to climate change include responses like
    minimising additional stresses or disturbances, reducing fragmentation, increasing
    natural habitat extent, connectivity and heterogeneity, and protecting small-scale
    refugia where microclimate conditions can allow species to persist. Most innovations
    in urban adaptation have occurred through advances in disaster risk management,
    social safety nets and green/blue infrastructure. Many adaptation measures that
    benefit health and well-being are found in other sectors  .  Adaptation can generate
    multiple additional benefits such as improving agricultural productivity, innovation,
    health and well-being, food security, livelihood, and biodiversity conservation
    as well as reduction of risks and damages.  Globally tracked adaptation finance
    has shown an upward trend since AR5, but represents only a small portion of total
    climate finance, is uneven and has developed heterogeneously across regions and
    sectors. Adaptation finance has come predominantly from public sources, largely
    through grants, concessional and non-concessional instruments. Globally, private-sector
    financing of adaptation from a variety of sources such as commercial financial
    institutions, institutional investors, other private equity, non-financial corporations,
    as well as communities and households has been limited, especially in developing
    countries . Public mechanisms and finance can leverage private sector finance
    for adaptation by addressing real and perceived regulatory, cost and market barriers,
    for example via public-private partnerships. Innovations in adaptation and resilience
    finance, such as forecast-based/anticipatory financing systems and regional risk
    insurance pools, have been piloted and are growing in scale.  There are adaptation
    options which are effective in reducing climate risks 85 for specific contexts,
    sectors and regions and contribute positively to sustainable development and other
    societal goals. In the agriculture sector, cultivar improvements, on-farm water
    management and storage, soil moisture conservation, irrigation 86, agroforestry,
    community-based adaptation, and farm and landscape level diversification, and
    sustainable land management approaches, provide multiple benefits and reduce climate
    risks. Reduction of food loss and waste, and adaptation measures in support of
    balanced diets contribute to nutrition, health, and biodiversity benefits.  Ecosystem-based
    Adaptation 87 approaches such as urban greening, restoration of wetlands and upstream
    forest ecosystems reduce a range of climate change risks, including flood risks,
    urban heat and provide multiple co-benefits. Some land-based adaptation options
    provide immediate benefits ; while afforestation and reforestation, restoration
    of high-carbon ecosystems, agroforestry, and the reclamation of degraded soils
    take more time to deliver measurable results. Significant synergies exist between
    adaptation and mitigation, for example through sustainable land management approaches.
    Agroecological principles and practices and other approaches that work with natural
    processes support food security, nutrition, health and well-being, livelihoods
    and biodiversity, sustainability and ecosystem services.  Combinations of non-structural
    measures like early warning systems and structural measures like levees have reduced
    loss of lives in case of inland flooding and early warning systems along with
    flood-proofing of buildings have proven to be cost-effective in the context of
    coastal flooding under current sea level rise . Heat Health Action Plans that
    include early warning and response systems are effective adaptation options for
    extreme heat . Effective adaptation options for water, food and vector-borne diseases
    include improving access to potable water, reducing exposure of water and sanitation
    systems to extreme weather events, and improved early warning systems, surveillance,
    and vaccine development. Adaptation options such as disaster risk management,
    early warning systems, climate services and social safety nets have broad applicability
    across multiple sectors .  Integrated, multi-sectoral solutions that address social
    inequities, differentiate responses based on climate risk and cut across systems,
    increase the feasibility and effectiveness of adaptation in multiple sectors.
  A.3.3:
  - Adaptation Gaps and Barriers  Despite progress, adaptation gaps exist between
    current levels of adaptation and levels needed to respond to impacts and reduce
    climate risks. While progress in adaptation implementation is observed across
    all sectors and regions , many adaptation initiatives prioritise immediate and
    near-term climate risk reduction, e.g., through hard flood protection, which reduces
    the opportunity for transformational adaptation . Most observed adaptation is
    fragmented, small in scale, incremental, sector-specific, and focused more on
    planning rather than implementation. Further, observed adaptation is unequally
    distributed across regions and the largest adaptation gaps exist among lower population
    income groups. In the urban context, the largest adaptation gaps exist in projects
    that manage complex risks, for example in the food–energy–water–health nexus or
    the inter-relationships of air quality and climate risk. Many funding, knowledge
    and practice gaps remain for effective implementation, monitoring and evaluation
    and current adaptation efforts are not expected to meet existing goals. At current
    rates of adaptation planning and implementation the adaptation gap will continue
    to grow.  Soft and hard adaptation limits 100 have already been reached in some
    sectors and regions, in spite of adaptation having buffered some climate impacts.
    Ecosystems already reaching hard adaptation limits include some warm water coral
    reefs, some coastal wetlands, some rainforests, and some polar and mountain ecosystems.
    Individuals and households in low lying coastal areas in Australasia and Small
    Islands and smallholder farmers in Central and South America, Africa, Europe and
    Asia have reached soft limits, resulting from financial, governance, institutional
    and policy constraints and can be overcome by addressing these constraints. Transitioning
    from incremental to transformational adaptation can help overcome soft adaptation
    limits .  Adaptation does not prevent all losses and damages, even with effective
    adaptation and before reaching soft and hard limits. Losses and damages are unequally
    distributed across systems, regions and sectors and are not comprehensively addressed
    by current financial, governance and institutional arrangements, particularly
    in vulnerable developing countries.  There is increased evidence of maladaptation
    in various sectors and regions. Examples of maladaptation are observed in urban
    areas , agriculture , ecosystems (e.g. fire suppression in naturally
  A.3.6:
  - Adaptation Gaps and Barriers  Despite progress, adaptation gaps exist between
    current levels of adaptation and levels needed to respond to impacts and reduce
    climate risks. While progress in adaptation implementation is observed across
    all sectors and regions , many adaptation initiatives prioritise immediate and
    near-term climate risk reduction, e.g., through hard flood protection, which reduces
    the opportunity for transformational adaptation . Most observed adaptation is
    fragmented, small in scale, incremental, sector-specific, and focused more on
    planning rather than implementation. Further, observed adaptation is unequally
    distributed across regions and the largest adaptation gaps exist among lower population
    income groups. In the urban context, the largest adaptation gaps exist in projects
    that manage complex risks, for example in the food–energy–water–health nexus or
    the inter-relationships of air quality and climate risk. Many funding, knowledge
    and practice gaps remain for effective implementation, monitoring and evaluation
    and current adaptation efforts are not expected to meet existing goals. At current
    rates of adaptation planning and implementation the adaptation gap will continue
    to grow.  Soft and hard adaptation limits 100 have already been reached in some
    sectors and regions, in spite of adaptation having buffered some climate impacts.
    Ecosystems already reaching hard adaptation limits include some warm water coral
    reefs, some coastal wetlands, some rainforests, and some polar and mountain ecosystems.
    Individuals and households in low lying coastal areas in Australasia and Small
    Islands and smallholder farmers in Central and South America, Africa, Europe and
    Asia have reached soft limits, resulting from financial, governance, institutional
    and policy constraints and can be overcome by addressing these constraints. Transitioning
    from incremental to transformational adaptation can help overcome soft adaptation
    limits .  Adaptation does not prevent all losses and damages, even with effective
    adaptation and before reaching soft and hard limits. Losses and damages are unequally
    distributed across systems, regions and sectors and are not comprehensively addressed
    by current financial, governance and institutional arrangements, particularly
    in vulnerable developing countries.  There is increased evidence of maladaptation
    in various sectors and regions. Examples of maladaptation are observed in urban
    areas , agriculture , ecosystems (e.g. fire suppression in naturally
  - 'Lack of Finance as a Barrier to Climate Action  Insufficient financing, and a
    lack of political frameworks and incentives for finance, are key causes of the
    implementation gaps for both mitigation and adaptation. Financial flows remained
    heavily focused on mitigation, are uneven, and have developed heterogeneously
    across regions and sectors. In 2018, public and publicly mobilised private climate
    finance flows from developed to developing countries were below the collective
    goal under the UNFCCC and Paris Agreement to mobilise USD 100 billion per year
    by 2020 in the context of meaningful mitigation action and transparency on implementation
    . Public and private finance flows for fossil fuels are still greater than those
    for climate adaptation and mitigation . The overwhelming majority of tracked climate
    finance is directed towards mitigation. Nevertheless, average annual modelled
    investment requirements for 2020 to 2030 in scenarios that limit warming to 2°C
    or 1.5°C are a factor of three to six greater than current levels, and total mitigation
    investments would need to increase across all sectors and regions. Challenges
    remain for green bonds and similar products, in particular around integrity and
    additionality, as well as the limited applicability of these markets to many developing
    countries.  Current global financial flows for adaptation including from public
    and private finance sources, are insufficient for and constrain implementation
    of adaptation options, especially in developing countries. There are widening
    disparities between the estimated costs of adaptation and the documented finance
    allocated to adaptation. Adaptation finance needs are estimated to be higher than
    those assessed in AR5, and the enhanced mobilisation of and access to financial
    resources are essential for implementation of adaptation and to reduce adaptation
    gaps. Annual finance flows targeting adaptation for Africa, for example, are billions
    of USD less than the lowest adaptation cost estimates for near-term climate change.
    Adverse climate impacts can further reduce the availability of financial resources
    by causing losses and damages and impeding national economic growth, thereby further
    increasing financial constraints for adaptation particularly for developing countries
    and LDCs.  Without effective mitigation and adaptation, losses and damages will
    continue to disproportionately affect the poorest and most vulnerable populations.
    Accelerated financial support for developing countries from developed countries
    and other sources is a critical enabler to enhance mitigation action . Many developing
    countries lack comprehensive data at the scale needed and lack adequate financial
    resources needed for adaptation for reducing associated economic and non-economic
    losses and damages.  There are barriers to redirecting capital towards climate
    action both within and outside the global financial sector. These barriers include:
    the inadequate assessment of climate-related risks and investment opportunities,
    regional mismatch between available capital and investment needs, home bias factors,
    country indebtedness levels, economic vulnerability, and limited institutional
    capacities. Challenges from outside the financial sector include: limited local
    capital markets; unattractive risk-return profiles, in particular due to missing
    or weak regulatory environments that are inconsistent with ambition levels; limited
    institutional capacity to ensure safeguards; standardisation, aggregation, scalability
    and replicability of investment opportunities and financing models; and, a pipeline
    ready for commercial investments.'
  A.4.1:
  - Global Policy Setting  The United Nations Framework Convention on Climate Change,
    Kyoto Protocol, and Paris Agreement are supporting rising levels of national ambition
    and encouraging the development and implementation of climate policies at multiple
    levels of governance. The Kyoto Protocol led to reduced emissions in some countries
    and was instrumental in building national and international capacity for GHG reporting,
    accounting and emissions markets . The Paris Agreement, adopted under the UNFCCC,
    with near universal participation, has led to policy development and target-setting
    at national and sub-national levels, particularly in relation to mitigation but
    also for adaptation, as well as enhanced transparency of climate action and support.
    Nationally Determined Contributions, required under the Paris Agreement, have
    required countries to articulate their priorities and ambition with respect to
    climate action.  Loss & Damage was formally recognized in 2013 through establishment
    of the Warsaw International Mechanism on Loss and Damage, and in 2015, Article
    8 of the Paris Agreement provided a legal basis for the WIM. There is improved
    understanding of both economic and non-economic losses and damages, which is informing
    international climate policy and which has highlighted that losses and damages
    are not comprehensively addressed by current financial, governance and institutional
    arrangements, particularly in vulnerable developing countries .  Other recent
    global agreements that influence responses to climate change include the Sendai
    Framework for Disaster Risk Reduction , the finance-oriented Addis Ababa Action
    Agenda and the New Urban Agenda, and the Kigali Amendment to the Montreal Protocol
    on Substances that Deplete the Ozone Layer , among others. In addition, the 2030
    Agenda for Sustainable Development, adopted in 2015 by UN member states, sets
    out 17 Sustainable Development Goals and seeks to align efforts globally to prioritise
    ending extreme poverty, protect the planet and promote more peaceful, prosperous
    and inclusive societies. If achieved, these agreements would reduce climate change,
    and the impacts on health, well-being, migration, and conflict, among others .  Since
    AR5, rising public awareness and an increasing diversity of actors, have overall
    helped accelerate political commitment and global efforts to address climate change.
    Mass social movements have emerged as catalysing agents in some regions, often
    building on prior movements including Indigenous Peoples-led movements, youth
    movements, human rights movements, gender activism, and climate litigation, which
    is raising awareness and, in some cases, has influenced the outcome and ambition
    of climate governance. Engaging Indigenous Peoples and local communities using
    just-transition and rights-based decision-making approaches, implemented through
    collective and participatory decision-making processes has enabled deeper ambition
    and accelerated action in different ways, and at all scales, depending on national
    circumstances. The media helps shape the public discourse about climate change.
    This can usefully build public support to accelerate climate action . In some
    instances, public discourses of media and organised counter movements have impeded
    climate action, exacerbating helplessness and disinformation and fuelling polarisation,
    with negative implications for climate action .
  - Mitigation Actions to Date  There has been a consistent expansion of policies
    and laws addressing mitigation since AR5. Climate governance supports mitigation
    by providing frameworks through which diverse actors interact, and a basis for
    policy development and implementation. Many regulatory and economic instruments
    have already been deployed successfully. By 2020, laws primarily focussed on reducing
    GHG emissions existed in 56 countries covering 53% of global emissions. The application
    of diverse policy instruments for mitigation at the national and sub-national
    levels has grown consistently across a range of sectors. Policy coverage is uneven
    across sectors and remains limited for emissions from agriculture, and from industrial
    materials and feedstocks.  Practical experience has informed economic instrument
    design and helped to improve predictability, environmental effectiveness, economic
    efficiency, alignment with distributional goals, and social acceptance. Low-emission
    technological innovation is strengthened through the combination of technology-push
    policies, together with policies that create incentives for behaviour change and
    market opportunities. Comprehensive and consistent policy packages have been found
    to be more effective than single policies. Combining mitigation with policies
    to shift development pathways, policies that induce lifestyle or behaviour changes,
    for example, measures promoting walkable urban areas combined with electrification
    and renewable energy can create health co-benefits from cleaner air and enhanced
    active mobility . Climate governance enables mitigation by providing an overall
    direction, setting targets, mainstreaming climate action across policy domains
    and levels, based on national circumstances and in the context of international
    cooperation. Effective governance enhances regulatory certainty, creating specialised
    organisations and creating the context to mobilise finance. These functions can
    be promoted by climate-relevant laws, which are growing in number, or climate
    strategies, among others, based on national and sub-national context. Effective
    and equitable climate governance builds on engagement with civil society actors,
    political actors, businesses, youth, labour, media, Indigenous Peoples and local
    communities.  The unit costs of several low-emission technologies, including solar,
    wind and lithium-ion batteries, have fallen consistently since 2010. Design and
    process innovations in combination with the use of digital technologies have led
    to near-commercial availability of many low or zero emissions options in buildings,
    transport and industry. From 2010-2019, there have been sustained decreases in
    the unit costs of solar energy , wind energy, and lithium-ion batteries, and large
    increases in their deployment, e.g., >10× for solar and >100× for electric vehicles,
    albeit varying widely across regions. Electricity from PV and wind is now cheaper
    than electricity from fossil sources in many regions, electric vehicles are increasingly
    competitive with internal combustion engines, and large-scale battery storage
    on electricity grids is increasingly viable. In comparison to modular small-unit
    size technologies, the empirical record shows that multiple large-scale mitigation
    technologies, with fewer opportunities for learning, have seen minimal cost reductions
    and their adoption has grown slowly. Maintaining emission-intensive systems may,
    in some regions and sectors, be more expensive than transitioning to low emission
    systems.  For almost all basic materials – primary metals, building materials
    and chemicals – many low- to zero-GHG intensity production processes are at the
    pilot to near-commercial and in some cases commercial stage but they are not yet
    established industrial practice. Integrated design in construction and retrofit
    of buildings has led to increasing examples of zero energy or zero carbon buildings.
    Technological innovation made possible the widespread adoption of LED lighting.
    Digital technologies including sensors, the internet of things, robotics, and
    artificial intelligence can improve energy management in all sectors; they can
    increase energy efficiency, and promote the adoption of many low-emission technologies,
    including decentralised renewable energy, while creating economic opportunities.
    However, some of these climate change mitigation gains can be reduced or counterbalanced
    by growth in demand for goods and services due to the use of digital devices.
    Several mitigation options, notably solar energy, wind energy, electrification
    of urban systems, urban green infrastructure, energy efficiency, demand side management,
    improved forest- and crop/grassland management, and reduced food waste and loss,
    are technically viable, are becoming increasingly cost effective and are generally
    supported by the public, and this enables expanded deployment in many regions.  The
    magnitude of global climate finance flows has increased and financing channels
    have broadened. Annual tracked total financial flows for climate mitigation and
    adaptation increased by up to 60% between 2013/14 and 2019/20, but average growth
    has slowed since 2018 and most climate finance stays within national borders.
    Markets for green bonds, environmental, social and governance and sustainable
    finance products have expanded significantly since AR5 . Investors, central banks,
    and financial regulators are driving increased awareness of climate risk to support
    climate policy development and implementation. Accelerated international financial
    cooperation is a critical enabler of low-GHG and just transitions.  Economic instruments
    have been effective in reducing emissions, complemented by regulatory instruments
    mainly at the national and also sub-national and regional level. By 2020, over
    20% of global GHG emissions were covered by carbon taxes or emissions trading
    systems, although coverage and prices have been insufficient to achieve deep reductions.
    Equity and distributional impacts of carbon pricing instruments can be addressed
    by using revenue from carbon taxes or emissions trading to support low-income
    households, among other approaches. The mix of policy instruments which reduced
    costs and stimulated adoption of solar energy, wind energy and lithium-ion batteries
    includes public R&D, funding for demonstration and pilot projects, and demand-pull
    instruments such as deployment subsidies to attain scale .  Mitigation actions,
    supported by policies, have contributed to a decrease in global energy and carbon
    intensity between 2010 and 2019, with a growing number of countries achieving
    absolute GHG emission reductions for more than a decade . While global net GHG
    emissions have increased since 2010, global energy intensity decreased by 2% yr
    –1 between 2010 and 2019. Global carbon intensity also decreased by 0.3% yr –1
    , mainly due to fuel switching from coal to gas, reduced expansion of coal capacity,
    and increased use of renewables, and with large regional variations over the same
    period. In many countries, policies have enhanced energy efficiency, reduced rates
    of deforestation and accelerated technology deployment, leading to avoided and
    in some cases reduced or removed emissions. At least 18 countries have sustained
    production-based CO2 and GHG and consumption-based CO2 absolute emission reductions
    for longer than 10 years since 2005 through energy supply decarbonization, energy
    efficiency gains, and energy demand reduction, which resulted from both policies
    and changes in economic structure. Some countries have reduced production-based
    GHG emissions by a third or more since peaking, and some have achieved reduction
    rates of around 4% yr–1 for several years consecutively. Multiple lines of evidence
    suggest that mitigation policies have led to avoided global emissions of several
    GtCO 2-eq yr–1. At least 1.8 GtCO2-eq yr–1 of avoided emissions can be accounted
    for by aggregating separate estimates for the effects of economic and regulatory
    instruments. Growing numbers of laws and executive orders have impacted global
    emissions and are estimated to have resulted in 5.9 GtCO2 -eq yr–1 of avoided
    emissions in 2016. These reductions have only partly offset global emissions growth.
  A.4.2:
  - Mitigation Actions to Date  There has been a consistent expansion of policies
    and laws addressing mitigation since AR5. Climate governance supports mitigation
    by providing frameworks through which diverse actors interact, and a basis for
    policy development and implementation. Many regulatory and economic instruments
    have already been deployed successfully. By 2020, laws primarily focussed on reducing
    GHG emissions existed in 56 countries covering 53% of global emissions. The application
    of diverse policy instruments for mitigation at the national and sub-national
    levels has grown consistently across a range of sectors. Policy coverage is uneven
    across sectors and remains limited for emissions from agriculture, and from industrial
    materials and feedstocks.  Practical experience has informed economic instrument
    design and helped to improve predictability, environmental effectiveness, economic
    efficiency, alignment with distributional goals, and social acceptance. Low-emission
    technological innovation is strengthened through the combination of technology-push
    policies, together with policies that create incentives for behaviour change and
    market opportunities. Comprehensive and consistent policy packages have been found
    to be more effective than single policies. Combining mitigation with policies
    to shift development pathways, policies that induce lifestyle or behaviour changes,
    for example, measures promoting walkable urban areas combined with electrification
    and renewable energy can create health co-benefits from cleaner air and enhanced
    active mobility . Climate governance enables mitigation by providing an overall
    direction, setting targets, mainstreaming climate action across policy domains
    and levels, based on national circumstances and in the context of international
    cooperation. Effective governance enhances regulatory certainty, creating specialised
    organisations and creating the context to mobilise finance. These functions can
    be promoted by climate-relevant laws, which are growing in number, or climate
    strategies, among others, based on national and sub-national context. Effective
    and equitable climate governance builds on engagement with civil society actors,
    political actors, businesses, youth, labour, media, Indigenous Peoples and local
    communities.  The unit costs of several low-emission technologies, including solar,
    wind and lithium-ion batteries, have fallen consistently since 2010. Design and
    process innovations in combination with the use of digital technologies have led
    to near-commercial availability of many low or zero emissions options in buildings,
    transport and industry. From 2010-2019, there have been sustained decreases in
    the unit costs of solar energy , wind energy, and lithium-ion batteries, and large
    increases in their deployment, e.g., >10× for solar and >100× for electric vehicles,
    albeit varying widely across regions. Electricity from PV and wind is now cheaper
    than electricity from fossil sources in many regions, electric vehicles are increasingly
    competitive with internal combustion engines, and large-scale battery storage
    on electricity grids is increasingly viable. In comparison to modular small-unit
    size technologies, the empirical record shows that multiple large-scale mitigation
    technologies, with fewer opportunities for learning, have seen minimal cost reductions
    and their adoption has grown slowly. Maintaining emission-intensive systems may,
    in some regions and sectors, be more expensive than transitioning to low emission
    systems.  For almost all basic materials – primary metals, building materials
    and chemicals – many low- to zero-GHG intensity production processes are at the
    pilot to near-commercial and in some cases commercial stage but they are not yet
    established industrial practice. Integrated design in construction and retrofit
    of buildings has led to increasing examples of zero energy or zero carbon buildings.
    Technological innovation made possible the widespread adoption of LED lighting.
    Digital technologies including sensors, the internet of things, robotics, and
    artificial intelligence can improve energy management in all sectors; they can
    increase energy efficiency, and promote the adoption of many low-emission technologies,
    including decentralised renewable energy, while creating economic opportunities.
    However, some of these climate change mitigation gains can be reduced or counterbalanced
    by growth in demand for goods and services due to the use of digital devices.
    Several mitigation options, notably solar energy, wind energy, electrification
    of urban systems, urban green infrastructure, energy efficiency, demand side management,
    improved forest- and crop/grassland management, and reduced food waste and loss,
    are technically viable, are becoming increasingly cost effective and are generally
    supported by the public, and this enables expanded deployment in many regions.  The
    magnitude of global climate finance flows has increased and financing channels
    have broadened. Annual tracked total financial flows for climate mitigation and
    adaptation increased by up to 60% between 2013/14 and 2019/20, but average growth
    has slowed since 2018 and most climate finance stays within national borders.
    Markets for green bonds, environmental, social and governance and sustainable
    finance products have expanded significantly since AR5 . Investors, central banks,
    and financial regulators are driving increased awareness of climate risk to support
    climate policy development and implementation. Accelerated international financial
    cooperation is a critical enabler of low-GHG and just transitions.  Economic instruments
    have been effective in reducing emissions, complemented by regulatory instruments
    mainly at the national and also sub-national and regional level. By 2020, over
    20% of global GHG emissions were covered by carbon taxes or emissions trading
    systems, although coverage and prices have been insufficient to achieve deep reductions.
    Equity and distributional impacts of carbon pricing instruments can be addressed
    by using revenue from carbon taxes or emissions trading to support low-income
    households, among other approaches. The mix of policy instruments which reduced
    costs and stimulated adoption of solar energy, wind energy and lithium-ion batteries
    includes public R&D, funding for demonstration and pilot projects, and demand-pull
    instruments such as deployment subsidies to attain scale .  Mitigation actions,
    supported by policies, have contributed to a decrease in global energy and carbon
    intensity between 2010 and 2019, with a growing number of countries achieving
    absolute GHG emission reductions for more than a decade . While global net GHG
    emissions have increased since 2010, global energy intensity decreased by 2% yr
    –1 between 2010 and 2019. Global carbon intensity also decreased by 0.3% yr –1
    , mainly due to fuel switching from coal to gas, reduced expansion of coal capacity,
    and increased use of renewables, and with large regional variations over the same
    period. In many countries, policies have enhanced energy efficiency, reduced rates
    of deforestation and accelerated technology deployment, leading to avoided and
    in some cases reduced or removed emissions. At least 18 countries have sustained
    production-based CO2 and GHG and consumption-based CO2 absolute emission reductions
    for longer than 10 years since 2005 through energy supply decarbonization, energy
    efficiency gains, and energy demand reduction, which resulted from both policies
    and changes in economic structure. Some countries have reduced production-based
    GHG emissions by a third or more since peaking, and some have achieved reduction
    rates of around 4% yr–1 for several years consecutively. Multiple lines of evidence
    suggest that mitigation policies have led to avoided global emissions of several
    GtCO 2-eq yr–1. At least 1.8 GtCO2-eq yr–1 of avoided emissions can be accounted
    for by aggregating separate estimates for the effects of economic and regulatory
    instruments. Growing numbers of laws and executive orders have impacted global
    emissions and are estimated to have resulted in 5.9 GtCO2 -eq yr–1 of avoided
    emissions in 2016. These reductions have only partly offset global emissions growth.
  A.4.3:
  - The Gap Between Mitigation Policies, Pledges and  Pathways that Limit Warming
    to 1.5°C or Below 2°C Global GHG emissions in 2030 associated with the implementation
    of NDCs announced prior to COP2691 would make it likely that warming will exceed
    1.5°C during the 21st century and would make it harder to limit warming below
    2°C – if no additional commitments are made or actions taken. A substantial ‘emissions
    gap’ exists as global GHG emissions in 2030 associated with the implementation
    of NDCs announced prior to COP26 would be similar to or only slightly below 2019
    emission levels and higher than those associated with modelled mitigation pathways
    that limit warming to 1.5°C with no or limited overshoot or to 2°C, assuming immediate
    action, which implies deep, rapid, and sustained global GHG emission reductions
    this decade  . 92 The magnitude of the emissions gap depends on the global warming
    level considered and whether only unconditional or also conditional elements of
    NDCs 93 are considered . Modelled pathways that are consistent with NDCs announced
    prior to COP26 until 2030 and assume no increase in ambition thereafter have higher
    emissions, leading to a median global warming of 2.8 [2.1 to 3.4]°C by 2100 .
    If the ‘emission gap’ is not reduced, global GHG emissions in 2030 consistent
    with NDCs announced prior to COP26 make it likely that warming will exceed 1.5°C
    during the 21st century, while limiting warming to 2°C would imply an unprecedented
    acceleration of mitigation efforts during 2030–2050 .  Policies implemented by
    the end of 2020 are projected to result in higher global GHG emissions in 2030
    than those implied by NDCs, indicating an ‘implementation gap 94 ’ . Projected
    global emissions implied by policies implemented by the end of 2020 are 57 GtCO2
    -eq in 2030. This points to an implementation gap compared with the NDCs of 4
    to 7 GtCO 2-eq in 2030; without a strengthening of policies, emissions are projected
    to rise, leading to a median global warming of 2.2°C to 3.5°C by 2100 .  Projected
    cumulative future CO2 emissions over the lifetime of existing fossil fuel infrastructure
    without additional abatement exceed the total cumulative net CO2 emissions in
    pathways that limit warming to 1.5°C with no or limited overshoot. They are approximately
    equal to total cumulative net CO2 emissions in pathways that limit warming to
    2°C with a likelihood of 83% 96. Limiting warming to 2°C or lower will result
    in stranded assets. About 80% of coal, 50% of gas, and 30% of oil reserves cannot
    be burned and emitted if warming is limited to 2°C. Significantly more reserves
    are expected to remain unburned if warming is limited to 1.5°C.  Many countries
    have signalled an intention to achieve net zero GHG or net zero CO 2 emissions
    by around mid-century . More than 100 countries have either adopted, announced
    or are discussing net zero GHG or net zero CO 2 emissions commitments, covering
    more than two-thirds of global GHG emissions. A growing number of cities are setting
    climate targets, including net zero GHG targets. Many companies and institutions
    have also announced net zero emissions targets in recent years. The various net
    zero emission pledges differ across countries in terms of scope and specificity,
    and limited policies are to date in place to deliver on them.  All mitigation
    strategies face implementation challenges, including technology risks, scaling,
    and costs. Almost all mitigation options also face institutional barriers that
    need to be addressed to enable their application at scale . Current development
    pathways may create behavioural, spatial, economic and social barriers to accelerated
    mitigation at all scales. Choices made by policymakers, citizens, the private
    sector and other stakeholders influence societies’ development pathways. Structural
    factors of national circumstances and capabilities  affect the breadth and depth
    of climate governance. The extent to which civil society actors, political actors,
    businesses, youth, labour, media, Indigenous Peoples, and local communities are
    engaged influences political support for climate change mitigation and eventual
    policy outcomes.  The adoption of low-emission technologies lags in most developing
    countries, particularly least developed ones, due in part to weaker enabling conditions,
    including limited finance, technology development and transfer, and capacity .
    In many countries, especially those with limited institutional capacity, several
    adverse side-effects have been observed as a result of diffusion of low-emission
    technology, e.g., low-value employment, and dependency on foreign knowledge and
    suppliers. Low-emission innovation along with strengthened enabling conditions
    can reinforce development benefits, which can, in turn, create feedbacks towards
    greater public support for policy. Persistent and region-specific barriers also
    continue to hamper the economic and political feasibility of deploying AFOLU mitigation
    options. Barriers to implementation of AFOLU mitigation include insufficient institutional
    and financial support, uncertainty over long-term additionality and trade-offs,
    weak governance, insecure land ownership, low incomes and the lack of access to
    alternative sources of income, and the risk of reversal .
  - 'The Timing and Urgency of Climate Action  The magnitude and rate of climate change
    and associated risks depend strongly on near-term mitigation and adaptation actions
    . Global warming is more likely than not to reach 1.5°C between 2021 and 2040
    even under the very low GHG emission scenarios, and likely or very likely to exceed
    1.5°C under higher emissions scenarios 141. Many adaptation options have medium
    or high feasibility up to 1.5°C , but hard limits to adaptation have already been
    reached in some ecosystems and the effectiveness of adaptation to reduce climate
    risk will decrease with increasing warming. Societal choices and actions implemented
    in this decade determine the extent to which medium- and long-term pathways will
    deliver higher or lower climate resilient development. Climate resilient development
    prospects are increasingly limited if current greenhouse gas emissions do not
    rapidly decline, especially if 1.5°C global warming is exceeded in the near term.
    Without urgent, effective and equitable adaptation and mitigation actions, climate
    change increasingly threatens the health and livelihoods of people around the
    globe, ecosystem health, and biodiversity, with severe adverse consequences for
    current and future generations. .  In modelled pathways that limit warming to
    1.5°C with no or limited overshoot and in those that limit warming to 2°C, assuming
    immediate actions, global GHG emissions are projected to peak in the early 2020s
    followed by rapid and deep GHG emissions reductions 142 . In pathways that limit
    warming to 1.5°C with no or limited overshoot, net global GHG emissions are projected
    to fall by 43 [34 to 60]%143 below 2019 levels by 2030, 60 [49 to 77]% by 2035,
    69 [58 to 90]% by 2040 and 84 [73 to 98]% by 2050 144. Global modelled pathways
    that limit warming to 2°C have reductions in GHG emissions below 2019 levels of
    21 [1 to 42]% by 2030, 35 [22 to 55] % by 2035, 46 [34 to 63] % by 2040 and 64
    [53 to 77]% by 2050145. Global GHG emissions associated with NDCs announced prior
    to COP26 would make it likely that warming would exceed 1.5°C and limiting warming
    to 2°C would then imply a rapid acceleration of emission reductions during 2030–2050,
    around 70% faster than in pathways where immediate action is taken to limit warming
    to 2°C Continued investments in unabated high-emitting infrastructure and limited
    development and deployment of low-emitting alternatives prior to 2030 would act
    as barriers to this acceleration and increase feasibility risks.  All global modelled
    pathways that limit warming to 2°C or lower by 2100 involve reductions in both
    net CO 2 emissions and non-CO 2 emissions. For example, in pathways that limit
    warming to 1.5°C with no or limited overshoot, global CH4 emissions are reduced
    by 34 [21 to 57]% below 2019 levels by 2030 and by 44 [31 to 63]% in 2040. Global
    CH 4 emissions are reduced by 24 [9 to 53]% below 2019 levels by 2030 and by 37
    [20 to 60]% in 2040 in modelled pathways that limit warming to 2°C with action
    starting in 2020.  All global modelled pathways that limit warming to 2°C or lower
    by 2100 involve GHG emission reductions in all sectors . The contributions of
    different sectors vary across modelled mitigation pathways. In most global modelled
    mitigation pathways, emissions from land-use, land-use change and forestry, via
    reforestation and reduced deforestation, and from the energy supply sector reach
    net zero CO2 emissions earlier than the buildings, industry and transport sectors.
    Strategies can rely on combinations of different options, but doing less in one
    sector needs to be compensated by further reductions in other sectors if warming
    is to be limited.  Without rapid, deep and sustained mitigation and accelerated
    adaptation actions, losses and damages will continue to increase, including projected
    adverse impacts in Africa, LDCs, SIDS, Central and South America , Asia and the
    Arctic, and will disproportionately affect the most vulnerable populations .  '
  A.4.4:
  - Mitigation Actions to Date  There has been a consistent expansion of policies
    and laws addressing mitigation since AR5. Climate governance supports mitigation
    by providing frameworks through which diverse actors interact, and a basis for
    policy development and implementation. Many regulatory and economic instruments
    have already been deployed successfully. By 2020, laws primarily focussed on reducing
    GHG emissions existed in 56 countries covering 53% of global emissions. The application
    of diverse policy instruments for mitigation at the national and sub-national
    levels has grown consistently across a range of sectors. Policy coverage is uneven
    across sectors and remains limited for emissions from agriculture, and from industrial
    materials and feedstocks.  Practical experience has informed economic instrument
    design and helped to improve predictability, environmental effectiveness, economic
    efficiency, alignment with distributional goals, and social acceptance. Low-emission
    technological innovation is strengthened through the combination of technology-push
    policies, together with policies that create incentives for behaviour change and
    market opportunities. Comprehensive and consistent policy packages have been found
    to be more effective than single policies. Combining mitigation with policies
    to shift development pathways, policies that induce lifestyle or behaviour changes,
    for example, measures promoting walkable urban areas combined with electrification
    and renewable energy can create health co-benefits from cleaner air and enhanced
    active mobility . Climate governance enables mitigation by providing an overall
    direction, setting targets, mainstreaming climate action across policy domains
    and levels, based on national circumstances and in the context of international
    cooperation. Effective governance enhances regulatory certainty, creating specialised
    organisations and creating the context to mobilise finance. These functions can
    be promoted by climate-relevant laws, which are growing in number, or climate
    strategies, among others, based on national and sub-national context. Effective
    and equitable climate governance builds on engagement with civil society actors,
    political actors, businesses, youth, labour, media, Indigenous Peoples and local
    communities.  The unit costs of several low-emission technologies, including solar,
    wind and lithium-ion batteries, have fallen consistently since 2010. Design and
    process innovations in combination with the use of digital technologies have led
    to near-commercial availability of many low or zero emissions options in buildings,
    transport and industry. From 2010-2019, there have been sustained decreases in
    the unit costs of solar energy , wind energy, and lithium-ion batteries, and large
    increases in their deployment, e.g., >10× for solar and >100× for electric vehicles,
    albeit varying widely across regions. Electricity from PV and wind is now cheaper
    than electricity from fossil sources in many regions, electric vehicles are increasingly
    competitive with internal combustion engines, and large-scale battery storage
    on electricity grids is increasingly viable. In comparison to modular small-unit
    size technologies, the empirical record shows that multiple large-scale mitigation
    technologies, with fewer opportunities for learning, have seen minimal cost reductions
    and their adoption has grown slowly. Maintaining emission-intensive systems may,
    in some regions and sectors, be more expensive than transitioning to low emission
    systems.  For almost all basic materials – primary metals, building materials
    and chemicals – many low- to zero-GHG intensity production processes are at the
    pilot to near-commercial and in some cases commercial stage but they are not yet
    established industrial practice. Integrated design in construction and retrofit
    of buildings has led to increasing examples of zero energy or zero carbon buildings.
    Technological innovation made possible the widespread adoption of LED lighting.
    Digital technologies including sensors, the internet of things, robotics, and
    artificial intelligence can improve energy management in all sectors; they can
    increase energy efficiency, and promote the adoption of many low-emission technologies,
    including decentralised renewable energy, while creating economic opportunities.
    However, some of these climate change mitigation gains can be reduced or counterbalanced
    by growth in demand for goods and services due to the use of digital devices.
    Several mitigation options, notably solar energy, wind energy, electrification
    of urban systems, urban green infrastructure, energy efficiency, demand side management,
    improved forest- and crop/grassland management, and reduced food waste and loss,
    are technically viable, are becoming increasingly cost effective and are generally
    supported by the public, and this enables expanded deployment in many regions.  The
    magnitude of global climate finance flows has increased and financing channels
    have broadened. Annual tracked total financial flows for climate mitigation and
    adaptation increased by up to 60% between 2013/14 and 2019/20, but average growth
    has slowed since 2018 and most climate finance stays within national borders.
    Markets for green bonds, environmental, social and governance and sustainable
    finance products have expanded significantly since AR5 . Investors, central banks,
    and financial regulators are driving increased awareness of climate risk to support
    climate policy development and implementation. Accelerated international financial
    cooperation is a critical enabler of low-GHG and just transitions.  Economic instruments
    have been effective in reducing emissions, complemented by regulatory instruments
    mainly at the national and also sub-national and regional level. By 2020, over
    20% of global GHG emissions were covered by carbon taxes or emissions trading
    systems, although coverage and prices have been insufficient to achieve deep reductions.
    Equity and distributional impacts of carbon pricing instruments can be addressed
    by using revenue from carbon taxes or emissions trading to support low-income
    households, among other approaches. The mix of policy instruments which reduced
    costs and stimulated adoption of solar energy, wind energy and lithium-ion batteries
    includes public R&D, funding for demonstration and pilot projects, and demand-pull
    instruments such as deployment subsidies to attain scale .  Mitigation actions,
    supported by policies, have contributed to a decrease in global energy and carbon
    intensity between 2010 and 2019, with a growing number of countries achieving
    absolute GHG emission reductions for more than a decade . While global net GHG
    emissions have increased since 2010, global energy intensity decreased by 2% yr
    –1 between 2010 and 2019. Global carbon intensity also decreased by 0.3% yr –1
    , mainly due to fuel switching from coal to gas, reduced expansion of coal capacity,
    and increased use of renewables, and with large regional variations over the same
    period. In many countries, policies have enhanced energy efficiency, reduced rates
    of deforestation and accelerated technology deployment, leading to avoided and
    in some cases reduced or removed emissions. At least 18 countries have sustained
    production-based CO2 and GHG and consumption-based CO2 absolute emission reductions
    for longer than 10 years since 2005 through energy supply decarbonization, energy
    efficiency gains, and energy demand reduction, which resulted from both policies
    and changes in economic structure. Some countries have reduced production-based
    GHG emissions by a third or more since peaking, and some have achieved reduction
    rates of around 4% yr–1 for several years consecutively. Multiple lines of evidence
    suggest that mitigation policies have led to avoided global emissions of several
    GtCO 2-eq yr–1. At least 1.8 GtCO2-eq yr–1 of avoided emissions can be accounted
    for by aggregating separate estimates for the effects of economic and regulatory
    instruments. Growing numbers of laws and executive orders have impacted global
    emissions and are estimated to have resulted in 5.9 GtCO2 -eq yr–1 of avoided
    emissions in 2016. These reductions have only partly offset global emissions growth.
  - The Gap Between Mitigation Policies, Pledges and  Pathways that Limit Warming
    to 1.5°C or Below 2°C Global GHG emissions in 2030 associated with the implementation
    of NDCs announced prior to COP2691 would make it likely that warming will exceed
    1.5°C during the 21st century and would make it harder to limit warming below
    2°C – if no additional commitments are made or actions taken. A substantial ‘emissions
    gap’ exists as global GHG emissions in 2030 associated with the implementation
    of NDCs announced prior to COP26 would be similar to or only slightly below 2019
    emission levels and higher than those associated with modelled mitigation pathways
    that limit warming to 1.5°C with no or limited overshoot or to 2°C, assuming immediate
    action, which implies deep, rapid, and sustained global GHG emission reductions
    this decade  . 92 The magnitude of the emissions gap depends on the global warming
    level considered and whether only unconditional or also conditional elements of
    NDCs 93 are considered . Modelled pathways that are consistent with NDCs announced
    prior to COP26 until 2030 and assume no increase in ambition thereafter have higher
    emissions, leading to a median global warming of 2.8 [2.1 to 3.4]°C by 2100 .
    If the ‘emission gap’ is not reduced, global GHG emissions in 2030 consistent
    with NDCs announced prior to COP26 make it likely that warming will exceed 1.5°C
    during the 21st century, while limiting warming to 2°C would imply an unprecedented
    acceleration of mitigation efforts during 2030–2050 .  Policies implemented by
    the end of 2020 are projected to result in higher global GHG emissions in 2030
    than those implied by NDCs, indicating an ‘implementation gap 94 ’ . Projected
    global emissions implied by policies implemented by the end of 2020 are 57 GtCO2
    -eq in 2030. This points to an implementation gap compared with the NDCs of 4
    to 7 GtCO 2-eq in 2030; without a strengthening of policies, emissions are projected
    to rise, leading to a median global warming of 2.2°C to 3.5°C by 2100 .  Projected
    cumulative future CO2 emissions over the lifetime of existing fossil fuel infrastructure
    without additional abatement exceed the total cumulative net CO2 emissions in
    pathways that limit warming to 1.5°C with no or limited overshoot. They are approximately
    equal to total cumulative net CO2 emissions in pathways that limit warming to
    2°C with a likelihood of 83% 96. Limiting warming to 2°C or lower will result
    in stranded assets. About 80% of coal, 50% of gas, and 30% of oil reserves cannot
    be burned and emitted if warming is limited to 2°C. Significantly more reserves
    are expected to remain unburned if warming is limited to 1.5°C.  Many countries
    have signalled an intention to achieve net zero GHG or net zero CO 2 emissions
    by around mid-century . More than 100 countries have either adopted, announced
    or are discussing net zero GHG or net zero CO 2 emissions commitments, covering
    more than two-thirds of global GHG emissions. A growing number of cities are setting
    climate targets, including net zero GHG targets. Many companies and institutions
    have also announced net zero emissions targets in recent years. The various net
    zero emission pledges differ across countries in terms of scope and specificity,
    and limited policies are to date in place to deliver on them.  All mitigation
    strategies face implementation challenges, including technology risks, scaling,
    and costs. Almost all mitigation options also face institutional barriers that
    need to be addressed to enable their application at scale . Current development
    pathways may create behavioural, spatial, economic and social barriers to accelerated
    mitigation at all scales. Choices made by policymakers, citizens, the private
    sector and other stakeholders influence societies’ development pathways. Structural
    factors of national circumstances and capabilities  affect the breadth and depth
    of climate governance. The extent to which civil society actors, political actors,
    businesses, youth, labour, media, Indigenous Peoples, and local communities are
    engaged influences political support for climate change mitigation and eventual
    policy outcomes.  The adoption of low-emission technologies lags in most developing
    countries, particularly least developed ones, due in part to weaker enabling conditions,
    including limited finance, technology development and transfer, and capacity .
    In many countries, especially those with limited institutional capacity, several
    adverse side-effects have been observed as a result of diffusion of low-emission
    technology, e.g., low-value employment, and dependency on foreign knowledge and
    suppliers. Low-emission innovation along with strengthened enabling conditions
    can reinforce development benefits, which can, in turn, create feedbacks towards
    greater public support for policy. Persistent and region-specific barriers also
    continue to hamper the economic and political feasibility of deploying AFOLU mitigation
    options. Barriers to implementation of AFOLU mitigation include insufficient institutional
    and financial support, uncertainty over long-term additionality and trade-offs,
    weak governance, insecure land ownership, low incomes and the lack of access to
    alternative sources of income, and the risk of reversal .
  - Long-term Climate Change  The uncertainty range on assessed future changes in
    global surface temperature is narrower than in the AR5. For the first time in
    an IPCC assessment cycle, multi-model projections of global surface temperature,
    ocean warming and sea level are constrained using observations and the assessed
    climate sensitivity. The likely range of equilibrium climate sensitivity has been
    narrowed to 2.5°C to 4.0°C based on multiple lines of evidence , including improved
    understanding of cloud feedbacks. For related emissions scenarios, this leads
    to narrower uncertainty ranges for long-term projected global temperature change
    than in AR5.  Future warming depends on future GHG emissions, with cumulative
    net CO 2 dominating. The assessed best estimates and very likely ranges of warming
    for 2081-2100 with respect to 1850–1900 vary from 1.4 [1.0 to 1.8]°C in the very
    low GHG emissions scenario to 2.7 [2.1 to 3.5]°C in the intermediate GHG emissions
    scenario and 4.4 [3.3 to 5.7]°C in the very high GHG emissions scenario 113 .  Modelled
    pathways consistent with the continuation of policies implemented by the end of
    2020 lead to global warming of 3.2 [2.2 to 3.5]°C by 2100 . Pathways of >4°C by
    2100 would imply a reversal of current technology and/or mitigation policy trends
    . However, such warming could occur in emissions pathways consistent with policies
    implemented by the end of 2020 if climate sensitivity or carbon cycle feedbacks
    are higher than the best estimate.  Global warming will continue to increase in
    the near term in nearly all considered scenarios and modelled pathways. Deep,
    rapid, and sustained GHG emissions reductions, reaching net zero CO2 emissions
    and including strong emissions reductions of other GHGs, in particular CH4, are
    necessary to limit warming to 1.5°C or less than 2°C by the end of century . The
    best estimate of reaching 1.5°C of global warming lies in the first half of the
    2030s in most of the considered scenarios and modelled pathways 114. In the very
    low GHG emissions scenario, CO 2 emissions reach net zero around 2050 and the
    best-estimate end-of-century warming is 1.4°C, after a temporary overshoot of
    no more than 0.1°C above 1.5°C global warming. Global warming of 2°C will be exceeded
    during the 21st century unless deep reductions in CO 2 and other GHG emissions
    occur in the coming decades. Deep, rapid, and sustained reductions in GHG emissions
    would lead to improvements in air quality within a few years, to reductions in
    trends of global surface temperature discernible after around 20 years, and over
    longer time periods for many other climate impact-drivers 115 . Targeted reductions
    of air pollutant emissions lead to more rapid improvements in air quality compared
    to reductions in GHG emissions only, but in the long term, further improvements
    are projected in scenarios that combine efforts to reduce air pollutants as well
    as GHG emissions 116 .   Changes in short-lived climate forcers resulting from
    the five considered scenarios lead to an additional net global warming in the
    near and long term. Simultaneous stringent climate change mitigation and air pollution
    control olicies limit this additional warming and lead to strong benefits for
    air quality. In high and very high GHG emissions scenarios, combined changes in
    SLCF emissions, such as CH 4, aerosol and ozone precursors, lead to a net global
    warming by 2100 of likely 0.4°C to 0.9°C relative to 2019. This is due to projected
    increases in atmospheric concentration of CH4, tropospheric ozone, hydrofluorocarbons
    and, when strong air pollution control is considered, reductions of cooling aerosols.
    In low and very low GHG emissions scenarios, air pollution control policies, reductions
    in CH 4 and other ozone precursors lead to a net cooling, whereas reductions in
    anthropogenic cooling aerosols lead to a net warming. Altogether, this causes
    a likely net warming of 0.0°C to 0.3°C due to SLCF changes in 2100 relative to
    2019 and strong reductions in global surface ozone and particulate matter .  Continued
    GHG emissions will further affect all major climate system components, and many
    changes will be irreversible on centennial to millennial time scales. Many changes
    in the climate system become larger in direct relation to increasing global warming.
    With every additional increment of global warming, changes in extremes continue
    to become larger. Additional warming will lead to more frequent and intense marine
    heatwaves and is projected to further amplify permafrost thawing and loss of seasonal
    snow cover, glaciers, land ice and Arctic sea ice. Continued global warming is
    projected to further intensify the global water cycle, including its variability,
    global monsoon precipitation , and very wet and very dry weather and climate events
    and seasons. The portion of global land experiencing detectable changes in seasonal
    mean precipitation is projected to increase with more variable precipitation and
    surface water flows over most land regions within seasons and from year to year
    . Many changes due to past and future GHG emissions are irreversible on centennial
    to millennial time scales, especially in the ocean, ice sheets and global sea
    level. Ocean acidification , ocean deoxygenation and global mean sea level will
    continue to increase in the 21st century, at rates dependent on future emissions.  With
    further global warming, every region is projected to increasingly experience concurrent
    and multiple changes in climatic impact-drivers. Increases in hot and decreases
    in cold climatic impact-drivers, such as temperature extremes, are projected in
    all regions. At 1.5°C global warming, heavy precipitation and flooding events
    are projected to intensify and become more frequent in most regions in Africa,
    Asia , North America and Europe . At 2°C or above, these changes expand to more
    regions and/or become more significant, and more frequent and/or severe agricultural
    and ecological droughts are projected in Europe, Africa, Australasia and North,
    Central and South America . Other projected regional changes include intensification
    of tropical cyclones and/or extratropical storms , and increases in aridity and
    fire weather . Compound heatwaves and droughts become likely more frequent, including
    concurrently at multiple locations.
  A.4.5:
  - Mitigation Actions to Date  There has been a consistent expansion of policies
    and laws addressing mitigation since AR5. Climate governance supports mitigation
    by providing frameworks through which diverse actors interact, and a basis for
    policy development and implementation. Many regulatory and economic instruments
    have already been deployed successfully. By 2020, laws primarily focussed on reducing
    GHG emissions existed in 56 countries covering 53% of global emissions. The application
    of diverse policy instruments for mitigation at the national and sub-national
    levels has grown consistently across a range of sectors. Policy coverage is uneven
    across sectors and remains limited for emissions from agriculture, and from industrial
    materials and feedstocks.  Practical experience has informed economic instrument
    design and helped to improve predictability, environmental effectiveness, economic
    efficiency, alignment with distributional goals, and social acceptance. Low-emission
    technological innovation is strengthened through the combination of technology-push
    policies, together with policies that create incentives for behaviour change and
    market opportunities. Comprehensive and consistent policy packages have been found
    to be more effective than single policies. Combining mitigation with policies
    to shift development pathways, policies that induce lifestyle or behaviour changes,
    for example, measures promoting walkable urban areas combined with electrification
    and renewable energy can create health co-benefits from cleaner air and enhanced
    active mobility . Climate governance enables mitigation by providing an overall
    direction, setting targets, mainstreaming climate action across policy domains
    and levels, based on national circumstances and in the context of international
    cooperation. Effective governance enhances regulatory certainty, creating specialised
    organisations and creating the context to mobilise finance. These functions can
    be promoted by climate-relevant laws, which are growing in number, or climate
    strategies, among others, based on national and sub-national context. Effective
    and equitable climate governance builds on engagement with civil society actors,
    political actors, businesses, youth, labour, media, Indigenous Peoples and local
    communities.  The unit costs of several low-emission technologies, including solar,
    wind and lithium-ion batteries, have fallen consistently since 2010. Design and
    process innovations in combination with the use of digital technologies have led
    to near-commercial availability of many low or zero emissions options in buildings,
    transport and industry. From 2010-2019, there have been sustained decreases in
    the unit costs of solar energy , wind energy, and lithium-ion batteries, and large
    increases in their deployment, e.g., >10× for solar and >100× for electric vehicles,
    albeit varying widely across regions. Electricity from PV and wind is now cheaper
    than electricity from fossil sources in many regions, electric vehicles are increasingly
    competitive with internal combustion engines, and large-scale battery storage
    on electricity grids is increasingly viable. In comparison to modular small-unit
    size technologies, the empirical record shows that multiple large-scale mitigation
    technologies, with fewer opportunities for learning, have seen minimal cost reductions
    and their adoption has grown slowly. Maintaining emission-intensive systems may,
    in some regions and sectors, be more expensive than transitioning to low emission
    systems.  For almost all basic materials – primary metals, building materials
    and chemicals – many low- to zero-GHG intensity production processes are at the
    pilot to near-commercial and in some cases commercial stage but they are not yet
    established industrial practice. Integrated design in construction and retrofit
    of buildings has led to increasing examples of zero energy or zero carbon buildings.
    Technological innovation made possible the widespread adoption of LED lighting.
    Digital technologies including sensors, the internet of things, robotics, and
    artificial intelligence can improve energy management in all sectors; they can
    increase energy efficiency, and promote the adoption of many low-emission technologies,
    including decentralised renewable energy, while creating economic opportunities.
    However, some of these climate change mitigation gains can be reduced or counterbalanced
    by growth in demand for goods and services due to the use of digital devices.
    Several mitigation options, notably solar energy, wind energy, electrification
    of urban systems, urban green infrastructure, energy efficiency, demand side management,
    improved forest- and crop/grassland management, and reduced food waste and loss,
    are technically viable, are becoming increasingly cost effective and are generally
    supported by the public, and this enables expanded deployment in many regions.  The
    magnitude of global climate finance flows has increased and financing channels
    have broadened. Annual tracked total financial flows for climate mitigation and
    adaptation increased by up to 60% between 2013/14 and 2019/20, but average growth
    has slowed since 2018 and most climate finance stays within national borders.
    Markets for green bonds, environmental, social and governance and sustainable
    finance products have expanded significantly since AR5 . Investors, central banks,
    and financial regulators are driving increased awareness of climate risk to support
    climate policy development and implementation. Accelerated international financial
    cooperation is a critical enabler of low-GHG and just transitions.  Economic instruments
    have been effective in reducing emissions, complemented by regulatory instruments
    mainly at the national and also sub-national and regional level. By 2020, over
    20% of global GHG emissions were covered by carbon taxes or emissions trading
    systems, although coverage and prices have been insufficient to achieve deep reductions.
    Equity and distributional impacts of carbon pricing instruments can be addressed
    by using revenue from carbon taxes or emissions trading to support low-income
    households, among other approaches. The mix of policy instruments which reduced
    costs and stimulated adoption of solar energy, wind energy and lithium-ion batteries
    includes public R&D, funding for demonstration and pilot projects, and demand-pull
    instruments such as deployment subsidies to attain scale .  Mitigation actions,
    supported by policies, have contributed to a decrease in global energy and carbon
    intensity between 2010 and 2019, with a growing number of countries achieving
    absolute GHG emission reductions for more than a decade . While global net GHG
    emissions have increased since 2010, global energy intensity decreased by 2% yr
    –1 between 2010 and 2019. Global carbon intensity also decreased by 0.3% yr –1
    , mainly due to fuel switching from coal to gas, reduced expansion of coal capacity,
    and increased use of renewables, and with large regional variations over the same
    period. In many countries, policies have enhanced energy efficiency, reduced rates
    of deforestation and accelerated technology deployment, leading to avoided and
    in some cases reduced or removed emissions. At least 18 countries have sustained
    production-based CO2 and GHG and consumption-based CO2 absolute emission reductions
    for longer than 10 years since 2005 through energy supply decarbonization, energy
    efficiency gains, and energy demand reduction, which resulted from both policies
    and changes in economic structure. Some countries have reduced production-based
    GHG emissions by a third or more since peaking, and some have achieved reduction
    rates of around 4% yr–1 for several years consecutively. Multiple lines of evidence
    suggest that mitigation policies have led to avoided global emissions of several
    GtCO 2-eq yr–1. At least 1.8 GtCO2-eq yr–1 of avoided emissions can be accounted
    for by aggregating separate estimates for the effects of economic and regulatory
    instruments. Growing numbers of laws and executive orders have impacted global
    emissions and are estimated to have resulted in 5.9 GtCO2 -eq yr–1 of avoided
    emissions in 2016. These reductions have only partly offset global emissions growth.
  - The Gap Between Mitigation Policies, Pledges and  Pathways that Limit Warming
    to 1.5°C or Below 2°C Global GHG emissions in 2030 associated with the implementation
    of NDCs announced prior to COP2691 would make it likely that warming will exceed
    1.5°C during the 21st century and would make it harder to limit warming below
    2°C – if no additional commitments are made or actions taken. A substantial ‘emissions
    gap’ exists as global GHG emissions in 2030 associated with the implementation
    of NDCs announced prior to COP26 would be similar to or only slightly below 2019
    emission levels and higher than those associated with modelled mitigation pathways
    that limit warming to 1.5°C with no or limited overshoot or to 2°C, assuming immediate
    action, which implies deep, rapid, and sustained global GHG emission reductions
    this decade  . 92 The magnitude of the emissions gap depends on the global warming
    level considered and whether only unconditional or also conditional elements of
    NDCs 93 are considered . Modelled pathways that are consistent with NDCs announced
    prior to COP26 until 2030 and assume no increase in ambition thereafter have higher
    emissions, leading to a median global warming of 2.8 [2.1 to 3.4]°C by 2100 .
    If the ‘emission gap’ is not reduced, global GHG emissions in 2030 consistent
    with NDCs announced prior to COP26 make it likely that warming will exceed 1.5°C
    during the 21st century, while limiting warming to 2°C would imply an unprecedented
    acceleration of mitigation efforts during 2030–2050 .  Policies implemented by
    the end of 2020 are projected to result in higher global GHG emissions in 2030
    than those implied by NDCs, indicating an ‘implementation gap 94 ’ . Projected
    global emissions implied by policies implemented by the end of 2020 are 57 GtCO2
    -eq in 2030. This points to an implementation gap compared with the NDCs of 4
    to 7 GtCO 2-eq in 2030; without a strengthening of policies, emissions are projected
    to rise, leading to a median global warming of 2.2°C to 3.5°C by 2100 .  Projected
    cumulative future CO2 emissions over the lifetime of existing fossil fuel infrastructure
    without additional abatement exceed the total cumulative net CO2 emissions in
    pathways that limit warming to 1.5°C with no or limited overshoot. They are approximately
    equal to total cumulative net CO2 emissions in pathways that limit warming to
    2°C with a likelihood of 83% 96. Limiting warming to 2°C or lower will result
    in stranded assets. About 80% of coal, 50% of gas, and 30% of oil reserves cannot
    be burned and emitted if warming is limited to 2°C. Significantly more reserves
    are expected to remain unburned if warming is limited to 1.5°C.  Many countries
    have signalled an intention to achieve net zero GHG or net zero CO 2 emissions
    by around mid-century . More than 100 countries have either adopted, announced
    or are discussing net zero GHG or net zero CO 2 emissions commitments, covering
    more than two-thirds of global GHG emissions. A growing number of cities are setting
    climate targets, including net zero GHG targets. Many companies and institutions
    have also announced net zero emissions targets in recent years. The various net
    zero emission pledges differ across countries in terms of scope and specificity,
    and limited policies are to date in place to deliver on them.  All mitigation
    strategies face implementation challenges, including technology risks, scaling,
    and costs. Almost all mitigation options also face institutional barriers that
    need to be addressed to enable their application at scale . Current development
    pathways may create behavioural, spatial, economic and social barriers to accelerated
    mitigation at all scales. Choices made by policymakers, citizens, the private
    sector and other stakeholders influence societies’ development pathways. Structural
    factors of national circumstances and capabilities  affect the breadth and depth
    of climate governance. The extent to which civil society actors, political actors,
    businesses, youth, labour, media, Indigenous Peoples, and local communities are
    engaged influences political support for climate change mitigation and eventual
    policy outcomes.  The adoption of low-emission technologies lags in most developing
    countries, particularly least developed ones, due in part to weaker enabling conditions,
    including limited finance, technology development and transfer, and capacity .
    In many countries, especially those with limited institutional capacity, several
    adverse side-effects have been observed as a result of diffusion of low-emission
    technology, e.g., low-value employment, and dependency on foreign knowledge and
    suppliers. Low-emission innovation along with strengthened enabling conditions
    can reinforce development benefits, which can, in turn, create feedbacks towards
    greater public support for policy. Persistent and region-specific barriers also
    continue to hamper the economic and political feasibility of deploying AFOLU mitigation
    options. Barriers to implementation of AFOLU mitigation include insufficient institutional
    and financial support, uncertainty over long-term additionality and trade-offs,
    weak governance, insecure land ownership, low incomes and the lack of access to
    alternative sources of income, and the risk of reversal .
  - 'Lack of Finance as a Barrier to Climate Action  Insufficient financing, and a
    lack of political frameworks and incentives for finance, are key causes of the
    implementation gaps for both mitigation and adaptation. Financial flows remained
    heavily focused on mitigation, are uneven, and have developed heterogeneously
    across regions and sectors. In 2018, public and publicly mobilised private climate
    finance flows from developed to developing countries were below the collective
    goal under the UNFCCC and Paris Agreement to mobilise USD 100 billion per year
    by 2020 in the context of meaningful mitigation action and transparency on implementation
    . Public and private finance flows for fossil fuels are still greater than those
    for climate adaptation and mitigation . The overwhelming majority of tracked climate
    finance is directed towards mitigation. Nevertheless, average annual modelled
    investment requirements for 2020 to 2030 in scenarios that limit warming to 2°C
    or 1.5°C are a factor of three to six greater than current levels, and total mitigation
    investments would need to increase across all sectors and regions. Challenges
    remain for green bonds and similar products, in particular around integrity and
    additionality, as well as the limited applicability of these markets to many developing
    countries.  Current global financial flows for adaptation including from public
    and private finance sources, are insufficient for and constrain implementation
    of adaptation options, especially in developing countries. There are widening
    disparities between the estimated costs of adaptation and the documented finance
    allocated to adaptation. Adaptation finance needs are estimated to be higher than
    those assessed in AR5, and the enhanced mobilisation of and access to financial
    resources are essential for implementation of adaptation and to reduce adaptation
    gaps. Annual finance flows targeting adaptation for Africa, for example, are billions
    of USD less than the lowest adaptation cost estimates for near-term climate change.
    Adverse climate impacts can further reduce the availability of financial resources
    by causing losses and damages and impeding national economic growth, thereby further
    increasing financial constraints for adaptation particularly for developing countries
    and LDCs.  Without effective mitigation and adaptation, losses and damages will
    continue to disproportionately affect the poorest and most vulnerable populations.
    Accelerated financial support for developing countries from developed countries
    and other sources is a critical enabler to enhance mitigation action . Many developing
    countries lack comprehensive data at the scale needed and lack adequate financial
    resources needed for adaptation for reducing associated economic and non-economic
    losses and damages.  There are barriers to redirecting capital towards climate
    action both within and outside the global financial sector. These barriers include:
    the inadequate assessment of climate-related risks and investment opportunities,
    regional mismatch between available capital and investment needs, home bias factors,
    country indebtedness levels, economic vulnerability, and limited institutional
    capacities. Challenges from outside the financial sector include: limited local
    capital markets; unattractive risk-return profiles, in particular due to missing
    or weak regulatory environments that are inconsistent with ambition levels; limited
    institutional capacity to ensure safeguards; standardisation, aggregation, scalability
    and replicability of investment opportunities and financing models; and, a pipeline
    ready for commercial investments.'
  B.1.1:
  - Long-term Climate Change  The uncertainty range on assessed future changes in
    global surface temperature is narrower than in the AR5. For the first time in
    an IPCC assessment cycle, multi-model projections of global surface temperature,
    ocean warming and sea level are constrained using observations and the assessed
    climate sensitivity. The likely range of equilibrium climate sensitivity has been
    narrowed to 2.5°C to 4.0°C based on multiple lines of evidence , including improved
    understanding of cloud feedbacks. For related emissions scenarios, this leads
    to narrower uncertainty ranges for long-term projected global temperature change
    than in AR5.  Future warming depends on future GHG emissions, with cumulative
    net CO 2 dominating. The assessed best estimates and very likely ranges of warming
    for 2081-2100 with respect to 1850–1900 vary from 1.4 [1.0 to 1.8]°C in the very
    low GHG emissions scenario to 2.7 [2.1 to 3.5]°C in the intermediate GHG emissions
    scenario and 4.4 [3.3 to 5.7]°C in the very high GHG emissions scenario 113 .  Modelled
    pathways consistent with the continuation of policies implemented by the end of
    2020 lead to global warming of 3.2 [2.2 to 3.5]°C by 2100 . Pathways of >4°C by
    2100 would imply a reversal of current technology and/or mitigation policy trends
    . However, such warming could occur in emissions pathways consistent with policies
    implemented by the end of 2020 if climate sensitivity or carbon cycle feedbacks
    are higher than the best estimate.  Global warming will continue to increase in
    the near term in nearly all considered scenarios and modelled pathways. Deep,
    rapid, and sustained GHG emissions reductions, reaching net zero CO2 emissions
    and including strong emissions reductions of other GHGs, in particular CH4, are
    necessary to limit warming to 1.5°C or less than 2°C by the end of century . The
    best estimate of reaching 1.5°C of global warming lies in the first half of the
    2030s in most of the considered scenarios and modelled pathways 114. In the very
    low GHG emissions scenario, CO 2 emissions reach net zero around 2050 and the
    best-estimate end-of-century warming is 1.4°C, after a temporary overshoot of
    no more than 0.1°C above 1.5°C global warming. Global warming of 2°C will be exceeded
    during the 21st century unless deep reductions in CO 2 and other GHG emissions
    occur in the coming decades. Deep, rapid, and sustained reductions in GHG emissions
    would lead to improvements in air quality within a few years, to reductions in
    trends of global surface temperature discernible after around 20 years, and over
    longer time periods for many other climate impact-drivers 115 . Targeted reductions
    of air pollutant emissions lead to more rapid improvements in air quality compared
    to reductions in GHG emissions only, but in the long term, further improvements
    are projected in scenarios that combine efforts to reduce air pollutants as well
    as GHG emissions 116 .   Changes in short-lived climate forcers resulting from
    the five considered scenarios lead to an additional net global warming in the
    near and long term. Simultaneous stringent climate change mitigation and air pollution
    control olicies limit this additional warming and lead to strong benefits for
    air quality. In high and very high GHG emissions scenarios, combined changes in
    SLCF emissions, such as CH 4, aerosol and ozone precursors, lead to a net global
    warming by 2100 of likely 0.4°C to 0.9°C relative to 2019. This is due to projected
    increases in atmospheric concentration of CH4, tropospheric ozone, hydrofluorocarbons
    and, when strong air pollution control is considered, reductions of cooling aerosols.
    In low and very low GHG emissions scenarios, air pollution control policies, reductions
    in CH 4 and other ozone precursors lead to a net cooling, whereas reductions in
    anthropogenic cooling aerosols lead to a net warming. Altogether, this causes
    a likely net warming of 0.0°C to 0.3°C due to SLCF changes in 2100 relative to
    2019 and strong reductions in global surface ozone and particulate matter .  Continued
    GHG emissions will further affect all major climate system components, and many
    changes will be irreversible on centennial to millennial time scales. Many changes
    in the climate system become larger in direct relation to increasing global warming.
    With every additional increment of global warming, changes in extremes continue
    to become larger. Additional warming will lead to more frequent and intense marine
    heatwaves and is projected to further amplify permafrost thawing and loss of seasonal
    snow cover, glaciers, land ice and Arctic sea ice. Continued global warming is
    projected to further intensify the global water cycle, including its variability,
    global monsoon precipitation , and very wet and very dry weather and climate events
    and seasons. The portion of global land experiencing detectable changes in seasonal
    mean precipitation is projected to increase with more variable precipitation and
    surface water flows over most land regions within seasons and from year to year
    . Many changes due to past and future GHG emissions are irreversible on centennial
    to millennial time scales, especially in the ocean, ice sheets and global sea
    level. Ocean acidification , ocean deoxygenation and global mean sea level will
    continue to increase in the 21st century, at rates dependent on future emissions.  With
    further global warming, every region is projected to increasingly experience concurrent
    and multiple changes in climatic impact-drivers. Increases in hot and decreases
    in cold climatic impact-drivers, such as temperature extremes, are projected in
    all regions. At 1.5°C global warming, heavy precipitation and flooding events
    are projected to intensify and become more frequent in most regions in Africa,
    Asia , North America and Europe . At 2°C or above, these changes expand to more
    regions and/or become more significant, and more frequent and/or severe agricultural
    and ecological droughts are projected in Europe, Africa, Australasia and North,
    Central and South America . Other projected regional changes include intensification
    of tropical cyclones and/or extratropical storms , and increases in aridity and
    fire weather . Compound heatwaves and droughts become likely more frequent, including
    concurrently at multiple locations.
  - 'Overshoot Pathways: Increased Risks and Other  Implications Exceeding a specific
    remaining carbon budget results in higher global warming. Achieving and sustaining
    net negative global CO 2 emissions could reverse the resulting temperature exceedance.
    Continued reductions in emissions of short-lived climate forcers, particularly
    methane, after peak temperature has been reached, would also further reduce warming.
    Only a small number of the most ambitious global modelled pathways limit global
    warming to 1.5°C without overshoot.  Overshoot of a warming level results in more
    adverse impacts, some irreversible, and additional risks for human and natural
    systems compared to staying below that warming level, with risks growing with
    the magnitude and duration of overshoot. Compared to pathways without overshoot,
    societies and ecosystems would be exposed to greater and more widespread changes
    in climatic impact-drivers, such as extreme heat and extreme precipitation, with
    increasing risks to infrastructure, low-lying coastal settlements, and associated
    livelihoods. Overshooting 1.5°C will result in irreversible adverse impacts on
    certain ecosystems with low resilience, such as polar, mountain, and coastal ecosystems,
    impacted by ice-sheet melt, glacier melt, or by accelerating and higher committed
    sea level rise. Overshoot increases the risks of severe impacts, such as increased
    wildfires, mass mortality of trees, drying of peatlands, thawing of permafrost
    and weakening natural land carbon sinks; such impacts could increase releases
    of GHGs making temperature reversal more challenging.  The larger the overshoot,
    the more net negative CO2 emissions needed to return to a given warming level.
    Reducing global temperature by removing CO 2 would require net negative emissions
    of 220 GtCO 2 for every tenth of a degree. Modelled pathways that limit warming
    to 1.5°C with no or limited overshoot reach median values of cumulative net negative
    emissions of 220 GtCO2 by 2100, pathways that return warming to 1.5°C after high
    overshoot reach median values of 360 GtCO2. 137 More rapid reduction in CO 2 and
    non-CO2 emissions, particularly methane, limits peak warming levels and reduces
    the requirement for net negative CO2 emissions and CDR, thereby reducing feasibility
    and sustainability concerns, and social and environmental risks .'
  - 'Near-Term Risks  Many changes in the climate system, including extreme events,
    will become larger in the near term with increasing global warming. Multiple climatic
    and non-climatic risks will interact, resulting in increased compounding and cascading
    impacts becoming more difficult to manage. Losses and damages will increase with
    increasing global warming, while strongly concentrated among the poorest vulnerable
    populations. Continuing with current unsustainable development patterns would
    increase exposure and vulnerability of ecosystems and people to climate hazards.
    Global warming will continue to increase in the near term mainly due to increased
    cumulative CO 2 emissions in nearly all considered scenarios and pathways. In
    the near term, every region in the world is projected to face further increases
    in climate hazards , increasing multiple risks to ecosystems and humans. In the
    near term, natural variability will modulate human-caused changes, either attenuating
    or amplifying projected changes, especially at regional scales, with little effect
    on centennial global warming. Those modulations are important to consider in adaptation
    planning. Global surface temperature in any single year can vary above or below
    the long-term human-induced trend, due to natural variability. By 2030, global
    surface temperature in any individual year could exceed 1.5°C relative to 1850–1900
    with a probability between 40% and 60%, across the five scenarios assessed in
    WGI. The occurrence of individual years with global surface temperature change
    above a certain level does not imply that this global warming level has been reached.
    If a large explosive volcanic eruption were to occur in the near term 150, it
    would temporarily and partially mask human-caused climate change by reducing global
    surface temperature and precipitation, especially over land, for one to three
    years.  The level of risk for humans and ecosystems will depend on near-term trends
    in vulnerability, exposure, level of socio-economic development and adaptation.
    In the near term, many climate-associated risks to natural and human systems depend
    more strongly on changes in these systems’ vulnerability and exposure than on
    differences in climate hazards between emissions scenarios . Future exposure to
    climatic hazards is increasing globally due to socio-economic development trends
    including growing inequality, and when urbanisation or migration increase exposure
    . Urbanisation increases hot extremes  and precipitation runoff intensity. Increasing
    urbanisation in low-lying and coastal zones will be a major driver of increasing
    exposure to extreme riverflow events and sea level rise hazards, increasing risks.
    Vulnerability will also rise rapidly in low-lying Small Island Developing States
    and atolls in the context of sea level rise . Human vulnerability will concentrate
    in informal settlements and rapidly growing smaller settlements; and vulnerability
    in rural areas will be heightened by reduced habitability and high reliance on
    climate-sensitive livelihoods. Human and ecosystem vulnerability are interdependent.
    Vulnerability to climate change for ecosystems will be strongly influenced by
    past, present, and future patterns of human development, including from unsustainable
    consumption and production, increasing demographic pressures, and persistent unsustainable
    use and management of land, ocean, and water. Several near-term risks can be moderated
    with adaptation.  Principal hazards and associated risks expected in the near
    term are: • Increased intensity and frequency of hot extremes and dangerous heat-humidity
    conditions, with increased human mortality, morbidity, and labour productivity
    loss.  • Increasing frequency of marine heatwaves will increase risks of biodiversity
    loss in the oceans, including from mass mortality events.  • Near-term risks for
    biodiversity loss are moderate to high in forest ecosystems and kelp and seagrass
    ecosystems and are high to very high in Arctic sea-ice and terrestrial ecosystems
    and warm-water coral reefs.  • More intense and frequent extreme rainfall and
    associated flooding in many regions including coastal and other low-lying cities
    , and increased proportion of and peak wind speeds of intense tropical cyclones.  •
    High risks from dryland water scarcity, wildfire damage, and permafrost degradation.  •
    Continued sea level rise and increased frequency and magnitude of extreme sea
    level events encroaching on coastal human settlements and damaging coastal infrastructure
    , committing low-lying coastal ecosystems to submergence and loss, expanding land
    salinization, with cascading to risks to livelihoods, health, well-being, cultural
    values, food and water security.  • Climate change will significantly increase
    ill health and premature deaths from the near to long term. Further warming will
    increase climate-sensitive food-borne, water-borne, and vector-borne disease risks,
    and mental health challenges including anxiety and stress.  Cryosphere-related
    changes in floods, landslides, and water availability have the potential to lead
    to severe consequences for people, infrastructure and the economy in most mountain
    regions .  • The projected increase in frequency and intensity of heavy precipitation
    will increase rain-generated local flooding.  Multiple climate change risks will
    increasingly compound and cascade in the near term. Many regions are projected
    to experience an increase in the probability of compound events with higher global
    warming including concurrent heatwaves and drought. Risks to health and food production
    will be made more severe from the interaction of sudden food production losses
    from heat and drought, exacerbated by heatinduced labour productivity losses.
    These interacting impacts will increase food prices, reduce household incomes,
    and lead to health risks of malnutrition and climate-related mortality with no
    or low levels of adaptation, especially in tropical regions . Concurrent and cascading
    risks from climate change to food systems, human settlements, infrastructure and
    health will make these risks more severe and more difficult to manage, including
    when interacting with non-climatic risk drivers such as competition for land between
    urban expansion and food production, and pandemics . Loss of ecosystems and their
    services has cascading and long-term impacts on people globally, especially for
    Indigenous Peoples and local communities who are directly dependent on ecosystems,
    to meet basic needs. Increasing transboundary risks are projected across the food,
    energy and water sectors as impacts from weather and climate extremes propagate
    through supply-chains, markets, and natural resource flows and may interact with
    impacts from other crises such as pandemics. Risks also arise from some responses
    intended to reduce the risks of climate change, including risks from maladaptation
    and adverse side effects of some emissions reduction and carbon dioxide removal
    measures, such as afforestation of naturally unforested land or poorly implemented
    bioenergy compounding climate-related risks to biodiversity, food and water security,
    and livelihoods.  With every increment of global warming losses and damages will
    increase, become increasingly difficult to avoid and be strongly concentrated
    among the poorest vulnerable populations. Adaptation does not prevent all losses
    and damages, even with effective adaptation and before reaching soft and hard
    limits. Losses and damages will be unequally distributed across systems, regions
    and sectors and are not comprehensively addressed by current financial, governance
    and institutional arrangements, particularly in vulnerable developing countries.
    .'
  B.1.4:
  - Long-term Climate Change  The uncertainty range on assessed future changes in
    global surface temperature is narrower than in the AR5. For the first time in
    an IPCC assessment cycle, multi-model projections of global surface temperature,
    ocean warming and sea level are constrained using observations and the assessed
    climate sensitivity. The likely range of equilibrium climate sensitivity has been
    narrowed to 2.5°C to 4.0°C based on multiple lines of evidence , including improved
    understanding of cloud feedbacks. For related emissions scenarios, this leads
    to narrower uncertainty ranges for long-term projected global temperature change
    than in AR5.  Future warming depends on future GHG emissions, with cumulative
    net CO 2 dominating. The assessed best estimates and very likely ranges of warming
    for 2081-2100 with respect to 1850–1900 vary from 1.4 [1.0 to 1.8]°C in the very
    low GHG emissions scenario to 2.7 [2.1 to 3.5]°C in the intermediate GHG emissions
    scenario and 4.4 [3.3 to 5.7]°C in the very high GHG emissions scenario 113 .  Modelled
    pathways consistent with the continuation of policies implemented by the end of
    2020 lead to global warming of 3.2 [2.2 to 3.5]°C by 2100 . Pathways of >4°C by
    2100 would imply a reversal of current technology and/or mitigation policy trends
    . However, such warming could occur in emissions pathways consistent with policies
    implemented by the end of 2020 if climate sensitivity or carbon cycle feedbacks
    are higher than the best estimate.  Global warming will continue to increase in
    the near term in nearly all considered scenarios and modelled pathways. Deep,
    rapid, and sustained GHG emissions reductions, reaching net zero CO2 emissions
    and including strong emissions reductions of other GHGs, in particular CH4, are
    necessary to limit warming to 1.5°C or less than 2°C by the end of century . The
    best estimate of reaching 1.5°C of global warming lies in the first half of the
    2030s in most of the considered scenarios and modelled pathways 114. In the very
    low GHG emissions scenario, CO 2 emissions reach net zero around 2050 and the
    best-estimate end-of-century warming is 1.4°C, after a temporary overshoot of
    no more than 0.1°C above 1.5°C global warming. Global warming of 2°C will be exceeded
    during the 21st century unless deep reductions in CO 2 and other GHG emissions
    occur in the coming decades. Deep, rapid, and sustained reductions in GHG emissions
    would lead to improvements in air quality within a few years, to reductions in
    trends of global surface temperature discernible after around 20 years, and over
    longer time periods for many other climate impact-drivers 115 . Targeted reductions
    of air pollutant emissions lead to more rapid improvements in air quality compared
    to reductions in GHG emissions only, but in the long term, further improvements
    are projected in scenarios that combine efforts to reduce air pollutants as well
    as GHG emissions 116 .   Changes in short-lived climate forcers resulting from
    the five considered scenarios lead to an additional net global warming in the
    near and long term. Simultaneous stringent climate change mitigation and air pollution
    control olicies limit this additional warming and lead to strong benefits for
    air quality. In high and very high GHG emissions scenarios, combined changes in
    SLCF emissions, such as CH 4, aerosol and ozone precursors, lead to a net global
    warming by 2100 of likely 0.4°C to 0.9°C relative to 2019. This is due to projected
    increases in atmospheric concentration of CH4, tropospheric ozone, hydrofluorocarbons
    and, when strong air pollution control is considered, reductions of cooling aerosols.
    In low and very low GHG emissions scenarios, air pollution control policies, reductions
    in CH 4 and other ozone precursors lead to a net cooling, whereas reductions in
    anthropogenic cooling aerosols lead to a net warming. Altogether, this causes
    a likely net warming of 0.0°C to 0.3°C due to SLCF changes in 2100 relative to
    2019 and strong reductions in global surface ozone and particulate matter .  Continued
    GHG emissions will further affect all major climate system components, and many
    changes will be irreversible on centennial to millennial time scales. Many changes
    in the climate system become larger in direct relation to increasing global warming.
    With every additional increment of global warming, changes in extremes continue
    to become larger. Additional warming will lead to more frequent and intense marine
    heatwaves and is projected to further amplify permafrost thawing and loss of seasonal
    snow cover, glaciers, land ice and Arctic sea ice. Continued global warming is
    projected to further intensify the global water cycle, including its variability,
    global monsoon precipitation , and very wet and very dry weather and climate events
    and seasons. The portion of global land experiencing detectable changes in seasonal
    mean precipitation is projected to increase with more variable precipitation and
    surface water flows over most land regions within seasons and from year to year
    . Many changes due to past and future GHG emissions are irreversible on centennial
    to millennial time scales, especially in the ocean, ice sheets and global sea
    level. Ocean acidification , ocean deoxygenation and global mean sea level will
    continue to increase in the 21st century, at rates dependent on future emissions.  With
    further global warming, every region is projected to increasingly experience concurrent
    and multiple changes in climatic impact-drivers. Increases in hot and decreases
    in cold climatic impact-drivers, such as temperature extremes, are projected in
    all regions. At 1.5°C global warming, heavy precipitation and flooding events
    are projected to intensify and become more frequent in most regions in Africa,
    Asia , North America and Europe . At 2°C or above, these changes expand to more
    regions and/or become more significant, and more frequent and/or severe agricultural
    and ecological droughts are projected in Europe, Africa, Australasia and North,
    Central and South America . Other projected regional changes include intensification
    of tropical cyclones and/or extratropical storms , and increases in aridity and
    fire weather . Compound heatwaves and droughts become likely more frequent, including
    concurrently at multiple locations.
  - 'The Likelihood and Risks of Abrupt and Irreversible  Change The likelihood of
    abrupt and irreversible changes and their impacts increase with higher global
    warming levels. As warming levels increase, so do the risks of species extinction
    or irreversible loss of biodiversity in ecosystems such as forests , coral reefs
    and in Arctic regions . Risks associated with large-scale singular events or tipping
    points, such as ice sheet instability or ecosystem loss from tropical forests,
    transition to high risk between 1.5°C to 2.5°C  and to very high risk between
    2.5°C to 4°C. The response of biogeochemical cycles to anthropogenic perturbations
    can be abrupt at regional scales and irreversible on decadal to century time scales.
    The probability of crossing uncertain regional thresholds increases with further
    warming.  Sea level rise is unavoidable for centuries to millennia due to continuing
    deep ocean warming and ice sheet melt, and sea levels will remain elevated for
    thousands of years . Global mean sea level rise will continue in the 21st century,
    with projected regional relative sea level rise within 20% of the global mean
    along two-thirds of the global coastline . The magnitude, the rate, the timing
    of threshold exceedances, and the long-term commitment of sea level rise depend
    on emissions, with higher emissions leading to greater and faster rates of sea
    level rise. Due to relative sea level rise, extreme sea level events that occurred
    once per century in the recent past are projected to occur at least annually at
    more than half of all tide gauge locations by 2100 and risks for coastal ecosystems,
    people and infrastructure will continue to increase beyond 2100. At sustained
    warming levels between 2°C and 3°C, the Greenland and West Antarctic ice sheets
    will be lost almost completely and irreversibly over multiple millennia. The probability
    and rate of ice mass loss increase with higher global surface temperatures. Over
    the next 2000 years, global mean sea level will rise by about 2 to 3 m if warming
    is limited to 1.5°C and 2 to 6 m if limited to 2°C . Projections of multi-millennial
    global mean sea level rise are consistent with reconstructed levels during past
    warm climate periods: global mean sea level was very likely 5 to 25 m higher than
    today roughly 3 million years ago, when global temperatures were 2.5°C to 4°C
    higher than 1850–1900. Further examples of unavoidable changes in the climate
    system due to multi-decadal or longer response timescales include continued glacier
    melt  and permafrost carbon loss.  The probability of low-likelihood outcomes
    associated with potentially very large impacts increases with higher global warming
    levels. Warming substantially above the assessed very likely range for a given
    scenario cannot be ruled out, and there is high confidence this would lead to
    regional changes greater than assessed in many aspects of the climate system.
    Low-likelihood, high-impact outcomes could occur at regional scales even for global
    warming within the very likely assessed range for a given GHG emissions scenario.
    Global mean sea level rise above the likely range – approaching 2 m by 2100 and
    in excess of 15 m by 2300 under a very high GHG emissions scenario  – cannot be
    ruled out due to deep uncertainty in ice-sheet processes 123 and would have severe
    impacts on populations in low elevation coastal zones. If global warming increases,
    some compound extreme events 124 will become more frequent, with higher likelihood
    of unprecedented intensities, durations or spatial extent. The Atlantic Meridional
    Overturning Circulation is very likely to weaken over the 21st century for all
    considered scenarios, however an abrupt collapse is not expected before 2100 .
    If such a low probability event were to occur, it would very likely cause abrupt
    shifts in regional weather patterns and water cycle, such as a southward shift
    in the tropical rain belt, and large impacts on ecosystems and human activities.
    A sequence of large explosive volcanic eruptions within decades, as have occurred
    in the past, is a low-likelihood high-impact event that would lead to substantial
    cooling globally and regional climate perturbations over several decades.'
  B.1.5:
  - 'Near-Term Risks  Many changes in the climate system, including extreme events,
    will become larger in the near term with increasing global warming. Multiple climatic
    and non-climatic risks will interact, resulting in increased compounding and cascading
    impacts becoming more difficult to manage. Losses and damages will increase with
    increasing global warming, while strongly concentrated among the poorest vulnerable
    populations. Continuing with current unsustainable development patterns would
    increase exposure and vulnerability of ecosystems and people to climate hazards.
    Global warming will continue to increase in the near term mainly due to increased
    cumulative CO 2 emissions in nearly all considered scenarios and pathways. In
    the near term, every region in the world is projected to face further increases
    in climate hazards , increasing multiple risks to ecosystems and humans. In the
    near term, natural variability will modulate human-caused changes, either attenuating
    or amplifying projected changes, especially at regional scales, with little effect
    on centennial global warming. Those modulations are important to consider in adaptation
    planning. Global surface temperature in any single year can vary above or below
    the long-term human-induced trend, due to natural variability. By 2030, global
    surface temperature in any individual year could exceed 1.5°C relative to 1850–1900
    with a probability between 40% and 60%, across the five scenarios assessed in
    WGI. The occurrence of individual years with global surface temperature change
    above a certain level does not imply that this global warming level has been reached.
    If a large explosive volcanic eruption were to occur in the near term 150, it
    would temporarily and partially mask human-caused climate change by reducing global
    surface temperature and precipitation, especially over land, for one to three
    years.  The level of risk for humans and ecosystems will depend on near-term trends
    in vulnerability, exposure, level of socio-economic development and adaptation.
    In the near term, many climate-associated risks to natural and human systems depend
    more strongly on changes in these systems’ vulnerability and exposure than on
    differences in climate hazards between emissions scenarios . Future exposure to
    climatic hazards is increasing globally due to socio-economic development trends
    including growing inequality, and when urbanisation or migration increase exposure
    . Urbanisation increases hot extremes  and precipitation runoff intensity. Increasing
    urbanisation in low-lying and coastal zones will be a major driver of increasing
    exposure to extreme riverflow events and sea level rise hazards, increasing risks.
    Vulnerability will also rise rapidly in low-lying Small Island Developing States
    and atolls in the context of sea level rise . Human vulnerability will concentrate
    in informal settlements and rapidly growing smaller settlements; and vulnerability
    in rural areas will be heightened by reduced habitability and high reliance on
    climate-sensitive livelihoods. Human and ecosystem vulnerability are interdependent.
    Vulnerability to climate change for ecosystems will be strongly influenced by
    past, present, and future patterns of human development, including from unsustainable
    consumption and production, increasing demographic pressures, and persistent unsustainable
    use and management of land, ocean, and water. Several near-term risks can be moderated
    with adaptation.  Principal hazards and associated risks expected in the near
    term are: • Increased intensity and frequency of hot extremes and dangerous heat-humidity
    conditions, with increased human mortality, morbidity, and labour productivity
    loss.  • Increasing frequency of marine heatwaves will increase risks of biodiversity
    loss in the oceans, including from mass mortality events.  • Near-term risks for
    biodiversity loss are moderate to high in forest ecosystems and kelp and seagrass
    ecosystems and are high to very high in Arctic sea-ice and terrestrial ecosystems
    and warm-water coral reefs.  • More intense and frequent extreme rainfall and
    associated flooding in many regions including coastal and other low-lying cities
    , and increased proportion of and peak wind speeds of intense tropical cyclones.  •
    High risks from dryland water scarcity, wildfire damage, and permafrost degradation.  •
    Continued sea level rise and increased frequency and magnitude of extreme sea
    level events encroaching on coastal human settlements and damaging coastal infrastructure
    , committing low-lying coastal ecosystems to submergence and loss, expanding land
    salinization, with cascading to risks to livelihoods, health, well-being, cultural
    values, food and water security.  • Climate change will significantly increase
    ill health and premature deaths from the near to long term. Further warming will
    increase climate-sensitive food-borne, water-borne, and vector-borne disease risks,
    and mental health challenges including anxiety and stress.  Cryosphere-related
    changes in floods, landslides, and water availability have the potential to lead
    to severe consequences for people, infrastructure and the economy in most mountain
    regions .  • The projected increase in frequency and intensity of heavy precipitation
    will increase rain-generated local flooding.  Multiple climate change risks will
    increasingly compound and cascade in the near term. Many regions are projected
    to experience an increase in the probability of compound events with higher global
    warming including concurrent heatwaves and drought. Risks to health and food production
    will be made more severe from the interaction of sudden food production losses
    from heat and drought, exacerbated by heatinduced labour productivity losses.
    These interacting impacts will increase food prices, reduce household incomes,
    and lead to health risks of malnutrition and climate-related mortality with no
    or low levels of adaptation, especially in tropical regions . Concurrent and cascading
    risks from climate change to food systems, human settlements, infrastructure and
    health will make these risks more severe and more difficult to manage, including
    when interacting with non-climatic risk drivers such as competition for land between
    urban expansion and food production, and pandemics . Loss of ecosystems and their
    services has cascading and long-term impacts on people globally, especially for
    Indigenous Peoples and local communities who are directly dependent on ecosystems,
    to meet basic needs. Increasing transboundary risks are projected across the food,
    energy and water sectors as impacts from weather and climate extremes propagate
    through supply-chains, markets, and natural resource flows and may interact with
    impacts from other crises such as pandemics. Risks also arise from some responses
    intended to reduce the risks of climate change, including risks from maladaptation
    and adverse side effects of some emissions reduction and carbon dioxide removal
    measures, such as afforestation of naturally unforested land or poorly implemented
    bioenergy compounding climate-related risks to biodiversity, food and water security,
    and livelihoods.  With every increment of global warming losses and damages will
    increase, become increasingly difficult to avoid and be strongly concentrated
    among the poorest vulnerable populations. Adaptation does not prevent all losses
    and damages, even with effective adaptation and before reaching soft and hard
    limits. Losses and damages will be unequally distributed across systems, regions
    and sectors and are not comprehensively addressed by current financial, governance
    and institutional arrangements, particularly in vulnerable developing countries.
    .'
  B.2.1:
  - 'Near-Term Risks  Many changes in the climate system, including extreme events,
    will become larger in the near term with increasing global warming. Multiple climatic
    and non-climatic risks will interact, resulting in increased compounding and cascading
    impacts becoming more difficult to manage. Losses and damages will increase with
    increasing global warming, while strongly concentrated among the poorest vulnerable
    populations. Continuing with current unsustainable development patterns would
    increase exposure and vulnerability of ecosystems and people to climate hazards.
    Global warming will continue to increase in the near term mainly due to increased
    cumulative CO 2 emissions in nearly all considered scenarios and pathways. In
    the near term, every region in the world is projected to face further increases
    in climate hazards , increasing multiple risks to ecosystems and humans. In the
    near term, natural variability will modulate human-caused changes, either attenuating
    or amplifying projected changes, especially at regional scales, with little effect
    on centennial global warming. Those modulations are important to consider in adaptation
    planning. Global surface temperature in any single year can vary above or below
    the long-term human-induced trend, due to natural variability. By 2030, global
    surface temperature in any individual year could exceed 1.5°C relative to 1850–1900
    with a probability between 40% and 60%, across the five scenarios assessed in
    WGI. The occurrence of individual years with global surface temperature change
    above a certain level does not imply that this global warming level has been reached.
    If a large explosive volcanic eruption were to occur in the near term 150, it
    would temporarily and partially mask human-caused climate change by reducing global
    surface temperature and precipitation, especially over land, for one to three
    years.  The level of risk for humans and ecosystems will depend on near-term trends
    in vulnerability, exposure, level of socio-economic development and adaptation.
    In the near term, many climate-associated risks to natural and human systems depend
    more strongly on changes in these systems’ vulnerability and exposure than on
    differences in climate hazards between emissions scenarios . Future exposure to
    climatic hazards is increasing globally due to socio-economic development trends
    including growing inequality, and when urbanisation or migration increase exposure
    . Urbanisation increases hot extremes  and precipitation runoff intensity. Increasing
    urbanisation in low-lying and coastal zones will be a major driver of increasing
    exposure to extreme riverflow events and sea level rise hazards, increasing risks.
    Vulnerability will also rise rapidly in low-lying Small Island Developing States
    and atolls in the context of sea level rise . Human vulnerability will concentrate
    in informal settlements and rapidly growing smaller settlements; and vulnerability
    in rural areas will be heightened by reduced habitability and high reliance on
    climate-sensitive livelihoods. Human and ecosystem vulnerability are interdependent.
    Vulnerability to climate change for ecosystems will be strongly influenced by
    past, present, and future patterns of human development, including from unsustainable
    consumption and production, increasing demographic pressures, and persistent unsustainable
    use and management of land, ocean, and water. Several near-term risks can be moderated
    with adaptation.  Principal hazards and associated risks expected in the near
    term are: • Increased intensity and frequency of hot extremes and dangerous heat-humidity
    conditions, with increased human mortality, morbidity, and labour productivity
    loss.  • Increasing frequency of marine heatwaves will increase risks of biodiversity
    loss in the oceans, including from mass mortality events.  • Near-term risks for
    biodiversity loss are moderate to high in forest ecosystems and kelp and seagrass
    ecosystems and are high to very high in Arctic sea-ice and terrestrial ecosystems
    and warm-water coral reefs.  • More intense and frequent extreme rainfall and
    associated flooding in many regions including coastal and other low-lying cities
    , and increased proportion of and peak wind speeds of intense tropical cyclones.  •
    High risks from dryland water scarcity, wildfire damage, and permafrost degradation.  •
    Continued sea level rise and increased frequency and magnitude of extreme sea
    level events encroaching on coastal human settlements and damaging coastal infrastructure
    , committing low-lying coastal ecosystems to submergence and loss, expanding land
    salinization, with cascading to risks to livelihoods, health, well-being, cultural
    values, food and water security.  • Climate change will significantly increase
    ill health and premature deaths from the near to long term. Further warming will
    increase climate-sensitive food-borne, water-borne, and vector-borne disease risks,
    and mental health challenges including anxiety and stress.  Cryosphere-related
    changes in floods, landslides, and water availability have the potential to lead
    to severe consequences for people, infrastructure and the economy in most mountain
    regions .  • The projected increase in frequency and intensity of heavy precipitation
    will increase rain-generated local flooding.  Multiple climate change risks will
    increasingly compound and cascade in the near term. Many regions are projected
    to experience an increase in the probability of compound events with higher global
    warming including concurrent heatwaves and drought. Risks to health and food production
    will be made more severe from the interaction of sudden food production losses
    from heat and drought, exacerbated by heatinduced labour productivity losses.
    These interacting impacts will increase food prices, reduce household incomes,
    and lead to health risks of malnutrition and climate-related mortality with no
    or low levels of adaptation, especially in tropical regions . Concurrent and cascading
    risks from climate change to food systems, human settlements, infrastructure and
    health will make these risks more severe and more difficult to manage, including
    when interacting with non-climatic risk drivers such as competition for land between
    urban expansion and food production, and pandemics . Loss of ecosystems and their
    services has cascading and long-term impacts on people globally, especially for
    Indigenous Peoples and local communities who are directly dependent on ecosystems,
    to meet basic needs. Increasing transboundary risks are projected across the food,
    energy and water sectors as impacts from weather and climate extremes propagate
    through supply-chains, markets, and natural resource flows and may interact with
    impacts from other crises such as pandemics. Risks also arise from some responses
    intended to reduce the risks of climate change, including risks from maladaptation
    and adverse side effects of some emissions reduction and carbon dioxide removal
    measures, such as afforestation of naturally unforested land or poorly implemented
    bioenergy compounding climate-related risks to biodiversity, food and water security,
    and livelihoods.  With every increment of global warming losses and damages will
    increase, become increasingly difficult to avoid and be strongly concentrated
    among the poorest vulnerable populations. Adaptation does not prevent all losses
    and damages, even with effective adaptation and before reaching soft and hard
    limits. Losses and damages will be unequally distributed across systems, regions
    and sectors and are not comprehensively addressed by current financial, governance
    and institutional arrangements, particularly in vulnerable developing countries.
    .'
  B.2.2:
  - Impacts and Related Risks  For a given level of warming, many climate-related
    risks are assessed to be higher than in AR5. Levels of risk for all Reasons for
    Concern 121 are assessed to become high to very high at lower global warming levels
    compared to what was assessed in AR5. This is based upon recent evidence of observed
    impacts, improved process understanding, and new knowledge on exposure and vulnerability
    of human and natural systems, including limits to adaptation. Depending on the
    level of global warming, the assessed long-term impacts will be up to multiple
    times higher than currently observed for 127 identified key risks, e.g., in terms
    of the number of affected people and species. Risks, including cascading risks
    and risks from overshoot, are projected to become increasingly severe with every
    increment of global warming.  Climate-related risks for natural and human systems
    are higher for global warming of 1.5°C than at present but lower than at 2°C .
    Climate-related risks to health, livelihoods, food security, water supply, human
    security, and economic growth are projected to increase with global warming of
    1.5°C. In terrestrial ecosystems, 3 to 14% of the tens of thousands of species
    assessed will likely face a very high risk of extinction at a GWL of 1.5°C. Coral
    reefs are projected to decline by a further 70–90% at 1.5°C of global warming.
    At this GWL, many low-elevation and small glaciers around the world would lose
    most of their mass or disappear within decades to centuries. Regions at disproportionately
    higher risk include Arctic ecosystems, dryland regions, small island developing
    states and Least Developed Countries .  At 2°C of global warming, overall risk
    levels associated with the unequal distribution of impacts, global aggregate impacts
    and large-scale singular events would be transitioning to high , those associated
    with extreme weather events would be transitioning to very high, and those associated
    with unique and threatened systems would be very high  . With about 2°C warming,
    climate-related changes in food availability and diet quality are estimated to
    increase nutrition-related diseases and the number of undernourished people, affecting
    tens to hundreds of millions of people, particularly among low-income households
    in low- and middle-income countries in sub-Saharan Africa, South Asia and Central
    America. For example, snowmelt water availability for irrigation is projected
    to decline in some snowmelt dependent river basins by up to 20% . Climate change
    risks to cities, settlements and key infrastructure will rise sharply in the mid
    and long term with further global warming, especially in places already exposed
    to high temperatures, along coastlines, or with high vulnerabilities .  At global
    warming of 3°C, additional risks in many sectors and regions reach high or very
    high levels, implying widespread systemic impacts, irreversible change and many
    additional adaptation limits . For example, very high extinction risk for endemic
    species in biodiversity hotspots is projected to increase at least tenfold if
    warming rises from 1.5°C to 3°C. Projected increases in direct flood damages are
    higher by 1.4 to 2 times at 2°C and 2.5 to 3.9 times at 3°C, compared to 1.5°C
    global warming without adaptation.  Global warming of 4°C and above is projected
    to lead to far-reaching impacts on natural and human systems. Beyond 4°C of warming,
    projected impacts on natural systems include local extinction of ~50% of tropical
    marine species and biome shifts across 35% of global land area. At this level
    of warming, approximately 10% of the global land area is projected to face both
    increasing high and decreasing low extreme streamflow, affecting, without additional
    adaptation, over 2.1 billion people and about 4 billion people are projected to
    experience water scarcity. At 4°C of warming, the global burned area is projected
    to increase by 50 to 70% and the fire frequency by ~30% compared to today.  Projected
    adverse impacts and related losses and damages from climate change escalate with
    every increment of global warming , but they will also strongly depend on socio-economic
    development trajectories and adaptation actions to reduce vulnerability and exposure.
    For example, development pathways with higher demand for food, animal feed, and
    water, more resource-intensive consumption and production, and limited technological
    improvements result in higher risks from water scarcity in drylands, land degradation
    and food insecurity . Changes in, for example, demography or investments in health
    systems have effect on a variety of health-related outcomes including heat-related
    morbidity and mortality.  With every increment of warming, climate change impacts
    and risks will become increasingly complex and more difficult to manage. Many
    regions are projected to experience an increase in the probability of compound
    events with higher global warming, such as concurrent heatwaves and droughts,
    compound flooding and fire weather. In addition, multiple climatic and non-climatic
    risk drivers such as biodiversity loss or violent conflict will interact, resulting
    in compounding overall risk and risks cascading across sectors and regions. Furthermore,
    risks can arise from some responses that are intended to reduce the risks of climate
    change, e.g., adverse side effects of some emission reduction and carbon dioxide
    removal measures .  Solar Radiation Modification approaches, if they were to be
    implemented, introduce a widespread range of new risks to people and ecosystems,
    which are not well understood. SRM has the potential to offset warming within
    one or two decades and ameliorate some climate hazards but would not restore climate
    to a previous state, and substantial residual or overcompensating climate change
    would occur at regional and seasonal scales. Effects of SRM would depend on the
    specific approach used 122, and a sudden and sustained termination of SRM in a
    high CO 2 emissions scenario would cause rapid climate change. SRM would not stop
    atmospheric CO 2 concentrations from increasing nor reduce resulting ocean acidification
    under continued anthropogenic emissions. Large uncertainties and knowledge gaps
    are associated with the potential of SRM approaches to reduce climate change risks.
    Lack of robust and formal SRM governance poses risks as deployment by a limited
    number of states could create international tensions.
  - 'The Likelihood and Risks of Abrupt and Irreversible  Change The likelihood of
    abrupt and irreversible changes and their impacts increase with higher global
    warming levels. As warming levels increase, so do the risks of species extinction
    or irreversible loss of biodiversity in ecosystems such as forests , coral reefs
    and in Arctic regions . Risks associated with large-scale singular events or tipping
    points, such as ice sheet instability or ecosystem loss from tropical forests,
    transition to high risk between 1.5°C to 2.5°C  and to very high risk between
    2.5°C to 4°C. The response of biogeochemical cycles to anthropogenic perturbations
    can be abrupt at regional scales and irreversible on decadal to century time scales.
    The probability of crossing uncertain regional thresholds increases with further
    warming.  Sea level rise is unavoidable for centuries to millennia due to continuing
    deep ocean warming and ice sheet melt, and sea levels will remain elevated for
    thousands of years . Global mean sea level rise will continue in the 21st century,
    with projected regional relative sea level rise within 20% of the global mean
    along two-thirds of the global coastline . The magnitude, the rate, the timing
    of threshold exceedances, and the long-term commitment of sea level rise depend
    on emissions, with higher emissions leading to greater and faster rates of sea
    level rise. Due to relative sea level rise, extreme sea level events that occurred
    once per century in the recent past are projected to occur at least annually at
    more than half of all tide gauge locations by 2100 and risks for coastal ecosystems,
    people and infrastructure will continue to increase beyond 2100. At sustained
    warming levels between 2°C and 3°C, the Greenland and West Antarctic ice sheets
    will be lost almost completely and irreversibly over multiple millennia. The probability
    and rate of ice mass loss increase with higher global surface temperatures. Over
    the next 2000 years, global mean sea level will rise by about 2 to 3 m if warming
    is limited to 1.5°C and 2 to 6 m if limited to 2°C . Projections of multi-millennial
    global mean sea level rise are consistent with reconstructed levels during past
    warm climate periods: global mean sea level was very likely 5 to 25 m higher than
    today roughly 3 million years ago, when global temperatures were 2.5°C to 4°C
    higher than 1850–1900. Further examples of unavoidable changes in the climate
    system due to multi-decadal or longer response timescales include continued glacier
    melt  and permafrost carbon loss.  The probability of low-likelihood outcomes
    associated with potentially very large impacts increases with higher global warming
    levels. Warming substantially above the assessed very likely range for a given
    scenario cannot be ruled out, and there is high confidence this would lead to
    regional changes greater than assessed in many aspects of the climate system.
    Low-likelihood, high-impact outcomes could occur at regional scales even for global
    warming within the very likely assessed range for a given GHG emissions scenario.
    Global mean sea level rise above the likely range – approaching 2 m by 2100 and
    in excess of 15 m by 2300 under a very high GHG emissions scenario  – cannot be
    ruled out due to deep uncertainty in ice-sheet processes 123 and would have severe
    impacts on populations in low elevation coastal zones. If global warming increases,
    some compound extreme events 124 will become more frequent, with higher likelihood
    of unprecedented intensities, durations or spatial extent. The Atlantic Meridional
    Overturning Circulation is very likely to weaken over the 21st century for all
    considered scenarios, however an abrupt collapse is not expected before 2100 .
    If such a low probability event were to occur, it would very likely cause abrupt
    shifts in regional weather patterns and water cycle, such as a southward shift
    in the tropical rain belt, and large impacts on ecosystems and human activities.
    A sequence of large explosive volcanic eruptions within decades, as have occurred
    in the past, is a low-likelihood high-impact event that would lead to substantial
    cooling globally and regional climate perturbations over several decades.'
  B.3.1:
  - 'The Likelihood and Risks of Abrupt and Irreversible  Change The likelihood of
    abrupt and irreversible changes and their impacts increase with higher global
    warming levels. As warming levels increase, so do the risks of species extinction
    or irreversible loss of biodiversity in ecosystems such as forests , coral reefs
    and in Arctic regions . Risks associated with large-scale singular events or tipping
    points, such as ice sheet instability or ecosystem loss from tropical forests,
    transition to high risk between 1.5°C to 2.5°C  and to very high risk between
    2.5°C to 4°C. The response of biogeochemical cycles to anthropogenic perturbations
    can be abrupt at regional scales and irreversible on decadal to century time scales.
    The probability of crossing uncertain regional thresholds increases with further
    warming.  Sea level rise is unavoidable for centuries to millennia due to continuing
    deep ocean warming and ice sheet melt, and sea levels will remain elevated for
    thousands of years . Global mean sea level rise will continue in the 21st century,
    with projected regional relative sea level rise within 20% of the global mean
    along two-thirds of the global coastline . The magnitude, the rate, the timing
    of threshold exceedances, and the long-term commitment of sea level rise depend
    on emissions, with higher emissions leading to greater and faster rates of sea
    level rise. Due to relative sea level rise, extreme sea level events that occurred
    once per century in the recent past are projected to occur at least annually at
    more than half of all tide gauge locations by 2100 and risks for coastal ecosystems,
    people and infrastructure will continue to increase beyond 2100. At sustained
    warming levels between 2°C and 3°C, the Greenland and West Antarctic ice sheets
    will be lost almost completely and irreversibly over multiple millennia. The probability
    and rate of ice mass loss increase with higher global surface temperatures. Over
    the next 2000 years, global mean sea level will rise by about 2 to 3 m if warming
    is limited to 1.5°C and 2 to 6 m if limited to 2°C . Projections of multi-millennial
    global mean sea level rise are consistent with reconstructed levels during past
    warm climate periods: global mean sea level was very likely 5 to 25 m higher than
    today roughly 3 million years ago, when global temperatures were 2.5°C to 4°C
    higher than 1850–1900. Further examples of unavoidable changes in the climate
    system due to multi-decadal or longer response timescales include continued glacier
    melt  and permafrost carbon loss.  The probability of low-likelihood outcomes
    associated with potentially very large impacts increases with higher global warming
    levels. Warming substantially above the assessed very likely range for a given
    scenario cannot be ruled out, and there is high confidence this would lead to
    regional changes greater than assessed in many aspects of the climate system.
    Low-likelihood, high-impact outcomes could occur at regional scales even for global
    warming within the very likely assessed range for a given GHG emissions scenario.
    Global mean sea level rise above the likely range – approaching 2 m by 2100 and
    in excess of 15 m by 2300 under a very high GHG emissions scenario  – cannot be
    ruled out due to deep uncertainty in ice-sheet processes 123 and would have severe
    impacts on populations in low elevation coastal zones. If global warming increases,
    some compound extreme events 124 will become more frequent, with higher likelihood
    of unprecedented intensities, durations or spatial extent. The Atlantic Meridional
    Overturning Circulation is very likely to weaken over the 21st century for all
    considered scenarios, however an abrupt collapse is not expected before 2100 .
    If such a low probability event were to occur, it would very likely cause abrupt
    shifts in regional weather patterns and water cycle, such as a southward shift
    in the tropical rain belt, and large impacts on ecosystems and human activities.
    A sequence of large explosive volcanic eruptions within decades, as have occurred
    in the past, is a low-likelihood high-impact event that would lead to substantial
    cooling globally and regional climate perturbations over several decades.'
  B.3.2:
  - Impacts and Related Risks  For a given level of warming, many climate-related
    risks are assessed to be higher than in AR5. Levels of risk for all Reasons for
    Concern 121 are assessed to become high to very high at lower global warming levels
    compared to what was assessed in AR5. This is based upon recent evidence of observed
    impacts, improved process understanding, and new knowledge on exposure and vulnerability
    of human and natural systems, including limits to adaptation. Depending on the
    level of global warming, the assessed long-term impacts will be up to multiple
    times higher than currently observed for 127 identified key risks, e.g., in terms
    of the number of affected people and species. Risks, including cascading risks
    and risks from overshoot, are projected to become increasingly severe with every
    increment of global warming.  Climate-related risks for natural and human systems
    are higher for global warming of 1.5°C than at present but lower than at 2°C .
    Climate-related risks to health, livelihoods, food security, water supply, human
    security, and economic growth are projected to increase with global warming of
    1.5°C. In terrestrial ecosystems, 3 to 14% of the tens of thousands of species
    assessed will likely face a very high risk of extinction at a GWL of 1.5°C. Coral
    reefs are projected to decline by a further 70–90% at 1.5°C of global warming.
    At this GWL, many low-elevation and small glaciers around the world would lose
    most of their mass or disappear within decades to centuries. Regions at disproportionately
    higher risk include Arctic ecosystems, dryland regions, small island developing
    states and Least Developed Countries .  At 2°C of global warming, overall risk
    levels associated with the unequal distribution of impacts, global aggregate impacts
    and large-scale singular events would be transitioning to high , those associated
    with extreme weather events would be transitioning to very high, and those associated
    with unique and threatened systems would be very high  . With about 2°C warming,
    climate-related changes in food availability and diet quality are estimated to
    increase nutrition-related diseases and the number of undernourished people, affecting
    tens to hundreds of millions of people, particularly among low-income households
    in low- and middle-income countries in sub-Saharan Africa, South Asia and Central
    America. For example, snowmelt water availability for irrigation is projected
    to decline in some snowmelt dependent river basins by up to 20% . Climate change
    risks to cities, settlements and key infrastructure will rise sharply in the mid
    and long term with further global warming, especially in places already exposed
    to high temperatures, along coastlines, or with high vulnerabilities .  At global
    warming of 3°C, additional risks in many sectors and regions reach high or very
    high levels, implying widespread systemic impacts, irreversible change and many
    additional adaptation limits . For example, very high extinction risk for endemic
    species in biodiversity hotspots is projected to increase at least tenfold if
    warming rises from 1.5°C to 3°C. Projected increases in direct flood damages are
    higher by 1.4 to 2 times at 2°C and 2.5 to 3.9 times at 3°C, compared to 1.5°C
    global warming without adaptation.  Global warming of 4°C and above is projected
    to lead to far-reaching impacts on natural and human systems. Beyond 4°C of warming,
    projected impacts on natural systems include local extinction of ~50% of tropical
    marine species and biome shifts across 35% of global land area. At this level
    of warming, approximately 10% of the global land area is projected to face both
    increasing high and decreasing low extreme streamflow, affecting, without additional
    adaptation, over 2.1 billion people and about 4 billion people are projected to
    experience water scarcity. At 4°C of warming, the global burned area is projected
    to increase by 50 to 70% and the fire frequency by ~30% compared to today.  Projected
    adverse impacts and related losses and damages from climate change escalate with
    every increment of global warming , but they will also strongly depend on socio-economic
    development trajectories and adaptation actions to reduce vulnerability and exposure.
    For example, development pathways with higher demand for food, animal feed, and
    water, more resource-intensive consumption and production, and limited technological
    improvements result in higher risks from water scarcity in drylands, land degradation
    and food insecurity . Changes in, for example, demography or investments in health
    systems have effect on a variety of health-related outcomes including heat-related
    morbidity and mortality.  With every increment of warming, climate change impacts
    and risks will become increasingly complex and more difficult to manage. Many
    regions are projected to experience an increase in the probability of compound
    events with higher global warming, such as concurrent heatwaves and droughts,
    compound flooding and fire weather. In addition, multiple climatic and non-climatic
    risk drivers such as biodiversity loss or violent conflict will interact, resulting
    in compounding overall risk and risks cascading across sectors and regions. Furthermore,
    risks can arise from some responses that are intended to reduce the risks of climate
    change, e.g., adverse side effects of some emission reduction and carbon dioxide
    removal measures .  Solar Radiation Modification approaches, if they were to be
    implemented, introduce a widespread range of new risks to people and ecosystems,
    which are not well understood. SRM has the potential to offset warming within
    one or two decades and ameliorate some climate hazards but would not restore climate
    to a previous state, and substantial residual or overcompensating climate change
    would occur at regional and seasonal scales. Effects of SRM would depend on the
    specific approach used 122, and a sudden and sustained termination of SRM in a
    high CO 2 emissions scenario would cause rapid climate change. SRM would not stop
    atmospheric CO 2 concentrations from increasing nor reduce resulting ocean acidification
    under continued anthropogenic emissions. Large uncertainties and knowledge gaps
    are associated with the potential of SRM approaches to reduce climate change risks.
    Lack of robust and formal SRM governance poses risks as deployment by a limited
    number of states could create international tensions.
  - 'The Likelihood and Risks of Abrupt and Irreversible  Change The likelihood of
    abrupt and irreversible changes and their impacts increase with higher global
    warming levels. As warming levels increase, so do the risks of species extinction
    or irreversible loss of biodiversity in ecosystems such as forests , coral reefs
    and in Arctic regions . Risks associated with large-scale singular events or tipping
    points, such as ice sheet instability or ecosystem loss from tropical forests,
    transition to high risk between 1.5°C to 2.5°C  and to very high risk between
    2.5°C to 4°C. The response of biogeochemical cycles to anthropogenic perturbations
    can be abrupt at regional scales and irreversible on decadal to century time scales.
    The probability of crossing uncertain regional thresholds increases with further
    warming.  Sea level rise is unavoidable for centuries to millennia due to continuing
    deep ocean warming and ice sheet melt, and sea levels will remain elevated for
    thousands of years . Global mean sea level rise will continue in the 21st century,
    with projected regional relative sea level rise within 20% of the global mean
    along two-thirds of the global coastline . The magnitude, the rate, the timing
    of threshold exceedances, and the long-term commitment of sea level rise depend
    on emissions, with higher emissions leading to greater and faster rates of sea
    level rise. Due to relative sea level rise, extreme sea level events that occurred
    once per century in the recent past are projected to occur at least annually at
    more than half of all tide gauge locations by 2100 and risks for coastal ecosystems,
    people and infrastructure will continue to increase beyond 2100. At sustained
    warming levels between 2°C and 3°C, the Greenland and West Antarctic ice sheets
    will be lost almost completely and irreversibly over multiple millennia. The probability
    and rate of ice mass loss increase with higher global surface temperatures. Over
    the next 2000 years, global mean sea level will rise by about 2 to 3 m if warming
    is limited to 1.5°C and 2 to 6 m if limited to 2°C . Projections of multi-millennial
    global mean sea level rise are consistent with reconstructed levels during past
    warm climate periods: global mean sea level was very likely 5 to 25 m higher than
    today roughly 3 million years ago, when global temperatures were 2.5°C to 4°C
    higher than 1850–1900. Further examples of unavoidable changes in the climate
    system due to multi-decadal or longer response timescales include continued glacier
    melt  and permafrost carbon loss.  The probability of low-likelihood outcomes
    associated with potentially very large impacts increases with higher global warming
    levels. Warming substantially above the assessed very likely range for a given
    scenario cannot be ruled out, and there is high confidence this would lead to
    regional changes greater than assessed in many aspects of the climate system.
    Low-likelihood, high-impact outcomes could occur at regional scales even for global
    warming within the very likely assessed range for a given GHG emissions scenario.
    Global mean sea level rise above the likely range – approaching 2 m by 2100 and
    in excess of 15 m by 2300 under a very high GHG emissions scenario  – cannot be
    ruled out due to deep uncertainty in ice-sheet processes 123 and would have severe
    impacts on populations in low elevation coastal zones. If global warming increases,
    some compound extreme events 124 will become more frequent, with higher likelihood
    of unprecedented intensities, durations or spatial extent. The Atlantic Meridional
    Overturning Circulation is very likely to weaken over the 21st century for all
    considered scenarios, however an abrupt collapse is not expected before 2100 .
    If such a low probability event were to occur, it would very likely cause abrupt
    shifts in regional weather patterns and water cycle, such as a southward shift
    in the tropical rain belt, and large impacts on ecosystems and human activities.
    A sequence of large explosive volcanic eruptions within decades, as have occurred
    in the past, is a low-likelihood high-impact event that would lead to substantial
    cooling globally and regional climate perturbations over several decades.'
  B.4.1:
  - Long-term Adaptation Options and Limits  With increasing warming, adaptation options
    will become more constrained and less effective. At higher levels of warming,
    losses and damages will increase, and additional human and natural systems will
    reach adaptation limits. Integrated, cross-cutting multi-sectoral solutions increase
    the effectiveness of adaptation. Maladaptation can create lock-ins of vulnerability,
    exposure and risks but can be avoided by long-term planning and the implementation
    of adaptation actions that are flexible, multi-sectoral and inclusive. The effectiveness
    of adaptation to reduce climate risk is documented for specific contexts, sectors
    and regions and will decrease with increasing warming 125 . For example, common
    adaptation responses in agriculture – adopting improved cultivars and agronomic
    practices, and changes in cropping patterns and crop systems – will become less
    effective from 2°C to higher levels of warming. The effectiveness of most water-related
    adaptation options to reduce projected risks declines with increasing warming.
    Adaptations for hydropower and thermo-electric power generation are effective
    in most regions up to 1.5°C to 2°C, with decreasing effectiveness at higher levels
    of warming . Ecosystem-based Adaptation is vulnerable to climate change impacts,
    with effectiveness declining with increasing global warming. Globally, adaptation
    options related to agroforestry and forestry have a sharp decline in effectiveness
    at 3°C, with a substantial increase in residual risk.  With increasing global
    warming, more limits to adaptation will be reached and losses and damages, strongly
    concentrated among the poorest vulnerable populations, will increase. Already
    below 1.5°C, autonomous and evolutionary adaptation responses by terrestrial and
    aquatic ecosystems will increasingly face hard limits. Above 1.5°C, some ecosystem-based
    adaptation measures will lose their effectiveness in providing benefits to people
    as these ecosystems will reach hard adaptation limits. Adaptation to address the
    risks of heat stress, heat mortality and reduced capacities for outdoor work for
    humans face soft and hard limits across regions that become significantly more
    severe at 1.5°C, and are particularly relevant for regions with warm climates.
    Above 1.5°C global warming level, limited freshwater resources pose potential
    hard limits for small islands and for regions dependent on glacier and snow melt
    . By 2°C, soft limits are projected for multiple staple crops, particularly in
    tropical regions. By 3°C, soft limits are projected for some water management
    measures for many regions, with hard limits projected for parts of Europe .  Integrated,
    cross-cutting multi-sectoral solutions increase the effectiveness of adaptation.
    For example, inclusive, integrated and long-term planning at local, municipal,
    sub-national and national scales, together with effective regulation and monitoring
    systems and financial and technological resources and capabilities foster urban
    and rural system transition. There are a range of cross-cutting adaptation options,
    such as disaster risk management, early warning systems, climate services and
    risk spreading and sharing that have broad applicability across sectors and provide
    greater benefits to other adaptation options when combined. Transitioning from
    incremental to transformational adaptation, and addressing a range of constraints,
    primarily in the financial, governance, institutional and policy domains, can
    help overcome soft adaptation limits. However, adaptation does not prevent all
    losses and damages, even with effective adaptation and before reaching soft and
    hard limits.  Maladaptive responses to climate change can create lock-ins of vulnerability,
    exposure and risks that are difficult and expensive to change and exacerbate existing
    inequalities. Actions that focus on sectors and risks in isolation and on short-term
    gains often lead to maladaptation. Adaptation options can become maladaptive due
    to their environmental impacts that constrain ecosystem services and decrease
    biodiversity and ecosystem resilience to climate change or by causing adverse
    outcomes for different groups, exacerbating inequity. Maladaptation can be avoided
    by flexible, multi-sectoral, inclusive and long-term planning and implementation
    of adaptation actions with benefits to many sectors and systems.  Sea level rise
    poses a distinctive and severe adaptation challenge as it implies both dealing
    with slow onset changes and increases in the frequency and magnitude of extreme
    sea level events . Such adaptation challenges would occur much earlier under high
    rates of sea level rise. Responses to ongoing sea level rise and land subsidence
    include protection, accommodation, advance and planned relocation. These responses
    are more effective if combined and/or sequenced, planned well ahead, aligned with
    sociocultural values and underpinned by inclusive community engagement processes.
    Ecosystem-based solutions such as wetlands provide co-benefits for the environment
    and climate mitigation, and reduce costs for flood defences , but have site-specific
    physical limits, at least above 1.5ºC of global warming and lose effectiveness
    at high rates of sea level rise beyond 0.5 to 1 cm yr -1. Seawalls can be maladaptive
    as they effectively reduce impacts in the short term but can also result in lock-ins
    and increase exposure to climate risks in the long term unless they are integrated
    into a long-term adaptive plan.
  - 'The Timing and Urgency of Climate Action  The magnitude and rate of climate change
    and associated risks depend strongly on near-term mitigation and adaptation actions
    . Global warming is more likely than not to reach 1.5°C between 2021 and 2040
    even under the very low GHG emission scenarios, and likely or very likely to exceed
    1.5°C under higher emissions scenarios 141. Many adaptation options have medium
    or high feasibility up to 1.5°C , but hard limits to adaptation have already been
    reached in some ecosystems and the effectiveness of adaptation to reduce climate
    risk will decrease with increasing warming. Societal choices and actions implemented
    in this decade determine the extent to which medium- and long-term pathways will
    deliver higher or lower climate resilient development. Climate resilient development
    prospects are increasingly limited if current greenhouse gas emissions do not
    rapidly decline, especially if 1.5°C global warming is exceeded in the near term.
    Without urgent, effective and equitable adaptation and mitigation actions, climate
    change increasingly threatens the health and livelihoods of people around the
    globe, ecosystem health, and biodiversity, with severe adverse consequences for
    current and future generations. .  In modelled pathways that limit warming to
    1.5°C with no or limited overshoot and in those that limit warming to 2°C, assuming
    immediate actions, global GHG emissions are projected to peak in the early 2020s
    followed by rapid and deep GHG emissions reductions 142 . In pathways that limit
    warming to 1.5°C with no or limited overshoot, net global GHG emissions are projected
    to fall by 43 [34 to 60]%143 below 2019 levels by 2030, 60 [49 to 77]% by 2035,
    69 [58 to 90]% by 2040 and 84 [73 to 98]% by 2050 144. Global modelled pathways
    that limit warming to 2°C have reductions in GHG emissions below 2019 levels of
    21 [1 to 42]% by 2030, 35 [22 to 55] % by 2035, 46 [34 to 63] % by 2040 and 64
    [53 to 77]% by 2050145. Global GHG emissions associated with NDCs announced prior
    to COP26 would make it likely that warming would exceed 1.5°C and limiting warming
    to 2°C would then imply a rapid acceleration of emission reductions during 2030–2050,
    around 70% faster than in pathways where immediate action is taken to limit warming
    to 2°C Continued investments in unabated high-emitting infrastructure and limited
    development and deployment of low-emitting alternatives prior to 2030 would act
    as barriers to this acceleration and increase feasibility risks.  All global modelled
    pathways that limit warming to 2°C or lower by 2100 involve reductions in both
    net CO 2 emissions and non-CO 2 emissions. For example, in pathways that limit
    warming to 1.5°C with no or limited overshoot, global CH4 emissions are reduced
    by 34 [21 to 57]% below 2019 levels by 2030 and by 44 [31 to 63]% in 2040. Global
    CH 4 emissions are reduced by 24 [9 to 53]% below 2019 levels by 2030 and by 37
    [20 to 60]% in 2040 in modelled pathways that limit warming to 2°C with action
    starting in 2020.  All global modelled pathways that limit warming to 2°C or lower
    by 2100 involve GHG emission reductions in all sectors . The contributions of
    different sectors vary across modelled mitigation pathways. In most global modelled
    mitigation pathways, emissions from land-use, land-use change and forestry, via
    reforestation and reduced deforestation, and from the energy supply sector reach
    net zero CO2 emissions earlier than the buildings, industry and transport sectors.
    Strategies can rely on combinations of different options, but doing less in one
    sector needs to be compensated by further reductions in other sectors if warming
    is to be limited.  Without rapid, deep and sustained mitigation and accelerated
    adaptation actions, losses and damages will continue to increase, including projected
    adverse impacts in Africa, LDCs, SIDS, Central and South America , Asia and the
    Arctic, and will disproportionately affect the most vulnerable populations .  '
  - 'Benefits of Strengthening Near-Term Action  Accelerated implementation of adaptation
    will improve well-being by reducing losses and damages, especially for vulnerable
    populations. Deep, rapid, and sustained mitigation actions would reduce future
    adaptation costs and losses and damages, enhance sustainable development co-benefits,
    avoid locking-in emission sources, and reduce stranded assets and irreversible
    climate changes. These near-term actions involve higher up-front investments and
    disruptive changes, which can be moderated by a range of enabling conditions and
    removal or reduction of barriers to feasibility. Accelerated implementation of
    adaptation responses will bring benefits to human well-being. As adaptation options
    often have long implementation times, long-term planning and accelerated implementation,
    particularly in this decade, is important to close adaptation gaps, recognising
    that constraints remain for some regions. The benefits to vulnerable populations
    would be high .  Near-term actions that limit global warming to close to 1.5°C
    would substantially reduce projected losses and damages related to climate change
    in human systems and ecosystems, compared to higher warming levels, but cannot
    eliminate them all . The magnitude and rate of climate change and associated risks
    depend strongly on near-term mitigation and adaptation actions, and projected
    adverse impacts and related losses and damages escalate with every increment of
    global warming. Delayed mitigation action will further increase global warming
    which will decrease the effectiveness of many adaptation options, including Ecosystem-based
    Adaptation and many water-related options, as well as increasing mitigation feasibility
    risks, such as for options based on ecosystems. Comprehensive, effective, and
    innovative responses integrating adaptation and mitigation can harness synergies
    and reduce trade-offs between adaptation and mitigation, as well as in meeting
    requirements for financing .  Mitigation actions will have other sustainable development
    co-benefits. Mitigation will improve air quality and human health in the near
    term notably because many air pollutants are co-emitted by GHG emitting sectors
    and because methane emissions leads to surface ozone formation. The benefits from
    air quality improvement include prevention of air pollution-related premature
    deaths, chronic diseases and damages to ecosystems and crops. The economic benefits
    for human health from air quality improvement arising from mitigation action can
    be of the same order of magnitude as mitigation costs, and potentially even larger
    . As methane has a short lifetime but is a potent GHG, strong, rapid and sustained
    reductions in methane emissions can limit near-term warming and improve air quality
    by reducing global surface ozone.  Challenges from delayed adaptation and mitigation
    actions include the risk of cost escalation, lock-in of infrastructure, stranded
    assets, and reduced feasibility and effectiveness of adaptation and mitigation
    options. The continued installation of unabated fossil fuel infrastructure will
    ‘lock-in’ GHG emissions. Limiting global warming to 2°C or below will leave a
    substantial amount of fossil fuels unburned and could strand considerable fossil
    fuel infrastructure , with globally discounted value projected to be around USD
    1 to 4 trillion from 2015 to 2050. Early actions would limit the size of these
    stranded assets, whereas delayed actions with continued investments in unabated
    high-emitting infrastructure and limited development and deployment of low-emitting
    alternatives prior to 2030 would raise future stranded assets to the higher end
    of the range – thereby acting as barriers and increasing political economy feasibility
    risks that may jeopardise efforts to limit global warming. .  Scaling-up near-term
    climate actions will mobilise a mix of low-cost and high-cost options. High-cost
    options, as in energy and infrastructure, are needed to avoid future lock-ins,
    foster innovation and initiate transformational changes. Climate resilient development
    pathways in support of sustainable development for all are shaped by equity, and
    social and climate justice. Embedding effective and equitable adaptation and mitigation
    in development planning can reduce vulnerability, conserve and restore ecosystems,
    and enable climate resilient development. This is especially challenging in localities
    with persistent development gaps and limited resources.  Scaling-up climate action
    may generate disruptive changes in economic structure with distributional consequences
    and need to reconcile divergent interests, values and worldviews, within and between
    countries. Deeper fiscal, financial, institutional and regulatory reforms can
    offset such adverse effects and unlock mitigation potentials. Societal choices
    and actions implemented in this decade will determine the extent to which medium
    and long-term development pathways will deliver higher or lower climate resilient
    development outcomes.  Enabling conditions would need to be strengthened in the
    nearterm and barriers reduced or removed to realise opportunities for deep and
    rapid adaptation and mitigation actions and climate resilient development. These
    enabling conditions are differentiated by national, regional and local circumstances
    and geographies, according to capabilities, and include: equity and inclusion
    in climate action, rapid and far-reaching transitions in sectors and system ,
    measures to achieve synergies and reduce tradeoffs with sustainable development
    goals, governance and policy improvements, access to finance, improved international
    cooperation and technology improvements, and integration of near-term actions
    across sectors, systems and regions.  Barriers to feasibility would need to be
    reduced or removed to deploy mitigation and adaptation options at scale. Many
    limits to feasibility and effectiveness of responses can be overcome by addressing
    a range of barriers, including economic, technological, institutional, social,
    environmental and geophysical barriers. The feasibility and effectiveness of options
    increase with integrated, multi-sectoral solutions that differentiate responses
    based on climate risk, cut across systems and address social inequities. Strengthened
    near-term actions in modelled cost-effective pathways that limit global warming
    to 2°C or lower, reduce the overall risk to the feasibility of the system transitions,
    compared to modelled pathways with delayed or uncoordinated action.  Integrating
    ambitious climate actions with macroeconomic policies under global uncertainty
    would provide benefits . This encompasses three main directions: economy-wide
    mainstreaming packages supporting options to improved sustainable low-emission
    economic recovery, development and job creation programs  safety nets and social
    protection in the transition; and broadened access to finance, technology and
    capacity-building and coordinated support to low-emission infrastructure , especially
    in developing regions, and under debt stress .'
  B.4.2:
  - Adaptation Gaps and Barriers  Despite progress, adaptation gaps exist between
    current levels of adaptation and levels needed to respond to impacts and reduce
    climate risks. While progress in adaptation implementation is observed across
    all sectors and regions , many adaptation initiatives prioritise immediate and
    near-term climate risk reduction, e.g., through hard flood protection, which reduces
    the opportunity for transformational adaptation . Most observed adaptation is
    fragmented, small in scale, incremental, sector-specific, and focused more on
    planning rather than implementation. Further, observed adaptation is unequally
    distributed across regions and the largest adaptation gaps exist among lower population
    income groups. In the urban context, the largest adaptation gaps exist in projects
    that manage complex risks, for example in the food–energy–water–health nexus or
    the inter-relationships of air quality and climate risk. Many funding, knowledge
    and practice gaps remain for effective implementation, monitoring and evaluation
    and current adaptation efforts are not expected to meet existing goals. At current
    rates of adaptation planning and implementation the adaptation gap will continue
    to grow.  Soft and hard adaptation limits 100 have already been reached in some
    sectors and regions, in spite of adaptation having buffered some climate impacts.
    Ecosystems already reaching hard adaptation limits include some warm water coral
    reefs, some coastal wetlands, some rainforests, and some polar and mountain ecosystems.
    Individuals and households in low lying coastal areas in Australasia and Small
    Islands and smallholder farmers in Central and South America, Africa, Europe and
    Asia have reached soft limits, resulting from financial, governance, institutional
    and policy constraints and can be overcome by addressing these constraints. Transitioning
    from incremental to transformational adaptation can help overcome soft adaptation
    limits .  Adaptation does not prevent all losses and damages, even with effective
    adaptation and before reaching soft and hard limits. Losses and damages are unequally
    distributed across systems, regions and sectors and are not comprehensively addressed
    by current financial, governance and institutional arrangements, particularly
    in vulnerable developing countries.  There is increased evidence of maladaptation
    in various sectors and regions. Examples of maladaptation are observed in urban
    areas , agriculture , ecosystems (e.g. fire suppression in naturally
  - Long-term Adaptation Options and Limits  With increasing warming, adaptation options
    will become more constrained and less effective. At higher levels of warming,
    losses and damages will increase, and additional human and natural systems will
    reach adaptation limits. Integrated, cross-cutting multi-sectoral solutions increase
    the effectiveness of adaptation. Maladaptation can create lock-ins of vulnerability,
    exposure and risks but can be avoided by long-term planning and the implementation
    of adaptation actions that are flexible, multi-sectoral and inclusive. The effectiveness
    of adaptation to reduce climate risk is documented for specific contexts, sectors
    and regions and will decrease with increasing warming 125 . For example, common
    adaptation responses in agriculture – adopting improved cultivars and agronomic
    practices, and changes in cropping patterns and crop systems – will become less
    effective from 2°C to higher levels of warming. The effectiveness of most water-related
    adaptation options to reduce projected risks declines with increasing warming.
    Adaptations for hydropower and thermo-electric power generation are effective
    in most regions up to 1.5°C to 2°C, with decreasing effectiveness at higher levels
    of warming . Ecosystem-based Adaptation is vulnerable to climate change impacts,
    with effectiveness declining with increasing global warming. Globally, adaptation
    options related to agroforestry and forestry have a sharp decline in effectiveness
    at 3°C, with a substantial increase in residual risk.  With increasing global
    warming, more limits to adaptation will be reached and losses and damages, strongly
    concentrated among the poorest vulnerable populations, will increase. Already
    below 1.5°C, autonomous and evolutionary adaptation responses by terrestrial and
    aquatic ecosystems will increasingly face hard limits. Above 1.5°C, some ecosystem-based
    adaptation measures will lose their effectiveness in providing benefits to people
    as these ecosystems will reach hard adaptation limits. Adaptation to address the
    risks of heat stress, heat mortality and reduced capacities for outdoor work for
    humans face soft and hard limits across regions that become significantly more
    severe at 1.5°C, and are particularly relevant for regions with warm climates.
    Above 1.5°C global warming level, limited freshwater resources pose potential
    hard limits for small islands and for regions dependent on glacier and snow melt
    . By 2°C, soft limits are projected for multiple staple crops, particularly in
    tropical regions. By 3°C, soft limits are projected for some water management
    measures for many regions, with hard limits projected for parts of Europe .  Integrated,
    cross-cutting multi-sectoral solutions increase the effectiveness of adaptation.
    For example, inclusive, integrated and long-term planning at local, municipal,
    sub-national and national scales, together with effective regulation and monitoring
    systems and financial and technological resources and capabilities foster urban
    and rural system transition. There are a range of cross-cutting adaptation options,
    such as disaster risk management, early warning systems, climate services and
    risk spreading and sharing that have broad applicability across sectors and provide
    greater benefits to other adaptation options when combined. Transitioning from
    incremental to transformational adaptation, and addressing a range of constraints,
    primarily in the financial, governance, institutional and policy domains, can
    help overcome soft adaptation limits. However, adaptation does not prevent all
    losses and damages, even with effective adaptation and before reaching soft and
    hard limits.  Maladaptive responses to climate change can create lock-ins of vulnerability,
    exposure and risks that are difficult and expensive to change and exacerbate existing
    inequalities. Actions that focus on sectors and risks in isolation and on short-term
    gains often lead to maladaptation. Adaptation options can become maladaptive due
    to their environmental impacts that constrain ecosystem services and decrease
    biodiversity and ecosystem resilience to climate change or by causing adverse
    outcomes for different groups, exacerbating inequity. Maladaptation can be avoided
    by flexible, multi-sectoral, inclusive and long-term planning and implementation
    of adaptation actions with benefits to many sectors and systems.  Sea level rise
    poses a distinctive and severe adaptation challenge as it implies both dealing
    with slow onset changes and increases in the frequency and magnitude of extreme
    sea level events . Such adaptation challenges would occur much earlier under high
    rates of sea level rise. Responses to ongoing sea level rise and land subsidence
    include protection, accommodation, advance and planned relocation. These responses
    are more effective if combined and/or sequenced, planned well ahead, aligned with
    sociocultural values and underpinned by inclusive community engagement processes.
    Ecosystem-based solutions such as wetlands provide co-benefits for the environment
    and climate mitigation, and reduce costs for flood defences , but have site-specific
    physical limits, at least above 1.5ºC of global warming and lose effectiveness
    at high rates of sea level rise beyond 0.5 to 1 cm yr -1. Seawalls can be maladaptive
    as they effectively reduce impacts in the short term but can also result in lock-ins
    and increase exposure to climate risks in the long term unless they are integrated
    into a long-term adaptive plan.
  - 'Near-Term Risks  Many changes in the climate system, including extreme events,
    will become larger in the near term with increasing global warming. Multiple climatic
    and non-climatic risks will interact, resulting in increased compounding and cascading
    impacts becoming more difficult to manage. Losses and damages will increase with
    increasing global warming, while strongly concentrated among the poorest vulnerable
    populations. Continuing with current unsustainable development patterns would
    increase exposure and vulnerability of ecosystems and people to climate hazards.
    Global warming will continue to increase in the near term mainly due to increased
    cumulative CO 2 emissions in nearly all considered scenarios and pathways. In
    the near term, every region in the world is projected to face further increases
    in climate hazards , increasing multiple risks to ecosystems and humans. In the
    near term, natural variability will modulate human-caused changes, either attenuating
    or amplifying projected changes, especially at regional scales, with little effect
    on centennial global warming. Those modulations are important to consider in adaptation
    planning. Global surface temperature in any single year can vary above or below
    the long-term human-induced trend, due to natural variability. By 2030, global
    surface temperature in any individual year could exceed 1.5°C relative to 1850–1900
    with a probability between 40% and 60%, across the five scenarios assessed in
    WGI. The occurrence of individual years with global surface temperature change
    above a certain level does not imply that this global warming level has been reached.
    If a large explosive volcanic eruption were to occur in the near term 150, it
    would temporarily and partially mask human-caused climate change by reducing global
    surface temperature and precipitation, especially over land, for one to three
    years.  The level of risk for humans and ecosystems will depend on near-term trends
    in vulnerability, exposure, level of socio-economic development and adaptation.
    In the near term, many climate-associated risks to natural and human systems depend
    more strongly on changes in these systems’ vulnerability and exposure than on
    differences in climate hazards between emissions scenarios . Future exposure to
    climatic hazards is increasing globally due to socio-economic development trends
    including growing inequality, and when urbanisation or migration increase exposure
    . Urbanisation increases hot extremes  and precipitation runoff intensity. Increasing
    urbanisation in low-lying and coastal zones will be a major driver of increasing
    exposure to extreme riverflow events and sea level rise hazards, increasing risks.
    Vulnerability will also rise rapidly in low-lying Small Island Developing States
    and atolls in the context of sea level rise . Human vulnerability will concentrate
    in informal settlements and rapidly growing smaller settlements; and vulnerability
    in rural areas will be heightened by reduced habitability and high reliance on
    climate-sensitive livelihoods. Human and ecosystem vulnerability are interdependent.
    Vulnerability to climate change for ecosystems will be strongly influenced by
    past, present, and future patterns of human development, including from unsustainable
    consumption and production, increasing demographic pressures, and persistent unsustainable
    use and management of land, ocean, and water. Several near-term risks can be moderated
    with adaptation.  Principal hazards and associated risks expected in the near
    term are: • Increased intensity and frequency of hot extremes and dangerous heat-humidity
    conditions, with increased human mortality, morbidity, and labour productivity
    loss.  • Increasing frequency of marine heatwaves will increase risks of biodiversity
    loss in the oceans, including from mass mortality events.  • Near-term risks for
    biodiversity loss are moderate to high in forest ecosystems and kelp and seagrass
    ecosystems and are high to very high in Arctic sea-ice and terrestrial ecosystems
    and warm-water coral reefs.  • More intense and frequent extreme rainfall and
    associated flooding in many regions including coastal and other low-lying cities
    , and increased proportion of and peak wind speeds of intense tropical cyclones.  •
    High risks from dryland water scarcity, wildfire damage, and permafrost degradation.  •
    Continued sea level rise and increased frequency and magnitude of extreme sea
    level events encroaching on coastal human settlements and damaging coastal infrastructure
    , committing low-lying coastal ecosystems to submergence and loss, expanding land
    salinization, with cascading to risks to livelihoods, health, well-being, cultural
    values, food and water security.  • Climate change will significantly increase
    ill health and premature deaths from the near to long term. Further warming will
    increase climate-sensitive food-borne, water-borne, and vector-borne disease risks,
    and mental health challenges including anxiety and stress.  Cryosphere-related
    changes in floods, landslides, and water availability have the potential to lead
    to severe consequences for people, infrastructure and the economy in most mountain
    regions .  • The projected increase in frequency and intensity of heavy precipitation
    will increase rain-generated local flooding.  Multiple climate change risks will
    increasingly compound and cascade in the near term. Many regions are projected
    to experience an increase in the probability of compound events with higher global
    warming including concurrent heatwaves and drought. Risks to health and food production
    will be made more severe from the interaction of sudden food production losses
    from heat and drought, exacerbated by heatinduced labour productivity losses.
    These interacting impacts will increase food prices, reduce household incomes,
    and lead to health risks of malnutrition and climate-related mortality with no
    or low levels of adaptation, especially in tropical regions . Concurrent and cascading
    risks from climate change to food systems, human settlements, infrastructure and
    health will make these risks more severe and more difficult to manage, including
    when interacting with non-climatic risk drivers such as competition for land between
    urban expansion and food production, and pandemics . Loss of ecosystems and their
    services has cascading and long-term impacts on people globally, especially for
    Indigenous Peoples and local communities who are directly dependent on ecosystems,
    to meet basic needs. Increasing transboundary risks are projected across the food,
    energy and water sectors as impacts from weather and climate extremes propagate
    through supply-chains, markets, and natural resource flows and may interact with
    impacts from other crises such as pandemics. Risks also arise from some responses
    intended to reduce the risks of climate change, including risks from maladaptation
    and adverse side effects of some emissions reduction and carbon dioxide removal
    measures, such as afforestation of naturally unforested land or poorly implemented
    bioenergy compounding climate-related risks to biodiversity, food and water security,
    and livelihoods.  With every increment of global warming losses and damages will
    increase, become increasingly difficult to avoid and be strongly concentrated
    among the poorest vulnerable populations. Adaptation does not prevent all losses
    and damages, even with effective adaptation and before reaching soft and hard
    limits. Losses and damages will be unequally distributed across systems, regions
    and sectors and are not comprehensively addressed by current financial, governance
    and institutional arrangements, particularly in vulnerable developing countries.
    .'
  B.4.3:
  - Adaptation Gaps and Barriers  Despite progress, adaptation gaps exist between
    current levels of adaptation and levels needed to respond to impacts and reduce
    climate risks. While progress in adaptation implementation is observed across
    all sectors and regions , many adaptation initiatives prioritise immediate and
    near-term climate risk reduction, e.g., through hard flood protection, which reduces
    the opportunity for transformational adaptation . Most observed adaptation is
    fragmented, small in scale, incremental, sector-specific, and focused more on
    planning rather than implementation. Further, observed adaptation is unequally
    distributed across regions and the largest adaptation gaps exist among lower population
    income groups. In the urban context, the largest adaptation gaps exist in projects
    that manage complex risks, for example in the food–energy–water–health nexus or
    the inter-relationships of air quality and climate risk. Many funding, knowledge
    and practice gaps remain for effective implementation, monitoring and evaluation
    and current adaptation efforts are not expected to meet existing goals. At current
    rates of adaptation planning and implementation the adaptation gap will continue
    to grow.  Soft and hard adaptation limits 100 have already been reached in some
    sectors and regions, in spite of adaptation having buffered some climate impacts.
    Ecosystems already reaching hard adaptation limits include some warm water coral
    reefs, some coastal wetlands, some rainforests, and some polar and mountain ecosystems.
    Individuals and households in low lying coastal areas in Australasia and Small
    Islands and smallholder farmers in Central and South America, Africa, Europe and
    Asia have reached soft limits, resulting from financial, governance, institutional
    and policy constraints and can be overcome by addressing these constraints. Transitioning
    from incremental to transformational adaptation can help overcome soft adaptation
    limits .  Adaptation does not prevent all losses and damages, even with effective
    adaptation and before reaching soft and hard limits. Losses and damages are unequally
    distributed across systems, regions and sectors and are not comprehensively addressed
    by current financial, governance and institutional arrangements, particularly
    in vulnerable developing countries.  There is increased evidence of maladaptation
    in various sectors and regions. Examples of maladaptation are observed in urban
    areas , agriculture , ecosystems (e.g. fire suppression in naturally
  - Long-term Adaptation Options and Limits  With increasing warming, adaptation options
    will become more constrained and less effective. At higher levels of warming,
    losses and damages will increase, and additional human and natural systems will
    reach adaptation limits. Integrated, cross-cutting multi-sectoral solutions increase
    the effectiveness of adaptation. Maladaptation can create lock-ins of vulnerability,
    exposure and risks but can be avoided by long-term planning and the implementation
    of adaptation actions that are flexible, multi-sectoral and inclusive. The effectiveness
    of adaptation to reduce climate risk is documented for specific contexts, sectors
    and regions and will decrease with increasing warming 125 . For example, common
    adaptation responses in agriculture – adopting improved cultivars and agronomic
    practices, and changes in cropping patterns and crop systems – will become less
    effective from 2°C to higher levels of warming. The effectiveness of most water-related
    adaptation options to reduce projected risks declines with increasing warming.
    Adaptations for hydropower and thermo-electric power generation are effective
    in most regions up to 1.5°C to 2°C, with decreasing effectiveness at higher levels
    of warming . Ecosystem-based Adaptation is vulnerable to climate change impacts,
    with effectiveness declining with increasing global warming. Globally, adaptation
    options related to agroforestry and forestry have a sharp decline in effectiveness
    at 3°C, with a substantial increase in residual risk.  With increasing global
    warming, more limits to adaptation will be reached and losses and damages, strongly
    concentrated among the poorest vulnerable populations, will increase. Already
    below 1.5°C, autonomous and evolutionary adaptation responses by terrestrial and
    aquatic ecosystems will increasingly face hard limits. Above 1.5°C, some ecosystem-based
    adaptation measures will lose their effectiveness in providing benefits to people
    as these ecosystems will reach hard adaptation limits. Adaptation to address the
    risks of heat stress, heat mortality and reduced capacities for outdoor work for
    humans face soft and hard limits across regions that become significantly more
    severe at 1.5°C, and are particularly relevant for regions with warm climates.
    Above 1.5°C global warming level, limited freshwater resources pose potential
    hard limits for small islands and for regions dependent on glacier and snow melt
    . By 2°C, soft limits are projected for multiple staple crops, particularly in
    tropical regions. By 3°C, soft limits are projected for some water management
    measures for many regions, with hard limits projected for parts of Europe .  Integrated,
    cross-cutting multi-sectoral solutions increase the effectiveness of adaptation.
    For example, inclusive, integrated and long-term planning at local, municipal,
    sub-national and national scales, together with effective regulation and monitoring
    systems and financial and technological resources and capabilities foster urban
    and rural system transition. There are a range of cross-cutting adaptation options,
    such as disaster risk management, early warning systems, climate services and
    risk spreading and sharing that have broad applicability across sectors and provide
    greater benefits to other adaptation options when combined. Transitioning from
    incremental to transformational adaptation, and addressing a range of constraints,
    primarily in the financial, governance, institutional and policy domains, can
    help overcome soft adaptation limits. However, adaptation does not prevent all
    losses and damages, even with effective adaptation and before reaching soft and
    hard limits.  Maladaptive responses to climate change can create lock-ins of vulnerability,
    exposure and risks that are difficult and expensive to change and exacerbate existing
    inequalities. Actions that focus on sectors and risks in isolation and on short-term
    gains often lead to maladaptation. Adaptation options can become maladaptive due
    to their environmental impacts that constrain ecosystem services and decrease
    biodiversity and ecosystem resilience to climate change or by causing adverse
    outcomes for different groups, exacerbating inequity. Maladaptation can be avoided
    by flexible, multi-sectoral, inclusive and long-term planning and implementation
    of adaptation actions with benefits to many sectors and systems.  Sea level rise
    poses a distinctive and severe adaptation challenge as it implies both dealing
    with slow onset changes and increases in the frequency and magnitude of extreme
    sea level events . Such adaptation challenges would occur much earlier under high
    rates of sea level rise. Responses to ongoing sea level rise and land subsidence
    include protection, accommodation, advance and planned relocation. These responses
    are more effective if combined and/or sequenced, planned well ahead, aligned with
    sociocultural values and underpinned by inclusive community engagement processes.
    Ecosystem-based solutions such as wetlands provide co-benefits for the environment
    and climate mitigation, and reduce costs for flood defences , but have site-specific
    physical limits, at least above 1.5ºC of global warming and lose effectiveness
    at high rates of sea level rise beyond 0.5 to 1 cm yr -1. Seawalls can be maladaptive
    as they effectively reduce impacts in the short term but can also result in lock-ins
    and increase exposure to climate risks in the long term unless they are integrated
    into a long-term adaptive plan.
  B.5.1:
  - Long-term Climate Change  The uncertainty range on assessed future changes in
    global surface temperature is narrower than in the AR5. For the first time in
    an IPCC assessment cycle, multi-model projections of global surface temperature,
    ocean warming and sea level are constrained using observations and the assessed
    climate sensitivity. The likely range of equilibrium climate sensitivity has been
    narrowed to 2.5°C to 4.0°C based on multiple lines of evidence , including improved
    understanding of cloud feedbacks. For related emissions scenarios, this leads
    to narrower uncertainty ranges for long-term projected global temperature change
    than in AR5.  Future warming depends on future GHG emissions, with cumulative
    net CO 2 dominating. The assessed best estimates and very likely ranges of warming
    for 2081-2100 with respect to 1850–1900 vary from 1.4 [1.0 to 1.8]°C in the very
    low GHG emissions scenario to 2.7 [2.1 to 3.5]°C in the intermediate GHG emissions
    scenario and 4.4 [3.3 to 5.7]°C in the very high GHG emissions scenario 113 .  Modelled
    pathways consistent with the continuation of policies implemented by the end of
    2020 lead to global warming of 3.2 [2.2 to 3.5]°C by 2100 . Pathways of >4°C by
    2100 would imply a reversal of current technology and/or mitigation policy trends
    . However, such warming could occur in emissions pathways consistent with policies
    implemented by the end of 2020 if climate sensitivity or carbon cycle feedbacks
    are higher than the best estimate.  Global warming will continue to increase in
    the near term in nearly all considered scenarios and modelled pathways. Deep,
    rapid, and sustained GHG emissions reductions, reaching net zero CO2 emissions
    and including strong emissions reductions of other GHGs, in particular CH4, are
    necessary to limit warming to 1.5°C or less than 2°C by the end of century . The
    best estimate of reaching 1.5°C of global warming lies in the first half of the
    2030s in most of the considered scenarios and modelled pathways 114. In the very
    low GHG emissions scenario, CO 2 emissions reach net zero around 2050 and the
    best-estimate end-of-century warming is 1.4°C, after a temporary overshoot of
    no more than 0.1°C above 1.5°C global warming. Global warming of 2°C will be exceeded
    during the 21st century unless deep reductions in CO 2 and other GHG emissions
    occur in the coming decades. Deep, rapid, and sustained reductions in GHG emissions
    would lead to improvements in air quality within a few years, to reductions in
    trends of global surface temperature discernible after around 20 years, and over
    longer time periods for many other climate impact-drivers 115 . Targeted reductions
    of air pollutant emissions lead to more rapid improvements in air quality compared
    to reductions in GHG emissions only, but in the long term, further improvements
    are projected in scenarios that combine efforts to reduce air pollutants as well
    as GHG emissions 116 .   Changes in short-lived climate forcers resulting from
    the five considered scenarios lead to an additional net global warming in the
    near and long term. Simultaneous stringent climate change mitigation and air pollution
    control olicies limit this additional warming and lead to strong benefits for
    air quality. In high and very high GHG emissions scenarios, combined changes in
    SLCF emissions, such as CH 4, aerosol and ozone precursors, lead to a net global
    warming by 2100 of likely 0.4°C to 0.9°C relative to 2019. This is due to projected
    increases in atmospheric concentration of CH4, tropospheric ozone, hydrofluorocarbons
    and, when strong air pollution control is considered, reductions of cooling aerosols.
    In low and very low GHG emissions scenarios, air pollution control policies, reductions
    in CH 4 and other ozone precursors lead to a net cooling, whereas reductions in
    anthropogenic cooling aerosols lead to a net warming. Altogether, this causes
    a likely net warming of 0.0°C to 0.3°C due to SLCF changes in 2100 relative to
    2019 and strong reductions in global surface ozone and particulate matter .  Continued
    GHG emissions will further affect all major climate system components, and many
    changes will be irreversible on centennial to millennial time scales. Many changes
    in the climate system become larger in direct relation to increasing global warming.
    With every additional increment of global warming, changes in extremes continue
    to become larger. Additional warming will lead to more frequent and intense marine
    heatwaves and is projected to further amplify permafrost thawing and loss of seasonal
    snow cover, glaciers, land ice and Arctic sea ice. Continued global warming is
    projected to further intensify the global water cycle, including its variability,
    global monsoon precipitation , and very wet and very dry weather and climate events
    and seasons. The portion of global land experiencing detectable changes in seasonal
    mean precipitation is projected to increase with more variable precipitation and
    surface water flows over most land regions within seasons and from year to year
    . Many changes due to past and future GHG emissions are irreversible on centennial
    to millennial time scales, especially in the ocean, ice sheets and global sea
    level. Ocean acidification , ocean deoxygenation and global mean sea level will
    continue to increase in the 21st century, at rates dependent on future emissions.  With
    further global warming, every region is projected to increasingly experience concurrent
    and multiple changes in climatic impact-drivers. Increases in hot and decreases
    in cold climatic impact-drivers, such as temperature extremes, are projected in
    all regions. At 1.5°C global warming, heavy precipitation and flooding events
    are projected to intensify and become more frequent in most regions in Africa,
    Asia , North America and Europe . At 2°C or above, these changes expand to more
    regions and/or become more significant, and more frequent and/or severe agricultural
    and ecological droughts are projected in Europe, Africa, Australasia and North,
    Central and South America . Other projected regional changes include intensification
    of tropical cyclones and/or extratropical storms , and increases in aridity and
    fire weather . Compound heatwaves and droughts become likely more frequent, including
    concurrently at multiple locations.
  - Remaining Carbon Budgets  Limiting global temperature increase to a specific level
    requires limiting cumulative net CO2 emissions to within a finite carbon budget
    , along with strong reductions in other GHGs. For every 1000 GtCO2 emitted by
    human activity, global mean temperature rises by likely 0.27°C to 0.63°C. This
    relationship implies that there is a finite carbon budget that cannot be exceeded
    in order to limit warming to any given level.  The best estimates of the remaining
    carbon budget from the beginning of 2020 for limiting warming to 1.5°C with a
    50% likelihood is estimated to be 500 GtCO2; for 2°C this is 1150 GtCO2.128 Remaining
    carbon budgets have been quantified based on the assessed value of TCRE and its
    uncertainty, estimates of historical warming, climate system feedbacks such as
    emissions from thawing permafrost, and the global surface temperature change after
    global anthropogenic CO 2 emissions reach net zero, as well as variations in projected
    warming from non-CO2 emissions due in part to mitigation action. The stronger
    the reductions in non-CO2 emissions the lower the resulting temperatures are for
    a given RCB or the larger RCB for the same level of temperature change. For instance,
    the RCB for limiting warming to 1.5°C with a 50% likelihood could vary between
    300 to 600 GtCO 2 depending on non-CO 2 warming 129 . Limiting warming to 2°C
    with a 67% likelihood would imply a RCB of 1150 GtCO2 from the beginning of 2020.
    To stay below 2°C with a 50% likelihood, the RCB is higher, i.e., 1350 GtCO 2
    If the annual CO2 emissions between 2020–2030 stayed, on average, at the same
    level as 2019, the resulting cumulative emissions would almost exhaust the remaining
    carbon budget for 1.5°C, and exhaust more than a third of the remaining carbon
    budget for 2°C . Based on central estimates only, historical cumulative net CO2
    emissions between 1850 and 2019 amount to about four-fifths of the total carbon
    budget for a 50% probability of limiting global warming to 1.5°C and to about
    two-thirds of the total carbon budget for a 67% probability to limit global warming
    to 2°C.  In scenarios with increasing CO 2 emissions, the land and ocean carbon
    sinks are projected to be less effective at slowing the accumulation of CO2 in
    the atmosphere. While natural land and ocean carbon sinks are projected to take
    up, in absolute terms, a progressively larger amount of CO 2 under higher compared
    to lower CO2 emissions scenarios, they become less effective, that is, the proportion
    of emissions taken up by land and ocean decreases with increasing cumulative net
    CO2 emissions. Additional ecosystem responses to warming not yet fully included
    in climate models, such as GHG fluxes from wetlands, permafrost thaw, and wildfires,
    would further increase concentrations of these gases in the atmosphere . In scenarios
    where CO2 concentrations peak and decline during the 21st century, the land and
    ocean begin to take up less carbon in response to declining atmospheric CO2 concentrations  and
    turn into a weak net source by 2100 in the very low GHG emissions scenario 133.
  - 'Net Zero Emissions: Timing and Implications  From a physical science perspective,
    limiting human-caused global warming to a specific level requires limiting cumulative
    CO2 emissions, reaching net zero or net negative CO2 emissions, along with strong
    reductions of other GHG emissions . Global modelled pathways that reach and sustain
    net zero GHG emissions are projected to result in a gradual decline in surface
    temperature. Reaching net zero GHG emissions primarily requires deep reductions
    in CO2, methane, and other GHG emissions, and implies net negative CO2 emissions.134
    Carbon dioxide removal will be necessary to achieve net negative CO2 emissions
    135. Achieving global net zero CO2 emissions, with remaining anthropogenic CO
    2 emissions balanced by durably stored CO 2 from anthropogenic removal, is a requirement
    to stabilise CO2-induced global surface temperature increase . This is different
    from achieving net zero GHG emissions, where metric-weighted anthropogenic GHG
    emissions  equal CO 2 removal. Emissions pathways that reach and sustain net zero
    GHG emissions defined by the 100-year global warming potential imply net negative
    CO2 emissions and are projected to result in a gradual decline in surface temperature
    after an earlier peak. While reaching net zero CO2 or net zero GHG emissions requires
    deep and rapid reductions in gross emissions, the deployment of CDR to counterbalance
    hardto-abate residual emissions  is unavoidable .  In modelled pathways, the timing
    of net zero CO2 emissions, followed by net zero GHG emissions, depends on several
    variables, including the desired climate outcome, the mitigation strategy and
    the gases covered. Global net zero CO2 emissions are reached in the early 2050s
    in pathways that limit warming to 1.5°C with no or limited overshoot, and around
    the early 2070s in pathways that limit warming to 2°C. While non-CO2 GHG emissions
    are strongly reduced in all pathways that limit warming to 2°C or lower, residual
    emissions of CH4 and N2O and F-gases of about 8 [5–11] GtCO2 -eq yr -1 remain
    at the time of net zero GHG, counterbalanced by net negative CO2 emissions. As
    a result, net zero CO2 would be reached before net zero GHGs .'
  - 'Sectoral Contributions to Mitigation  All global modelled pathways that limit
    warming to 2°C or lower by 2100 involve rapid and deep and in most cases immediate
    GHG emissions reductions in all sectors. Reductions in GHG emissions in industry,
    transport, buildings, and urban areas can be achieved through a combination of
    energy efficiency and conservation and a transition to low-GHG technologies and
    energy carriers. Socio-cultural options and behavioural change can reduce global
    GHG emissions of end-use sectors, with most of the potential in developed countries,
    if combined with improved infrastructure design and access.  Global modelled mitigation
    pathways reaching net zero CO2 and GHG emissions include transitioning from fossil
    fuels without carbon capture and storage to very low- or zero-carbon energy sources,
    such as renewables or fossil fuels with CCS, demand-side measures and improving
    efficiency, reducing non-CO2 GHG emissions, and CDR 136. In global modelled pathways
    that limit warming to 2°C or below, almost all electricity is supplied from zero
    or low-carbon sources in 2050, such as renewables or fossil fuels with CO2 capture
    and storage, combined with increased electrification of energy demand. Such pathways
    meet energy service demand with relatively low energy use, through e.g., enhanced
    energy efficiency and behavioural changes and increased electrification of energy
    end use. Modelled global pathways limiting global warming to 1.5°C with no or
    limited overshoot generally implement such changes faster than pathways limiting
    global warming to 2°C.  AFOLU mitigation options, when sustainably implemented,
    can deliver large-scale GHG emission reductions and enhanced CO2 removal; however,
    barriers to implementation and trade-offs may result from the impacts of climate
    change, competing demands on land, conflicts with food security and livelihoods,
    the complexity of land ownership and management systems, and cultural aspects.
    All assessed modelled pathways that limit warming to 2°C or lower by 2100 include
    land-based mitigation and land-use change, with most including different combinations
    of reforestation, afforestation, reduced deforestation, and bioenergy. However,
    accumulated carbon in vegetation and soils is at risk from future loss triggered
    by climate change and disturbances such as flood, drought, fire, or pest outbreaks,
    or future poor management.  In addition to deep, rapid, and sustained emission
    reductions, CDR can fulfil three complementary roles: lowering net CO2 or net
    GHG emissions in the near term; counterbalancing ‘hard-to-abate’ residual emissions  to
    help reach net zero CO2 or GHG emissions, and achieving net negative CO 2 or GHG
    emissions if deployed at levels exceeding annual residual emissions. CDR methods
    vary in terms of their maturity, removal process, time scale of carbon storage,
    storage medium, mitigation potential, cost, co-benefits, impacts and risks, and
    governance requirements. Specifically, maturity ranges from lower maturity to
    higher maturity; removal and storage potential ranges from lower potential to
    higher potential; costs range from lower cost to higher cost  . Estimated storage
    timescales vary from decades to centuries for methods that store carbon in vegetation
    and through soil carbon management, to ten thousand years or more for methods
    that store carbon in geological formations . Afforestation, reforestation, improved
    forest management, agroforestry and soil carbon sequestration are currently the
    only widely practiced CDR methods. Methods and levels of CDR deployment in global
    modelled mitigation pathways vary depending on assumptions about costs, availability
    and constraints.'
  B.5.3:
  - The Gap Between Mitigation Policies, Pledges and  Pathways that Limit Warming
    to 1.5°C or Below 2°C Global GHG emissions in 2030 associated with the implementation
    of NDCs announced prior to COP2691 would make it likely that warming will exceed
    1.5°C during the 21st century and would make it harder to limit warming below
    2°C – if no additional commitments are made or actions taken. A substantial ‘emissions
    gap’ exists as global GHG emissions in 2030 associated with the implementation
    of NDCs announced prior to COP26 would be similar to or only slightly below 2019
    emission levels and higher than those associated with modelled mitigation pathways
    that limit warming to 1.5°C with no or limited overshoot or to 2°C, assuming immediate
    action, which implies deep, rapid, and sustained global GHG emission reductions
    this decade  . 92 The magnitude of the emissions gap depends on the global warming
    level considered and whether only unconditional or also conditional elements of
    NDCs 93 are considered . Modelled pathways that are consistent with NDCs announced
    prior to COP26 until 2030 and assume no increase in ambition thereafter have higher
    emissions, leading to a median global warming of 2.8 [2.1 to 3.4]°C by 2100 .
    If the ‘emission gap’ is not reduced, global GHG emissions in 2030 consistent
    with NDCs announced prior to COP26 make it likely that warming will exceed 1.5°C
    during the 21st century, while limiting warming to 2°C would imply an unprecedented
    acceleration of mitigation efforts during 2030–2050 .  Policies implemented by
    the end of 2020 are projected to result in higher global GHG emissions in 2030
    than those implied by NDCs, indicating an ‘implementation gap 94 ’ . Projected
    global emissions implied by policies implemented by the end of 2020 are 57 GtCO2
    -eq in 2030. This points to an implementation gap compared with the NDCs of 4
    to 7 GtCO 2-eq in 2030; without a strengthening of policies, emissions are projected
    to rise, leading to a median global warming of 2.2°C to 3.5°C by 2100 .  Projected
    cumulative future CO2 emissions over the lifetime of existing fossil fuel infrastructure
    without additional abatement exceed the total cumulative net CO2 emissions in
    pathways that limit warming to 1.5°C with no or limited overshoot. They are approximately
    equal to total cumulative net CO2 emissions in pathways that limit warming to
    2°C with a likelihood of 83% 96. Limiting warming to 2°C or lower will result
    in stranded assets. About 80% of coal, 50% of gas, and 30% of oil reserves cannot
    be burned and emitted if warming is limited to 2°C. Significantly more reserves
    are expected to remain unburned if warming is limited to 1.5°C.  Many countries
    have signalled an intention to achieve net zero GHG or net zero CO 2 emissions
    by around mid-century . More than 100 countries have either adopted, announced
    or are discussing net zero GHG or net zero CO 2 emissions commitments, covering
    more than two-thirds of global GHG emissions. A growing number of cities are setting
    climate targets, including net zero GHG targets. Many companies and institutions
    have also announced net zero emissions targets in recent years. The various net
    zero emission pledges differ across countries in terms of scope and specificity,
    and limited policies are to date in place to deliver on them.  All mitigation
    strategies face implementation challenges, including technology risks, scaling,
    and costs. Almost all mitigation options also face institutional barriers that
    need to be addressed to enable their application at scale . Current development
    pathways may create behavioural, spatial, economic and social barriers to accelerated
    mitigation at all scales. Choices made by policymakers, citizens, the private
    sector and other stakeholders influence societies’ development pathways. Structural
    factors of national circumstances and capabilities  affect the breadth and depth
    of climate governance. The extent to which civil society actors, political actors,
    businesses, youth, labour, media, Indigenous Peoples, and local communities are
    engaged influences political support for climate change mitigation and eventual
    policy outcomes.  The adoption of low-emission technologies lags in most developing
    countries, particularly least developed ones, due in part to weaker enabling conditions,
    including limited finance, technology development and transfer, and capacity .
    In many countries, especially those with limited institutional capacity, several
    adverse side-effects have been observed as a result of diffusion of low-emission
    technology, e.g., low-value employment, and dependency on foreign knowledge and
    suppliers. Low-emission innovation along with strengthened enabling conditions
    can reinforce development benefits, which can, in turn, create feedbacks towards
    greater public support for policy. Persistent and region-specific barriers also
    continue to hamper the economic and political feasibility of deploying AFOLU mitigation
    options. Barriers to implementation of AFOLU mitigation include insufficient institutional
    and financial support, uncertainty over long-term additionality and trade-offs,
    weak governance, insecure land ownership, low incomes and the lack of access to
    alternative sources of income, and the risk of reversal .
  - Remaining Carbon Budgets  Limiting global temperature increase to a specific level
    requires limiting cumulative net CO2 emissions to within a finite carbon budget
    , along with strong reductions in other GHGs. For every 1000 GtCO2 emitted by
    human activity, global mean temperature rises by likely 0.27°C to 0.63°C. This
    relationship implies that there is a finite carbon budget that cannot be exceeded
    in order to limit warming to any given level.  The best estimates of the remaining
    carbon budget from the beginning of 2020 for limiting warming to 1.5°C with a
    50% likelihood is estimated to be 500 GtCO2; for 2°C this is 1150 GtCO2.128 Remaining
    carbon budgets have been quantified based on the assessed value of TCRE and its
    uncertainty, estimates of historical warming, climate system feedbacks such as
    emissions from thawing permafrost, and the global surface temperature change after
    global anthropogenic CO 2 emissions reach net zero, as well as variations in projected
    warming from non-CO2 emissions due in part to mitigation action. The stronger
    the reductions in non-CO2 emissions the lower the resulting temperatures are for
    a given RCB or the larger RCB for the same level of temperature change. For instance,
    the RCB for limiting warming to 1.5°C with a 50% likelihood could vary between
    300 to 600 GtCO 2 depending on non-CO 2 warming 129 . Limiting warming to 2°C
    with a 67% likelihood would imply a RCB of 1150 GtCO2 from the beginning of 2020.
    To stay below 2°C with a 50% likelihood, the RCB is higher, i.e., 1350 GtCO 2
    If the annual CO2 emissions between 2020–2030 stayed, on average, at the same
    level as 2019, the resulting cumulative emissions would almost exhaust the remaining
    carbon budget for 1.5°C, and exhaust more than a third of the remaining carbon
    budget for 2°C . Based on central estimates only, historical cumulative net CO2
    emissions between 1850 and 2019 amount to about four-fifths of the total carbon
    budget for a 50% probability of limiting global warming to 1.5°C and to about
    two-thirds of the total carbon budget for a 67% probability to limit global warming
    to 2°C.  In scenarios with increasing CO 2 emissions, the land and ocean carbon
    sinks are projected to be less effective at slowing the accumulation of CO2 in
    the atmosphere. While natural land and ocean carbon sinks are projected to take
    up, in absolute terms, a progressively larger amount of CO 2 under higher compared
    to lower CO2 emissions scenarios, they become less effective, that is, the proportion
    of emissions taken up by land and ocean decreases with increasing cumulative net
    CO2 emissions. Additional ecosystem responses to warming not yet fully included
    in climate models, such as GHG fluxes from wetlands, permafrost thaw, and wildfires,
    would further increase concentrations of these gases in the atmosphere . In scenarios
    where CO2 concentrations peak and decline during the 21st century, the land and
    ocean begin to take up less carbon in response to declining atmospheric CO2 concentrations  and
    turn into a weak net source by 2100 in the very low GHG emissions scenario 133.
  B.6.1:
  - 'Net Zero Emissions: Timing and Implications  From a physical science perspective,
    limiting human-caused global warming to a specific level requires limiting cumulative
    CO2 emissions, reaching net zero or net negative CO2 emissions, along with strong
    reductions of other GHG emissions . Global modelled pathways that reach and sustain
    net zero GHG emissions are projected to result in a gradual decline in surface
    temperature. Reaching net zero GHG emissions primarily requires deep reductions
    in CO2, methane, and other GHG emissions, and implies net negative CO2 emissions.134
    Carbon dioxide removal will be necessary to achieve net negative CO2 emissions
    135. Achieving global net zero CO2 emissions, with remaining anthropogenic CO
    2 emissions balanced by durably stored CO 2 from anthropogenic removal, is a requirement
    to stabilise CO2-induced global surface temperature increase . This is different
    from achieving net zero GHG emissions, where metric-weighted anthropogenic GHG
    emissions  equal CO 2 removal. Emissions pathways that reach and sustain net zero
    GHG emissions defined by the 100-year global warming potential imply net negative
    CO2 emissions and are projected to result in a gradual decline in surface temperature
    after an earlier peak. While reaching net zero CO2 or net zero GHG emissions requires
    deep and rapid reductions in gross emissions, the deployment of CDR to counterbalance
    hardto-abate residual emissions  is unavoidable .  In modelled pathways, the timing
    of net zero CO2 emissions, followed by net zero GHG emissions, depends on several
    variables, including the desired climate outcome, the mitigation strategy and
    the gases covered. Global net zero CO2 emissions are reached in the early 2050s
    in pathways that limit warming to 1.5°C with no or limited overshoot, and around
    the early 2070s in pathways that limit warming to 2°C. While non-CO2 GHG emissions
    are strongly reduced in all pathways that limit warming to 2°C or lower, residual
    emissions of CH4 and N2O and F-gases of about 8 [5–11] GtCO2 -eq yr -1 remain
    at the time of net zero GHG, counterbalanced by net negative CO2 emissions. As
    a result, net zero CO2 would be reached before net zero GHGs .'
  - 'Overshoot Pathways: Increased Risks and Other  Implications Exceeding a specific
    remaining carbon budget results in higher global warming. Achieving and sustaining
    net negative global CO 2 emissions could reverse the resulting temperature exceedance.
    Continued reductions in emissions of short-lived climate forcers, particularly
    methane, after peak temperature has been reached, would also further reduce warming.
    Only a small number of the most ambitious global modelled pathways limit global
    warming to 1.5°C without overshoot.  Overshoot of a warming level results in more
    adverse impacts, some irreversible, and additional risks for human and natural
    systems compared to staying below that warming level, with risks growing with
    the magnitude and duration of overshoot. Compared to pathways without overshoot,
    societies and ecosystems would be exposed to greater and more widespread changes
    in climatic impact-drivers, such as extreme heat and extreme precipitation, with
    increasing risks to infrastructure, low-lying coastal settlements, and associated
    livelihoods. Overshooting 1.5°C will result in irreversible adverse impacts on
    certain ecosystems with low resilience, such as polar, mountain, and coastal ecosystems,
    impacted by ice-sheet melt, glacier melt, or by accelerating and higher committed
    sea level rise. Overshoot increases the risks of severe impacts, such as increased
    wildfires, mass mortality of trees, drying of peatlands, thawing of permafrost
    and weakening natural land carbon sinks; such impacts could increase releases
    of GHGs making temperature reversal more challenging.  The larger the overshoot,
    the more net negative CO2 emissions needed to return to a given warming level.
    Reducing global temperature by removing CO 2 would require net negative emissions
    of 220 GtCO 2 for every tenth of a degree. Modelled pathways that limit warming
    to 1.5°C with no or limited overshoot reach median values of cumulative net negative
    emissions of 220 GtCO2 by 2100, pathways that return warming to 1.5°C after high
    overshoot reach median values of 360 GtCO2. 137 More rapid reduction in CO 2 and
    non-CO2 emissions, particularly methane, limits peak warming levels and reduces
    the requirement for net negative CO2 emissions and CDR, thereby reducing feasibility
    and sustainability concerns, and social and environmental risks .'
  - 'The Timing and Urgency of Climate Action  The magnitude and rate of climate change
    and associated risks depend strongly on near-term mitigation and adaptation actions
    . Global warming is more likely than not to reach 1.5°C between 2021 and 2040
    even under the very low GHG emission scenarios, and likely or very likely to exceed
    1.5°C under higher emissions scenarios 141. Many adaptation options have medium
    or high feasibility up to 1.5°C , but hard limits to adaptation have already been
    reached in some ecosystems and the effectiveness of adaptation to reduce climate
    risk will decrease with increasing warming. Societal choices and actions implemented
    in this decade determine the extent to which medium- and long-term pathways will
    deliver higher or lower climate resilient development. Climate resilient development
    prospects are increasingly limited if current greenhouse gas emissions do not
    rapidly decline, especially if 1.5°C global warming is exceeded in the near term.
    Without urgent, effective and equitable adaptation and mitigation actions, climate
    change increasingly threatens the health and livelihoods of people around the
    globe, ecosystem health, and biodiversity, with severe adverse consequences for
    current and future generations. .  In modelled pathways that limit warming to
    1.5°C with no or limited overshoot and in those that limit warming to 2°C, assuming
    immediate actions, global GHG emissions are projected to peak in the early 2020s
    followed by rapid and deep GHG emissions reductions 142 . In pathways that limit
    warming to 1.5°C with no or limited overshoot, net global GHG emissions are projected
    to fall by 43 [34 to 60]%143 below 2019 levels by 2030, 60 [49 to 77]% by 2035,
    69 [58 to 90]% by 2040 and 84 [73 to 98]% by 2050 144. Global modelled pathways
    that limit warming to 2°C have reductions in GHG emissions below 2019 levels of
    21 [1 to 42]% by 2030, 35 [22 to 55] % by 2035, 46 [34 to 63] % by 2040 and 64
    [53 to 77]% by 2050145. Global GHG emissions associated with NDCs announced prior
    to COP26 would make it likely that warming would exceed 1.5°C and limiting warming
    to 2°C would then imply a rapid acceleration of emission reductions during 2030–2050,
    around 70% faster than in pathways where immediate action is taken to limit warming
    to 2°C Continued investments in unabated high-emitting infrastructure and limited
    development and deployment of low-emitting alternatives prior to 2030 would act
    as barriers to this acceleration and increase feasibility risks.  All global modelled
    pathways that limit warming to 2°C or lower by 2100 involve reductions in both
    net CO 2 emissions and non-CO 2 emissions. For example, in pathways that limit
    warming to 1.5°C with no or limited overshoot, global CH4 emissions are reduced
    by 34 [21 to 57]% below 2019 levels by 2030 and by 44 [31 to 63]% in 2040. Global
    CH 4 emissions are reduced by 24 [9 to 53]% below 2019 levels by 2030 and by 37
    [20 to 60]% in 2040 in modelled pathways that limit warming to 2°C with action
    starting in 2020.  All global modelled pathways that limit warming to 2°C or lower
    by 2100 involve GHG emission reductions in all sectors . The contributions of
    different sectors vary across modelled mitigation pathways. In most global modelled
    mitigation pathways, emissions from land-use, land-use change and forestry, via
    reforestation and reduced deforestation, and from the energy supply sector reach
    net zero CO2 emissions earlier than the buildings, industry and transport sectors.
    Strategies can rely on combinations of different options, but doing less in one
    sector needs to be compensated by further reductions in other sectors if warming
    is to be limited.  Without rapid, deep and sustained mitigation and accelerated
    adaptation actions, losses and damages will continue to increase, including projected
    adverse impacts in Africa, LDCs, SIDS, Central and South America , Asia and the
    Arctic, and will disproportionately affect the most vulnerable populations .  '
  B.6.2:
  - 'Net Zero Emissions: Timing and Implications  From a physical science perspective,
    limiting human-caused global warming to a specific level requires limiting cumulative
    CO2 emissions, reaching net zero or net negative CO2 emissions, along with strong
    reductions of other GHG emissions . Global modelled pathways that reach and sustain
    net zero GHG emissions are projected to result in a gradual decline in surface
    temperature. Reaching net zero GHG emissions primarily requires deep reductions
    in CO2, methane, and other GHG emissions, and implies net negative CO2 emissions.134
    Carbon dioxide removal will be necessary to achieve net negative CO2 emissions
    135. Achieving global net zero CO2 emissions, with remaining anthropogenic CO
    2 emissions balanced by durably stored CO 2 from anthropogenic removal, is a requirement
    to stabilise CO2-induced global surface temperature increase . This is different
    from achieving net zero GHG emissions, where metric-weighted anthropogenic GHG
    emissions  equal CO 2 removal. Emissions pathways that reach and sustain net zero
    GHG emissions defined by the 100-year global warming potential imply net negative
    CO2 emissions and are projected to result in a gradual decline in surface temperature
    after an earlier peak. While reaching net zero CO2 or net zero GHG emissions requires
    deep and rapid reductions in gross emissions, the deployment of CDR to counterbalance
    hardto-abate residual emissions  is unavoidable .  In modelled pathways, the timing
    of net zero CO2 emissions, followed by net zero GHG emissions, depends on several
    variables, including the desired climate outcome, the mitigation strategy and
    the gases covered. Global net zero CO2 emissions are reached in the early 2050s
    in pathways that limit warming to 1.5°C with no or limited overshoot, and around
    the early 2070s in pathways that limit warming to 2°C. While non-CO2 GHG emissions
    are strongly reduced in all pathways that limit warming to 2°C or lower, residual
    emissions of CH4 and N2O and F-gases of about 8 [5–11] GtCO2 -eq yr -1 remain
    at the time of net zero GHG, counterbalanced by net negative CO2 emissions. As
    a result, net zero CO2 would be reached before net zero GHGs .'
  - 'Sectoral Contributions to Mitigation  All global modelled pathways that limit
    warming to 2°C or lower by 2100 involve rapid and deep and in most cases immediate
    GHG emissions reductions in all sectors. Reductions in GHG emissions in industry,
    transport, buildings, and urban areas can be achieved through a combination of
    energy efficiency and conservation and a transition to low-GHG technologies and
    energy carriers. Socio-cultural options and behavioural change can reduce global
    GHG emissions of end-use sectors, with most of the potential in developed countries,
    if combined with improved infrastructure design and access.  Global modelled mitigation
    pathways reaching net zero CO2 and GHG emissions include transitioning from fossil
    fuels without carbon capture and storage to very low- or zero-carbon energy sources,
    such as renewables or fossil fuels with CCS, demand-side measures and improving
    efficiency, reducing non-CO2 GHG emissions, and CDR 136. In global modelled pathways
    that limit warming to 2°C or below, almost all electricity is supplied from zero
    or low-carbon sources in 2050, such as renewables or fossil fuels with CO2 capture
    and storage, combined with increased electrification of energy demand. Such pathways
    meet energy service demand with relatively low energy use, through e.g., enhanced
    energy efficiency and behavioural changes and increased electrification of energy
    end use. Modelled global pathways limiting global warming to 1.5°C with no or
    limited overshoot generally implement such changes faster than pathways limiting
    global warming to 2°C.  AFOLU mitigation options, when sustainably implemented,
    can deliver large-scale GHG emission reductions and enhanced CO2 removal; however,
    barriers to implementation and trade-offs may result from the impacts of climate
    change, competing demands on land, conflicts with food security and livelihoods,
    the complexity of land ownership and management systems, and cultural aspects.
    All assessed modelled pathways that limit warming to 2°C or lower by 2100 include
    land-based mitigation and land-use change, with most including different combinations
    of reforestation, afforestation, reduced deforestation, and bioenergy. However,
    accumulated carbon in vegetation and soils is at risk from future loss triggered
    by climate change and disturbances such as flood, drought, fire, or pest outbreaks,
    or future poor management.  In addition to deep, rapid, and sustained emission
    reductions, CDR can fulfil three complementary roles: lowering net CO2 or net
    GHG emissions in the near term; counterbalancing ‘hard-to-abate’ residual emissions  to
    help reach net zero CO2 or GHG emissions, and achieving net negative CO 2 or GHG
    emissions if deployed at levels exceeding annual residual emissions. CDR methods
    vary in terms of their maturity, removal process, time scale of carbon storage,
    storage medium, mitigation potential, cost, co-benefits, impacts and risks, and
    governance requirements. Specifically, maturity ranges from lower maturity to
    higher maturity; removal and storage potential ranges from lower potential to
    higher potential; costs range from lower cost to higher cost  . Estimated storage
    timescales vary from decades to centuries for methods that store carbon in vegetation
    and through soil carbon management, to ten thousand years or more for methods
    that store carbon in geological formations . Afforestation, reforestation, improved
    forest management, agroforestry and soil carbon sequestration are currently the
    only widely practiced CDR methods. Methods and levels of CDR deployment in global
    modelled mitigation pathways vary depending on assumptions about costs, availability
    and constraints.'
  B.6.3:
  - 'Sectoral Contributions to Mitigation  All global modelled pathways that limit
    warming to 2°C or lower by 2100 involve rapid and deep and in most cases immediate
    GHG emissions reductions in all sectors. Reductions in GHG emissions in industry,
    transport, buildings, and urban areas can be achieved through a combination of
    energy efficiency and conservation and a transition to low-GHG technologies and
    energy carriers. Socio-cultural options and behavioural change can reduce global
    GHG emissions of end-use sectors, with most of the potential in developed countries,
    if combined with improved infrastructure design and access.  Global modelled mitigation
    pathways reaching net zero CO2 and GHG emissions include transitioning from fossil
    fuels without carbon capture and storage to very low- or zero-carbon energy sources,
    such as renewables or fossil fuels with CCS, demand-side measures and improving
    efficiency, reducing non-CO2 GHG emissions, and CDR 136. In global modelled pathways
    that limit warming to 2°C or below, almost all electricity is supplied from zero
    or low-carbon sources in 2050, such as renewables or fossil fuels with CO2 capture
    and storage, combined with increased electrification of energy demand. Such pathways
    meet energy service demand with relatively low energy use, through e.g., enhanced
    energy efficiency and behavioural changes and increased electrification of energy
    end use. Modelled global pathways limiting global warming to 1.5°C with no or
    limited overshoot generally implement such changes faster than pathways limiting
    global warming to 2°C.  AFOLU mitigation options, when sustainably implemented,
    can deliver large-scale GHG emission reductions and enhanced CO2 removal; however,
    barriers to implementation and trade-offs may result from the impacts of climate
    change, competing demands on land, conflicts with food security and livelihoods,
    the complexity of land ownership and management systems, and cultural aspects.
    All assessed modelled pathways that limit warming to 2°C or lower by 2100 include
    land-based mitigation and land-use change, with most including different combinations
    of reforestation, afforestation, reduced deforestation, and bioenergy. However,
    accumulated carbon in vegetation and soils is at risk from future loss triggered
    by climate change and disturbances such as flood, drought, fire, or pest outbreaks,
    or future poor management.  In addition to deep, rapid, and sustained emission
    reductions, CDR can fulfil three complementary roles: lowering net CO2 or net
    GHG emissions in the near term; counterbalancing ‘hard-to-abate’ residual emissions  to
    help reach net zero CO2 or GHG emissions, and achieving net negative CO 2 or GHG
    emissions if deployed at levels exceeding annual residual emissions. CDR methods
    vary in terms of their maturity, removal process, time scale of carbon storage,
    storage medium, mitigation potential, cost, co-benefits, impacts and risks, and
    governance requirements. Specifically, maturity ranges from lower maturity to
    higher maturity; removal and storage potential ranges from lower potential to
    higher potential; costs range from lower cost to higher cost  . Estimated storage
    timescales vary from decades to centuries for methods that store carbon in vegetation
    and through soil carbon management, to ten thousand years or more for methods
    that store carbon in geological formations . Afforestation, reforestation, improved
    forest management, agroforestry and soil carbon sequestration are currently the
    only widely practiced CDR methods. Methods and levels of CDR deployment in global
    modelled mitigation pathways vary depending on assumptions about costs, availability
    and constraints.'
  - 'The Timing and Urgency of Climate Action  The magnitude and rate of climate change
    and associated risks depend strongly on near-term mitigation and adaptation actions
    . Global warming is more likely than not to reach 1.5°C between 2021 and 2040
    even under the very low GHG emission scenarios, and likely or very likely to exceed
    1.5°C under higher emissions scenarios 141. Many adaptation options have medium
    or high feasibility up to 1.5°C , but hard limits to adaptation have already been
    reached in some ecosystems and the effectiveness of adaptation to reduce climate
    risk will decrease with increasing warming. Societal choices and actions implemented
    in this decade determine the extent to which medium- and long-term pathways will
    deliver higher or lower climate resilient development. Climate resilient development
    prospects are increasingly limited if current greenhouse gas emissions do not
    rapidly decline, especially if 1.5°C global warming is exceeded in the near term.
    Without urgent, effective and equitable adaptation and mitigation actions, climate
    change increasingly threatens the health and livelihoods of people around the
    globe, ecosystem health, and biodiversity, with severe adverse consequences for
    current and future generations. .  In modelled pathways that limit warming to
    1.5°C with no or limited overshoot and in those that limit warming to 2°C, assuming
    immediate actions, global GHG emissions are projected to peak in the early 2020s
    followed by rapid and deep GHG emissions reductions 142 . In pathways that limit
    warming to 1.5°C with no or limited overshoot, net global GHG emissions are projected
    to fall by 43 [34 to 60]%143 below 2019 levels by 2030, 60 [49 to 77]% by 2035,
    69 [58 to 90]% by 2040 and 84 [73 to 98]% by 2050 144. Global modelled pathways
    that limit warming to 2°C have reductions in GHG emissions below 2019 levels of
    21 [1 to 42]% by 2030, 35 [22 to 55] % by 2035, 46 [34 to 63] % by 2040 and 64
    [53 to 77]% by 2050145. Global GHG emissions associated with NDCs announced prior
    to COP26 would make it likely that warming would exceed 1.5°C and limiting warming
    to 2°C would then imply a rapid acceleration of emission reductions during 2030–2050,
    around 70% faster than in pathways where immediate action is taken to limit warming
    to 2°C Continued investments in unabated high-emitting infrastructure and limited
    development and deployment of low-emitting alternatives prior to 2030 would act
    as barriers to this acceleration and increase feasibility risks.  All global modelled
    pathways that limit warming to 2°C or lower by 2100 involve reductions in both
    net CO 2 emissions and non-CO 2 emissions. For example, in pathways that limit
    warming to 1.5°C with no or limited overshoot, global CH4 emissions are reduced
    by 34 [21 to 57]% below 2019 levels by 2030 and by 44 [31 to 63]% in 2040. Global
    CH 4 emissions are reduced by 24 [9 to 53]% below 2019 levels by 2030 and by 37
    [20 to 60]% in 2040 in modelled pathways that limit warming to 2°C with action
    starting in 2020.  All global modelled pathways that limit warming to 2°C or lower
    by 2100 involve GHG emission reductions in all sectors . The contributions of
    different sectors vary across modelled mitigation pathways. In most global modelled
    mitigation pathways, emissions from land-use, land-use change and forestry, via
    reforestation and reduced deforestation, and from the energy supply sector reach
    net zero CO2 emissions earlier than the buildings, industry and transport sectors.
    Strategies can rely on combinations of different options, but doing less in one
    sector needs to be compensated by further reductions in other sectors if warming
    is to be limited.  Without rapid, deep and sustained mitigation and accelerated
    adaptation actions, losses and damages will continue to increase, including projected
    adverse impacts in Africa, LDCs, SIDS, Central and South America , Asia and the
    Arctic, and will disproportionately affect the most vulnerable populations .  '
  - Near-Term Mitigation and Adaptation Actions  Rapid and far-reaching transitions
    across all sectors and systems are necessary to achieve deep and sustained emissions
    reductions and secure a liveable and sustainable future for all. These system
    transitions involve a significant upscaling of a wide portfolio of mitigation
    and adaptation options. Feasible, effective and low-cost options for mitigation
    and adaptation are already available, with differences across systems and regions.  Rapid
    and far-reaching transitions across all sectors and systems are necessary to achieve
    deep emissions reductions and secure a liveable and sustainable future for all.
    System transitions consistent with pathways that limit warming to 1.5°C with no
    or limited overshoot are more rapid and pronounced in the near-term than in those
    that limit warming to 2°C . Such a systemic change is unprecedented in terms of
    scale, but not necessarily in terms of speed. The system transitions make possible
    the transformative adaptation required for high levels of human health and well-being,
    economic and social resilience, ecosystem health, and planetary health.  Feasible,
    effective and low-cost options for mitigation and adaptation are already available.
    Mitigation options costing USD 100 tCO 2-eq–1 or less could reduce global GHG
    emissions by at least half the 2019 level by 2030  . The availability, feasibility
    152 and potential of mitigation or effectiveness of adaptation options in the
    near term differ across systems and regions.  Demand-side measures and new ways
    of end-use service provision can reduce global GHG emissions in end-use sectors
    by 40 to 70% by 2050 compared to baseline scenarios, while some regions and socioeconomic
    groups require additional energy and resources. Demand-side mitigation encompasses
    changes in infrastructure use, end-use technology adoption, and socio-cultural
    and behavioural change. .
  B.6.4:
  - Synergies and trade-offs, costs and benefits  Mitigation and adaptation options
    can lead to synergies and trade-offs with other aspects of sustainable development
    . Synergies and trade-offs depend on the pace and magnitude of changes and the
    development context including inequalities, with consideration of climate justice.
    The potential or effectiveness of some adaptation and mitigation options decreases
    as climate change intensifies .  In the energy sector, transitions to low-emission
    systems will have multiple co-benefits, including improvements in air quality
    and health. There are potential synergies between sustainable development and,
    for instance, energy efficiency and renewable energy.  For agriculture, land,
    and food systems, many land management options and demand-side response options  can
    contribute to eradicating poverty and eliminating hunger while promoting good
    health and well-being, clean water and sanitation, and life on land . In contrast,
    certain adaptation options that promote intensification of production, such as
    irrigation, may have negative effects on sustainability  .  Reforestation, improved
    forest management, soil carbon sequestration, peatland restoration and coastal
    blue carbon management are examples of CDR methods that can enhance biodiversity
    and ecosystem functions, employment and local livelihoods, depending on context
    . However, afforestation or production of biomass crops for bioenergy with carbon
    dioxide capture and storage or biochar can have adverse socio-economic and environmental
    impacts, including on biodiversity, food and water security, local livelihoods
    and the rights of Indigenous Peoples, especially if implemented at large scales
    and where land tenure is insecure.  Modelled pathways that assume using resources
    more efficiently or shift global development towards sustainability include fewer
    challenges, such as dependence on CDR and pressure on land and biodiversity, and
    have the most pronounced synergies with respect to sustainable development .  Strengthening
    climate change mitigation action entails more rapid transitions and higher up-front
    investments, but brings benefits from avoiding damages from climate change and
    reduced adaptation costs. The aggregate effects of climate change mitigation on
    global GDP  are small compared to global projected GDP growth. Projected estimates
    of global aggregate net economic damages and the costs of adaptation generally
    increase with global warming level.  Cost-benefit analysis remains limited in
    its ability to represent all damages from climate change, including non-monetary
    damages, or to capture the heterogeneous nature of damages and the risk of catastrophic
    damages. Even without accounting for these factors or for the co-benefits of mitigation,
    the global benefits of limiting warming to 2°C exceed the cost of mitigation .
    This finding is robust against a wide range of assumptions about social preferences
    on inequalities and discounting over time . Limiting global warming to 1.5°C instead
    of 2°C would increase the costs of mitigation, but also increase the benefits
    in terms of reduced impacts and related risks and reduced adaptation needs 140.  Considering
    other sustainable development dimensions, such as the potentially strong economic
    benefits on human health from air quality improvement, may enhance the estimated
    benefits of mitigation . The economic effects of strengthened mitigation action
    vary across regions and countries, depending notably on economic structure, regional
    emissions reductions, policy design and level of international cooperation. Ambitious
    mitigation pathways imply large and sometimes disruptive changes in economic structure,
    with implications for near-term actions, equity , sustainability, and finance
    .
  B.7.1:
  - 'Net Zero Emissions: Timing and Implications  From a physical science perspective,
    limiting human-caused global warming to a specific level requires limiting cumulative
    CO2 emissions, reaching net zero or net negative CO2 emissions, along with strong
    reductions of other GHG emissions . Global modelled pathways that reach and sustain
    net zero GHG emissions are projected to result in a gradual decline in surface
    temperature. Reaching net zero GHG emissions primarily requires deep reductions
    in CO2, methane, and other GHG emissions, and implies net negative CO2 emissions.134
    Carbon dioxide removal will be necessary to achieve net negative CO2 emissions
    135. Achieving global net zero CO2 emissions, with remaining anthropogenic CO
    2 emissions balanced by durably stored CO 2 from anthropogenic removal, is a requirement
    to stabilise CO2-induced global surface temperature increase . This is different
    from achieving net zero GHG emissions, where metric-weighted anthropogenic GHG
    emissions  equal CO 2 removal. Emissions pathways that reach and sustain net zero
    GHG emissions defined by the 100-year global warming potential imply net negative
    CO2 emissions and are projected to result in a gradual decline in surface temperature
    after an earlier peak. While reaching net zero CO2 or net zero GHG emissions requires
    deep and rapid reductions in gross emissions, the deployment of CDR to counterbalance
    hardto-abate residual emissions  is unavoidable .  In modelled pathways, the timing
    of net zero CO2 emissions, followed by net zero GHG emissions, depends on several
    variables, including the desired climate outcome, the mitigation strategy and
    the gases covered. Global net zero CO2 emissions are reached in the early 2050s
    in pathways that limit warming to 1.5°C with no or limited overshoot, and around
    the early 2070s in pathways that limit warming to 2°C. While non-CO2 GHG emissions
    are strongly reduced in all pathways that limit warming to 2°C or lower, residual
    emissions of CH4 and N2O and F-gases of about 8 [5–11] GtCO2 -eq yr -1 remain
    at the time of net zero GHG, counterbalanced by net negative CO2 emissions. As
    a result, net zero CO2 would be reached before net zero GHGs .'
  - 'Overshoot Pathways: Increased Risks and Other  Implications Exceeding a specific
    remaining carbon budget results in higher global warming. Achieving and sustaining
    net negative global CO 2 emissions could reverse the resulting temperature exceedance.
    Continued reductions in emissions of short-lived climate forcers, particularly
    methane, after peak temperature has been reached, would also further reduce warming.
    Only a small number of the most ambitious global modelled pathways limit global
    warming to 1.5°C without overshoot.  Overshoot of a warming level results in more
    adverse impacts, some irreversible, and additional risks for human and natural
    systems compared to staying below that warming level, with risks growing with
    the magnitude and duration of overshoot. Compared to pathways without overshoot,
    societies and ecosystems would be exposed to greater and more widespread changes
    in climatic impact-drivers, such as extreme heat and extreme precipitation, with
    increasing risks to infrastructure, low-lying coastal settlements, and associated
    livelihoods. Overshooting 1.5°C will result in irreversible adverse impacts on
    certain ecosystems with low resilience, such as polar, mountain, and coastal ecosystems,
    impacted by ice-sheet melt, glacier melt, or by accelerating and higher committed
    sea level rise. Overshoot increases the risks of severe impacts, such as increased
    wildfires, mass mortality of trees, drying of peatlands, thawing of permafrost
    and weakening natural land carbon sinks; such impacts could increase releases
    of GHGs making temperature reversal more challenging.  The larger the overshoot,
    the more net negative CO2 emissions needed to return to a given warming level.
    Reducing global temperature by removing CO 2 would require net negative emissions
    of 220 GtCO 2 for every tenth of a degree. Modelled pathways that limit warming
    to 1.5°C with no or limited overshoot reach median values of cumulative net negative
    emissions of 220 GtCO2 by 2100, pathways that return warming to 1.5°C after high
    overshoot reach median values of 360 GtCO2. 137 More rapid reduction in CO 2 and
    non-CO2 emissions, particularly methane, limits peak warming levels and reduces
    the requirement for net negative CO2 emissions and CDR, thereby reducing feasibility
    and sustainability concerns, and social and environmental risks .'
  B.7.2:
  - Impacts and Related Risks  For a given level of warming, many climate-related
    risks are assessed to be higher than in AR5. Levels of risk for all Reasons for
    Concern 121 are assessed to become high to very high at lower global warming levels
    compared to what was assessed in AR5. This is based upon recent evidence of observed
    impacts, improved process understanding, and new knowledge on exposure and vulnerability
    of human and natural systems, including limits to adaptation. Depending on the
    level of global warming, the assessed long-term impacts will be up to multiple
    times higher than currently observed for 127 identified key risks, e.g., in terms
    of the number of affected people and species. Risks, including cascading risks
    and risks from overshoot, are projected to become increasingly severe with every
    increment of global warming.  Climate-related risks for natural and human systems
    are higher for global warming of 1.5°C than at present but lower than at 2°C .
    Climate-related risks to health, livelihoods, food security, water supply, human
    security, and economic growth are projected to increase with global warming of
    1.5°C. In terrestrial ecosystems, 3 to 14% of the tens of thousands of species
    assessed will likely face a very high risk of extinction at a GWL of 1.5°C. Coral
    reefs are projected to decline by a further 70–90% at 1.5°C of global warming.
    At this GWL, many low-elevation and small glaciers around the world would lose
    most of their mass or disappear within decades to centuries. Regions at disproportionately
    higher risk include Arctic ecosystems, dryland regions, small island developing
    states and Least Developed Countries .  At 2°C of global warming, overall risk
    levels associated with the unequal distribution of impacts, global aggregate impacts
    and large-scale singular events would be transitioning to high , those associated
    with extreme weather events would be transitioning to very high, and those associated
    with unique and threatened systems would be very high  . With about 2°C warming,
    climate-related changes in food availability and diet quality are estimated to
    increase nutrition-related diseases and the number of undernourished people, affecting
    tens to hundreds of millions of people, particularly among low-income households
    in low- and middle-income countries in sub-Saharan Africa, South Asia and Central
    America. For example, snowmelt water availability for irrigation is projected
    to decline in some snowmelt dependent river basins by up to 20% . Climate change
    risks to cities, settlements and key infrastructure will rise sharply in the mid
    and long term with further global warming, especially in places already exposed
    to high temperatures, along coastlines, or with high vulnerabilities .  At global
    warming of 3°C, additional risks in many sectors and regions reach high or very
    high levels, implying widespread systemic impacts, irreversible change and many
    additional adaptation limits . For example, very high extinction risk for endemic
    species in biodiversity hotspots is projected to increase at least tenfold if
    warming rises from 1.5°C to 3°C. Projected increases in direct flood damages are
    higher by 1.4 to 2 times at 2°C and 2.5 to 3.9 times at 3°C, compared to 1.5°C
    global warming without adaptation.  Global warming of 4°C and above is projected
    to lead to far-reaching impacts on natural and human systems. Beyond 4°C of warming,
    projected impacts on natural systems include local extinction of ~50% of tropical
    marine species and biome shifts across 35% of global land area. At this level
    of warming, approximately 10% of the global land area is projected to face both
    increasing high and decreasing low extreme streamflow, affecting, without additional
    adaptation, over 2.1 billion people and about 4 billion people are projected to
    experience water scarcity. At 4°C of warming, the global burned area is projected
    to increase by 50 to 70% and the fire frequency by ~30% compared to today.  Projected
    adverse impacts and related losses and damages from climate change escalate with
    every increment of global warming , but they will also strongly depend on socio-economic
    development trajectories and adaptation actions to reduce vulnerability and exposure.
    For example, development pathways with higher demand for food, animal feed, and
    water, more resource-intensive consumption and production, and limited technological
    improvements result in higher risks from water scarcity in drylands, land degradation
    and food insecurity . Changes in, for example, demography or investments in health
    systems have effect on a variety of health-related outcomes including heat-related
    morbidity and mortality.  With every increment of warming, climate change impacts
    and risks will become increasingly complex and more difficult to manage. Many
    regions are projected to experience an increase in the probability of compound
    events with higher global warming, such as concurrent heatwaves and droughts,
    compound flooding and fire weather. In addition, multiple climatic and non-climatic
    risk drivers such as biodiversity loss or violent conflict will interact, resulting
    in compounding overall risk and risks cascading across sectors and regions. Furthermore,
    risks can arise from some responses that are intended to reduce the risks of climate
    change, e.g., adverse side effects of some emission reduction and carbon dioxide
    removal measures .  Solar Radiation Modification approaches, if they were to be
    implemented, introduce a widespread range of new risks to people and ecosystems,
    which are not well understood. SRM has the potential to offset warming within
    one or two decades and ameliorate some climate hazards but would not restore climate
    to a previous state, and substantial residual or overcompensating climate change
    would occur at regional and seasonal scales. Effects of SRM would depend on the
    specific approach used 122, and a sudden and sustained termination of SRM in a
    high CO 2 emissions scenario would cause rapid climate change. SRM would not stop
    atmospheric CO 2 concentrations from increasing nor reduce resulting ocean acidification
    under continued anthropogenic emissions. Large uncertainties and knowledge gaps
    are associated with the potential of SRM approaches to reduce climate change risks.
    Lack of robust and formal SRM governance poses risks as deployment by a limited
    number of states could create international tensions.
  - 'Overshoot Pathways: Increased Risks and Other  Implications Exceeding a specific
    remaining carbon budget results in higher global warming. Achieving and sustaining
    net negative global CO 2 emissions could reverse the resulting temperature exceedance.
    Continued reductions in emissions of short-lived climate forcers, particularly
    methane, after peak temperature has been reached, would also further reduce warming.
    Only a small number of the most ambitious global modelled pathways limit global
    warming to 1.5°C without overshoot.  Overshoot of a warming level results in more
    adverse impacts, some irreversible, and additional risks for human and natural
    systems compared to staying below that warming level, with risks growing with
    the magnitude and duration of overshoot. Compared to pathways without overshoot,
    societies and ecosystems would be exposed to greater and more widespread changes
    in climatic impact-drivers, such as extreme heat and extreme precipitation, with
    increasing risks to infrastructure, low-lying coastal settlements, and associated
    livelihoods. Overshooting 1.5°C will result in irreversible adverse impacts on
    certain ecosystems with low resilience, such as polar, mountain, and coastal ecosystems,
    impacted by ice-sheet melt, glacier melt, or by accelerating and higher committed
    sea level rise. Overshoot increases the risks of severe impacts, such as increased
    wildfires, mass mortality of trees, drying of peatlands, thawing of permafrost
    and weakening natural land carbon sinks; such impacts could increase releases
    of GHGs making temperature reversal more challenging.  The larger the overshoot,
    the more net negative CO2 emissions needed to return to a given warming level.
    Reducing global temperature by removing CO 2 would require net negative emissions
    of 220 GtCO 2 for every tenth of a degree. Modelled pathways that limit warming
    to 1.5°C with no or limited overshoot reach median values of cumulative net negative
    emissions of 220 GtCO2 by 2100, pathways that return warming to 1.5°C after high
    overshoot reach median values of 360 GtCO2. 137 More rapid reduction in CO 2 and
    non-CO2 emissions, particularly methane, limits peak warming levels and reduces
    the requirement for net negative CO2 emissions and CDR, thereby reducing feasibility
    and sustainability concerns, and social and environmental risks .'
  B.7.3:
  - 'Sectoral Contributions to Mitigation  All global modelled pathways that limit
    warming to 2°C or lower by 2100 involve rapid and deep and in most cases immediate
    GHG emissions reductions in all sectors. Reductions in GHG emissions in industry,
    transport, buildings, and urban areas can be achieved through a combination of
    energy efficiency and conservation and a transition to low-GHG technologies and
    energy carriers. Socio-cultural options and behavioural change can reduce global
    GHG emissions of end-use sectors, with most of the potential in developed countries,
    if combined with improved infrastructure design and access.  Global modelled mitigation
    pathways reaching net zero CO2 and GHG emissions include transitioning from fossil
    fuels without carbon capture and storage to very low- or zero-carbon energy sources,
    such as renewables or fossil fuels with CCS, demand-side measures and improving
    efficiency, reducing non-CO2 GHG emissions, and CDR 136. In global modelled pathways
    that limit warming to 2°C or below, almost all electricity is supplied from zero
    or low-carbon sources in 2050, such as renewables or fossil fuels with CO2 capture
    and storage, combined with increased electrification of energy demand. Such pathways
    meet energy service demand with relatively low energy use, through e.g., enhanced
    energy efficiency and behavioural changes and increased electrification of energy
    end use. Modelled global pathways limiting global warming to 1.5°C with no or
    limited overshoot generally implement such changes faster than pathways limiting
    global warming to 2°C.  AFOLU mitigation options, when sustainably implemented,
    can deliver large-scale GHG emission reductions and enhanced CO2 removal; however,
    barriers to implementation and trade-offs may result from the impacts of climate
    change, competing demands on land, conflicts with food security and livelihoods,
    the complexity of land ownership and management systems, and cultural aspects.
    All assessed modelled pathways that limit warming to 2°C or lower by 2100 include
    land-based mitigation and land-use change, with most including different combinations
    of reforestation, afforestation, reduced deforestation, and bioenergy. However,
    accumulated carbon in vegetation and soils is at risk from future loss triggered
    by climate change and disturbances such as flood, drought, fire, or pest outbreaks,
    or future poor management.  In addition to deep, rapid, and sustained emission
    reductions, CDR can fulfil three complementary roles: lowering net CO2 or net
    GHG emissions in the near term; counterbalancing ‘hard-to-abate’ residual emissions  to
    help reach net zero CO2 or GHG emissions, and achieving net negative CO 2 or GHG
    emissions if deployed at levels exceeding annual residual emissions. CDR methods
    vary in terms of their maturity, removal process, time scale of carbon storage,
    storage medium, mitigation potential, cost, co-benefits, impacts and risks, and
    governance requirements. Specifically, maturity ranges from lower maturity to
    higher maturity; removal and storage potential ranges from lower potential to
    higher potential; costs range from lower cost to higher cost  . Estimated storage
    timescales vary from decades to centuries for methods that store carbon in vegetation
    and through soil carbon management, to ten thousand years or more for methods
    that store carbon in geological formations . Afforestation, reforestation, improved
    forest management, agroforestry and soil carbon sequestration are currently the
    only widely practiced CDR methods. Methods and levels of CDR deployment in global
    modelled mitigation pathways vary depending on assumptions about costs, availability
    and constraints.'
  - 'Overshoot Pathways: Increased Risks and Other  Implications Exceeding a specific
    remaining carbon budget results in higher global warming. Achieving and sustaining
    net negative global CO 2 emissions could reverse the resulting temperature exceedance.
    Continued reductions in emissions of short-lived climate forcers, particularly
    methane, after peak temperature has been reached, would also further reduce warming.
    Only a small number of the most ambitious global modelled pathways limit global
    warming to 1.5°C without overshoot.  Overshoot of a warming level results in more
    adverse impacts, some irreversible, and additional risks for human and natural
    systems compared to staying below that warming level, with risks growing with
    the magnitude and duration of overshoot. Compared to pathways without overshoot,
    societies and ecosystems would be exposed to greater and more widespread changes
    in climatic impact-drivers, such as extreme heat and extreme precipitation, with
    increasing risks to infrastructure, low-lying coastal settlements, and associated
    livelihoods. Overshooting 1.5°C will result in irreversible adverse impacts on
    certain ecosystems with low resilience, such as polar, mountain, and coastal ecosystems,
    impacted by ice-sheet melt, glacier melt, or by accelerating and higher committed
    sea level rise. Overshoot increases the risks of severe impacts, such as increased
    wildfires, mass mortality of trees, drying of peatlands, thawing of permafrost
    and weakening natural land carbon sinks; such impacts could increase releases
    of GHGs making temperature reversal more challenging.  The larger the overshoot,
    the more net negative CO2 emissions needed to return to a given warming level.
    Reducing global temperature by removing CO 2 would require net negative emissions
    of 220 GtCO 2 for every tenth of a degree. Modelled pathways that limit warming
    to 1.5°C with no or limited overshoot reach median values of cumulative net negative
    emissions of 220 GtCO2 by 2100, pathways that return warming to 1.5°C after high
    overshoot reach median values of 360 GtCO2. 137 More rapid reduction in CO 2 and
    non-CO2 emissions, particularly methane, limits peak warming levels and reduces
    the requirement for net negative CO2 emissions and CDR, thereby reducing feasibility
    and sustainability concerns, and social and environmental risks .'
  - Synergies and trade-offs, costs and benefits  Mitigation and adaptation options
    can lead to synergies and trade-offs with other aspects of sustainable development
    . Synergies and trade-offs depend on the pace and magnitude of changes and the
    development context including inequalities, with consideration of climate justice.
    The potential or effectiveness of some adaptation and mitigation options decreases
    as climate change intensifies .  In the energy sector, transitions to low-emission
    systems will have multiple co-benefits, including improvements in air quality
    and health. There are potential synergies between sustainable development and,
    for instance, energy efficiency and renewable energy.  For agriculture, land,
    and food systems, many land management options and demand-side response options  can
    contribute to eradicating poverty and eliminating hunger while promoting good
    health and well-being, clean water and sanitation, and life on land . In contrast,
    certain adaptation options that promote intensification of production, such as
    irrigation, may have negative effects on sustainability  .  Reforestation, improved
    forest management, soil carbon sequestration, peatland restoration and coastal
    blue carbon management are examples of CDR methods that can enhance biodiversity
    and ecosystem functions, employment and local livelihoods, depending on context
    . However, afforestation or production of biomass crops for bioenergy with carbon
    dioxide capture and storage or biochar can have adverse socio-economic and environmental
    impacts, including on biodiversity, food and water security, local livelihoods
    and the rights of Indigenous Peoples, especially if implemented at large scales
    and where land tenure is insecure.  Modelled pathways that assume using resources
    more efficiently or shift global development towards sustainability include fewer
    challenges, such as dependence on CDR and pressure on land and biodiversity, and
    have the most pronounced synergies with respect to sustainable development .  Strengthening
    climate change mitigation action entails more rapid transitions and higher up-front
    investments, but brings benefits from avoiding damages from climate change and
    reduced adaptation costs. The aggregate effects of climate change mitigation on
    global GDP  are small compared to global projected GDP growth. Projected estimates
    of global aggregate net economic damages and the costs of adaptation generally
    increase with global warming level.  Cost-benefit analysis remains limited in
    its ability to represent all damages from climate change, including non-monetary
    damages, or to capture the heterogeneous nature of damages and the risk of catastrophic
    damages. Even without accounting for these factors or for the co-benefits of mitigation,
    the global benefits of limiting warming to 2°C exceed the cost of mitigation .
    This finding is robust against a wide range of assumptions about social preferences
    on inequalities and discounting over time . Limiting global warming to 1.5°C instead
    of 2°C would increase the costs of mitigation, but also increase the benefits
    in terms of reduced impacts and related risks and reduced adaptation needs 140.  Considering
    other sustainable development dimensions, such as the potentially strong economic
    benefits on human health from air quality improvement, may enhance the estimated
    benefits of mitigation . The economic effects of strengthened mitigation action
    vary across regions and countries, depending notably on economic structure, regional
    emissions reductions, policy design and level of international cooperation. Ambitious
    mitigation pathways imply large and sometimes disruptive changes in economic structure,
    with implications for near-term actions, equity , sustainability, and finance
    .
  C.1.1:
  - Long-Term Interactions Between Adaptation, Mitigation and Sustainable Development  Mitigation
    and adaptation can lead to synergies and trade-offs with sustainable development.
    Accelerated and equitable mitigation and adaptation bring benefits from avoiding
    damages from climate change and are critical to achieving sustainable development.
    Climate resilient development 138 pathways are progressively constrained by every
    increment of further warming. There is a rapidly closing window of opportunity
    to secure a liveable and sustainable future for all.
  - 'Advancing Integrated Climate Action for Sustainable  Development An inclusive,
    equitable approach to integrating adaptation, mitigation and development can advance
    sustainable development in the long term. Integrated responses can harness synergies
    for sustainable development and reduce trade-offs. Shifting development pathways
    towards sustainability and advancing climate resilient development is enabled
    when governments, civil society and the private sector make development choices
    that prioritise risk reduction, equity and justice, and when decision-making processes,
    finance and actions are integrated across governance levels, sectors and timeframes.
    Inclusive processes involving local knowledge and Indigenous Knowledge increase
    these prospects. However, opportunities for action differ substantially among
    and within regions, driven by historical and ongoing patterns of development.
    Accelerated financial support for developing countries is critical to enhance
    mitigation and adaptation action.  Policies that shift development pathways towards
    sustainability can broaden the portfolio of available mitigation and adaptation
    responses. Combining mitigation with action to shift development pathways, such
    as broader sectoral policies, approaches that induce lifestyle or behaviour changes,
    financial regulation, or macroeconomic policies can overcome barriers and open
    up a broader range of mitigation options. Integrated, inclusive planning and investment
    in everyday decisionmaking about urban infrastructure can significantly increase
    the adaptive capacity of urban and rural settlements. Coastal cities and settlements
    play an important role in advancing climate resilient development due to the high
    number of people living in the Low Elevation Coastal Zone, the escalating and
    climate compounded risk that they face, and their vital role in national economies
    and beyond .  Observed adverse impacts and related losses and damages, projected
    risks, trends in vulnerability, and adaptation limits demonstrate that transformation
    for sustainability and climate resilient development action is more urgent than
    previously assessed. Climate resilient development integrates adaptation and GHG
    mitigation to advance sustainable development for all. Climate resilient development
    pathways have been constrained by past development, emissions and climate change
    and are progressively constrained by every increment of warming, in particular
    beyond 1.5°C. Climate resilient development will not be possible in some regions
    and sub-regions if global warming exceeds 2°C. Safeguarding biodiversity and ecosystems
    is fundamental to climate resilient development, but biodiversity and ecosystem
    services have limited capacity to adapt to increasing global warming levels, making
    climate resilient development progressively harder to achieve beyond 1.5°C warming.  The
    cumulative scientific evidence is unequivocal: climate change is a threat to human
    well-being and planetary health . Any further delay in concerted anticipatory
    global action on adaptation and mitigation will miss a brief and rapidly closing
    window of opportunity to secure a liveable and sustainable future for all. Opportunities
    for near-term action are assessed in the following section.'
  - 'The Timing and Urgency of Climate Action  The magnitude and rate of climate change
    and associated risks depend strongly on near-term mitigation and adaptation actions
    . Global warming is more likely than not to reach 1.5°C between 2021 and 2040
    even under the very low GHG emission scenarios, and likely or very likely to exceed
    1.5°C under higher emissions scenarios 141. Many adaptation options have medium
    or high feasibility up to 1.5°C , but hard limits to adaptation have already been
    reached in some ecosystems and the effectiveness of adaptation to reduce climate
    risk will decrease with increasing warming. Societal choices and actions implemented
    in this decade determine the extent to which medium- and long-term pathways will
    deliver higher or lower climate resilient development. Climate resilient development
    prospects are increasingly limited if current greenhouse gas emissions do not
    rapidly decline, especially if 1.5°C global warming is exceeded in the near term.
    Without urgent, effective and equitable adaptation and mitigation actions, climate
    change increasingly threatens the health and livelihoods of people around the
    globe, ecosystem health, and biodiversity, with severe adverse consequences for
    current and future generations. .  In modelled pathways that limit warming to
    1.5°C with no or limited overshoot and in those that limit warming to 2°C, assuming
    immediate actions, global GHG emissions are projected to peak in the early 2020s
    followed by rapid and deep GHG emissions reductions 142 . In pathways that limit
    warming to 1.5°C with no or limited overshoot, net global GHG emissions are projected
    to fall by 43 [34 to 60]%143 below 2019 levels by 2030, 60 [49 to 77]% by 2035,
    69 [58 to 90]% by 2040 and 84 [73 to 98]% by 2050 144. Global modelled pathways
    that limit warming to 2°C have reductions in GHG emissions below 2019 levels of
    21 [1 to 42]% by 2030, 35 [22 to 55] % by 2035, 46 [34 to 63] % by 2040 and 64
    [53 to 77]% by 2050145. Global GHG emissions associated with NDCs announced prior
    to COP26 would make it likely that warming would exceed 1.5°C and limiting warming
    to 2°C would then imply a rapid acceleration of emission reductions during 2030–2050,
    around 70% faster than in pathways where immediate action is taken to limit warming
    to 2°C Continued investments in unabated high-emitting infrastructure and limited
    development and deployment of low-emitting alternatives prior to 2030 would act
    as barriers to this acceleration and increase feasibility risks.  All global modelled
    pathways that limit warming to 2°C or lower by 2100 involve reductions in both
    net CO 2 emissions and non-CO 2 emissions. For example, in pathways that limit
    warming to 1.5°C with no or limited overshoot, global CH4 emissions are reduced
    by 34 [21 to 57]% below 2019 levels by 2030 and by 44 [31 to 63]% in 2040. Global
    CH 4 emissions are reduced by 24 [9 to 53]% below 2019 levels by 2030 and by 37
    [20 to 60]% in 2040 in modelled pathways that limit warming to 2°C with action
    starting in 2020.  All global modelled pathways that limit warming to 2°C or lower
    by 2100 involve GHG emission reductions in all sectors . The contributions of
    different sectors vary across modelled mitigation pathways. In most global modelled
    mitigation pathways, emissions from land-use, land-use change and forestry, via
    reforestation and reduced deforestation, and from the energy supply sector reach
    net zero CO2 emissions earlier than the buildings, industry and transport sectors.
    Strategies can rely on combinations of different options, but doing less in one
    sector needs to be compensated by further reductions in other sectors if warming
    is to be limited.  Without rapid, deep and sustained mitigation and accelerated
    adaptation actions, losses and damages will continue to increase, including projected
    adverse impacts in Africa, LDCs, SIDS, Central and South America , Asia and the
    Arctic, and will disproportionately affect the most vulnerable populations .  '
  C.1.2:
  - Long-Term Interactions Between Adaptation, Mitigation and Sustainable Development  Mitigation
    and adaptation can lead to synergies and trade-offs with sustainable development.
    Accelerated and equitable mitigation and adaptation bring benefits from avoiding
    damages from climate change and are critical to achieving sustainable development.
    Climate resilient development 138 pathways are progressively constrained by every
    increment of further warming. There is a rapidly closing window of opportunity
    to secure a liveable and sustainable future for all.
  - 'Benefits of Strengthening Near-Term Action  Accelerated implementation of adaptation
    will improve well-being by reducing losses and damages, especially for vulnerable
    populations. Deep, rapid, and sustained mitigation actions would reduce future
    adaptation costs and losses and damages, enhance sustainable development co-benefits,
    avoid locking-in emission sources, and reduce stranded assets and irreversible
    climate changes. These near-term actions involve higher up-front investments and
    disruptive changes, which can be moderated by a range of enabling conditions and
    removal or reduction of barriers to feasibility. Accelerated implementation of
    adaptation responses will bring benefits to human well-being. As adaptation options
    often have long implementation times, long-term planning and accelerated implementation,
    particularly in this decade, is important to close adaptation gaps, recognising
    that constraints remain for some regions. The benefits to vulnerable populations
    would be high .  Near-term actions that limit global warming to close to 1.5°C
    would substantially reduce projected losses and damages related to climate change
    in human systems and ecosystems, compared to higher warming levels, but cannot
    eliminate them all . The magnitude and rate of climate change and associated risks
    depend strongly on near-term mitigation and adaptation actions, and projected
    adverse impacts and related losses and damages escalate with every increment of
    global warming. Delayed mitigation action will further increase global warming
    which will decrease the effectiveness of many adaptation options, including Ecosystem-based
    Adaptation and many water-related options, as well as increasing mitigation feasibility
    risks, such as for options based on ecosystems. Comprehensive, effective, and
    innovative responses integrating adaptation and mitigation can harness synergies
    and reduce trade-offs between adaptation and mitigation, as well as in meeting
    requirements for financing .  Mitigation actions will have other sustainable development
    co-benefits. Mitigation will improve air quality and human health in the near
    term notably because many air pollutants are co-emitted by GHG emitting sectors
    and because methane emissions leads to surface ozone formation. The benefits from
    air quality improvement include prevention of air pollution-related premature
    deaths, chronic diseases and damages to ecosystems and crops. The economic benefits
    for human health from air quality improvement arising from mitigation action can
    be of the same order of magnitude as mitigation costs, and potentially even larger
    . As methane has a short lifetime but is a potent GHG, strong, rapid and sustained
    reductions in methane emissions can limit near-term warming and improve air quality
    by reducing global surface ozone.  Challenges from delayed adaptation and mitigation
    actions include the risk of cost escalation, lock-in of infrastructure, stranded
    assets, and reduced feasibility and effectiveness of adaptation and mitigation
    options. The continued installation of unabated fossil fuel infrastructure will
    ‘lock-in’ GHG emissions. Limiting global warming to 2°C or below will leave a
    substantial amount of fossil fuels unburned and could strand considerable fossil
    fuel infrastructure , with globally discounted value projected to be around USD
    1 to 4 trillion from 2015 to 2050. Early actions would limit the size of these
    stranded assets, whereas delayed actions with continued investments in unabated
    high-emitting infrastructure and limited development and deployment of low-emitting
    alternatives prior to 2030 would raise future stranded assets to the higher end
    of the range – thereby acting as barriers and increasing political economy feasibility
    risks that may jeopardise efforts to limit global warming. .  Scaling-up near-term
    climate actions will mobilise a mix of low-cost and high-cost options. High-cost
    options, as in energy and infrastructure, are needed to avoid future lock-ins,
    foster innovation and initiate transformational changes. Climate resilient development
    pathways in support of sustainable development for all are shaped by equity, and
    social and climate justice. Embedding effective and equitable adaptation and mitigation
    in development planning can reduce vulnerability, conserve and restore ecosystems,
    and enable climate resilient development. This is especially challenging in localities
    with persistent development gaps and limited resources.  Scaling-up climate action
    may generate disruptive changes in economic structure with distributional consequences
    and need to reconcile divergent interests, values and worldviews, within and between
    countries. Deeper fiscal, financial, institutional and regulatory reforms can
    offset such adverse effects and unlock mitigation potentials. Societal choices
    and actions implemented in this decade will determine the extent to which medium
    and long-term development pathways will deliver higher or lower climate resilient
    development outcomes.  Enabling conditions would need to be strengthened in the
    nearterm and barriers reduced or removed to realise opportunities for deep and
    rapid adaptation and mitigation actions and climate resilient development. These
    enabling conditions are differentiated by national, regional and local circumstances
    and geographies, according to capabilities, and include: equity and inclusion
    in climate action, rapid and far-reaching transitions in sectors and system ,
    measures to achieve synergies and reduce tradeoffs with sustainable development
    goals, governance and policy improvements, access to finance, improved international
    cooperation and technology improvements, and integration of near-term actions
    across sectors, systems and regions.  Barriers to feasibility would need to be
    reduced or removed to deploy mitigation and adaptation options at scale. Many
    limits to feasibility and effectiveness of responses can be overcome by addressing
    a range of barriers, including economic, technological, institutional, social,
    environmental and geophysical barriers. The feasibility and effectiveness of options
    increase with integrated, multi-sectoral solutions that differentiate responses
    based on climate risk, cut across systems and address social inequities. Strengthened
    near-term actions in modelled cost-effective pathways that limit global warming
    to 2°C or lower, reduce the overall risk to the feasibility of the system transitions,
    compared to modelled pathways with delayed or uncoordinated action.  Integrating
    ambitious climate actions with macroeconomic policies under global uncertainty
    would provide benefits . This encompasses three main directions: economy-wide
    mainstreaming packages supporting options to improved sustainable low-emission
    economic recovery, development and job creation programs  safety nets and social
    protection in the transition; and broadened access to finance, technology and
    capacity-building and coordinated support to low-emission infrastructure , especially
    in developing regions, and under debt stress .'
  - Equity and Inclusion in Climate Change Action  Actions that prioritise equity,
    climate justice, social justice and inclusion lead to more sustainable outcomes,
    co-benefits, reduce trade-offs, support transformative change and advance climate
    resilient development. Adaptation responses are immediately needed to reduce rising
    climate risks, especially for the most vulnerable. Equity, inclusion and just
    transitions are key to progress on adaptation and deeper societal ambitions for
    accelerated mitigation. Adaptation and mitigation actions, across scales, sectors
    and regions, that prioritise equity, climate justice, rights-based approaches,
    social justice and inclusivity, lead to more sustainable outcomes, reduce trade-offs,
    support transformative change and advance climate resilient development . Redistributive
    policies across sectors and regions that shield the poor and vulnerable, social
    safety nets, equity, inclusion and just transitions, at all scales can enable
    deeper societal ambitions and resolve trade-offs with sustainable development
    goals., particularly education, hunger, poverty, gender and energy access . Mitigation
    efforts embedded within the wider development context can increase the pace, depth
    and breadth of emission reductions . Equity, inclusion and just transitions at
    all scales enable deeper societal ambitions for accelerated mitigation, and climate
    action more broadly. The complexity in risk of rising food prices, reduced household
    incomes, and health and climate-related malnutrition  and mortality increases
    with little or low levels of adaptation.  Regions and people with considerable
    development constraints have high vulnerability to climatic hazards. Adaptation
    outcomes for the most vulnerable within and across countries and regions are enhanced
    through approaches focusing on equity, inclusivity, and rights-based approaches,
    including 3.3 to 3.6 billion people living in contexts that are highly vulnerable
    to climate change. Vulnerability is higher in locations with poverty, governance
    challenges and limited access to basic services and resources, violent conflict
    and high levels of climate-sensitive livelihoods  . Several risks can be moderated
    with adaptation. The largest adaptation gaps exist among lower income population
    groups and adaptation progress is unevenly distributed with observed adaptation
    gaps. Present development challenges causing high vulnerability are influenced
    by historical and ongoing patterns of inequity such as colonialism, especially
    for many Indigenous Peoples and local communities. Vulnerability is exacerbated
    by inequity and marginalisation linked to gender, ethnicity, low income or combinations
    thereof, especially for many Indigenous Peoples and local communities.  Meaningful
    participation and inclusive planning, informed by cultural values, Indigenous
    Knowledge, local knowledge, and scientific knowledge can help address adaptation
    gaps and avoid maladaptation. Such actions with flexible pathways may encourage
    low-regret and timely actions . Integrating climate adaptation into social protection
    programmes, including cash transfers and public works programmes, would increase
    resilience to climate change, especially when supported by basic services and
    infrastructure.  Equity, inclusion, just transitions, broad and meaningful participation
    of all relevant actors in decision making at all scales enable deeper societal
    ambitions for accelerated mitigation, and climate action more broadly, and build
    social trust, support transformative changes and an equitable sharing of benefits
    and burdens. Equity remains a central element in the UN climate regime, notwithstanding
    shifts in differentiation between states over time and challenges in assessing
    fair shares. Ambitious mitigation pathways imply large and sometimes disruptive
    changes in economic structure, with significant distributional consequences, within
    and between countries, including shifting of income and employment during the
    transition from high to low emissions activities. While some jobs may be lost,
    low-emissions development can also open up opportunities to enhance skills and
    create jobs. Broadening equitable access to finance, technologies and governance
    that facilitate mitigation, and consideration of climate justice can help equitable
    sharing of benefits and burdens, especially for vulnerable countries and communities.  Development
    priorities among countries also reflect different starting points and contexts,
    and enabling conditions for shifting development pathways towards increased sustainability
    will therefore differ, giving rise to different needs . Implementing just transition
    principles through collective and participatory decision-making processes is an
    effective way of integrating equity principles into policies at all scales depending
    on national circumstances, while in several countries just transition commissions,
    task forces and national policies have been established .  Many economic and regulatory
    instruments have been effective in reducing emissions and practical experience
    has informed instrument design to improve them while addressing distributional
    goals and social acceptance. The design of behavioural interventions, including
    the way that choices are presented to consumers work synergistically with price
    signals, making the combination more effective. Individuals with high socio-economic
    status contribute disproportionately to emissions, and have the highest potential
    for emissions reductions, e.g., as citizens, investors, consumers, role models,
    and professionals . There are options on design of instruments such as taxes,
    subsidies, prices, and consumption-based approaches, complemented by regulatory
    instruments to reduce high-emissions consumption while improving equity and societal
    well-being. Behaviour and lifestyle changes to help end-users adopt low-GHG-intensive
    options can be supported by policies, infrastructure and technology with multiple
    co-benefits for societal well-being. Broadening equitable access to domestic and
    international finance, technologies and capacity can also act as a catalyst for
    accelerating mitigation and shifting development pathways in low-income contexts
    . Eradicating extreme poverty, energy poverty, and providing decent living standards
    to all in these regions in the context of achieving sustainable development objectives,
    in the near term, can be achieved without significant global emissions growth.
    Technology development, transfer, capacity building and financing can support
    developing countries/ regions leapfrogging or transitioning to low-emissions transport
    systems thereby providing multiple co-benefits . Climate resilient development
    is advanced when actors work in equitable, just and enabling ways to reconcile
    divergent interests, values and worldviews, toward equitable and just outcomes
    .
  - Near-Term Mitigation and Adaptation Actions  Rapid and far-reaching transitions
    across all sectors and systems are necessary to achieve deep and sustained emissions
    reductions and secure a liveable and sustainable future for all. These system
    transitions involve a significant upscaling of a wide portfolio of mitigation
    and adaptation options. Feasible, effective and low-cost options for mitigation
    and adaptation are already available, with differences across systems and regions.  Rapid
    and far-reaching transitions across all sectors and systems are necessary to achieve
    deep emissions reductions and secure a liveable and sustainable future for all.
    System transitions consistent with pathways that limit warming to 1.5°C with no
    or limited overshoot are more rapid and pronounced in the near-term than in those
    that limit warming to 2°C . Such a systemic change is unprecedented in terms of
    scale, but not necessarily in terms of speed. The system transitions make possible
    the transformative adaptation required for high levels of human health and well-being,
    economic and social resilience, ecosystem health, and planetary health.  Feasible,
    effective and low-cost options for mitigation and adaptation are already available.
    Mitigation options costing USD 100 tCO 2-eq–1 or less could reduce global GHG
    emissions by at least half the 2019 level by 2030  . The availability, feasibility
    152 and potential of mitigation or effectiveness of adaptation options in the
    near term differ across systems and regions.  Demand-side measures and new ways
    of end-use service provision can reduce global GHG emissions in end-use sectors
    by 40 to 70% by 2050 compared to baseline scenarios, while some regions and socioeconomic
    groups require additional energy and resources. Demand-side mitigation encompasses
    changes in infrastructure use, end-use technology adoption, and socio-cultural
    and behavioural change. .
  - Governance and Policy for Near-Term Climate Change Action  Effective climate action
    requires political commitment, well-aligned multi-level governance and institutional
    frameworks, laws, policies and strategies. It needs clear goals, adequate finance
    and financing tools, coordination across multiple policy domains, and inclusive
    governance processes. Many mitigation and adaptation policy instruments have been
    deployed successfully, and could support deep emissions reductions and climate
    resilience if scaled up and applied widely, depending on national circumstances.
    Adaptation and mitigation action benefits from drawing on diverse knowledge. Effective
    climate governance enables mitigation and adaptation by providing overall direction
    based on national circumstances, setting targets and priorities, mainstreaming
    climate action across policy domains and levels, based on national circumstances
    and in the context of international cooperation. Effective governance enhances
    monitoring and evaluation and regulatory certainty, prioritising inclusive, transparent
    and equitable decision-making, and improves access to finance and technology.
    These functions can be promoted by climate-relevant laws and plans, which are
    growing in number across sectors and regions, advancing mitigation outcomes and
    adaptation benefits . Climate laws have been growing in number and have helped
    deliver mitigation and adaptation outcomes .  Effective municipal, national and
    sub-national climate institutions, such as expert and co-ordinating bodies, enable
    co-produced, multi-scale decision-processes, build consensus for action among
    diverse interests, and inform strategy settings . This requires adequate institutional
    capacity at all levels. Vulnerabilities and climate risks are often reduced through
    carefully designed and implemented laws, policies, participatory processes, and
    interventions that address context specific inequities such as based on gender,
    ethnicity, disability, age, location and income. Policy support is influenced
    by Indigenous Peoples, businesses, and actors in civil society, including, youth,
    labour, media, and local communities, and effectiveness is enhanced by partnerships
    between many different groups in society . Climate-related litigation is growing,
    with a large number of cases in some developed countries and with a much smaller
    number in some developing countries, and in some cases has influenced the outcome
    and ambition of climate governance.  Effective climate governance is enabled by
    inclusive decision processes, allocation of appropriate resources, and institutional
    review, monitoring and evaluation. Multi-level, hybrid and cross-sector governance
    facilitates appropriate consideration for co-benefits and trade-offs, particularly
    in land sectors where decision processes range from farm level to national scale.
    Consideration of climate justice can help to facilitate shifting development pathways
    towards sustainability.  Drawing on diverse knowledge and partnerships, including
    with women, youth, Indigenous Peoples, local communities, and ethnic minorities
    can facilitate climate resilient development and has allowed locally appropriate
    and socially acceptable solutions.  Many regulatory and economic instruments have
    already been deployed successfully. These instruments could support deep emissions
    reductions if scaled up and applied more widely. Practical experience has informed
    instrument design and helped to improve predictability, environmental effectiveness,
    economic efficiency, and equity.  Scaling up and enhancing the use of regulatory
    instruments, consistent with national circumstances, can improve mitigation outcomes
    in sectoral applications, and regulatory instruments that include flexibility
    mechanisms can reduce costs of cutting emissions.  Where implemented, carbon pricing
    instruments have incentivized low-cost emissions reduction measures, but have
    been less effective, on their own and at prevailing prices during the assessment
    period, to promote higher-cost measures necessary for further reductions. Revenue
    from carbon taxes or emissions trading can be used for equity and distributional
    goals, for example to support low-income households, among other approaches. There
    is no consistent evidence that current emission trading systems have led to significant
    emissions leakage.  Removing fossil fuel subsidies would reduce emissions, improve
    public revenue and macroeconomic performance, and yield other environmental and
    sustainable development benefits such as improved public revenue, macroeconomic
    and sustainability performance; subsidy removal can have adverse distributional
    impacts especially on the most economically vulnerable groups which, in some cases,
    can be mitigated by measures such as re-distributing revenue saved, and depend
    on national circumstances. Fossil fuel subsidy removal is projected by various
    studies to reduce global CO 2 emissions by 1–4%, and GHG emissions by up to 10%
    by 2030, varying across regions .  National policies to support technology development,
    and participation in international markets for emission reduction, can bring positive
    spillover effects for other countries , although reduced demand for fossil fuels
    as a result of climate policy could result in costs to exporting countries . Economy-wide
    packages can meet short-term economic goals while reducing emissions and shifting
    development pathways towards sustainability. Examples are public spending commitments;
    pricing reforms; and investment in education and training, R&D and infrastructure.
    Effective policy packages would be comprehensive in coverage, harnessed to a clear
    vision for change, balanced across objectives, aligned with specific technology
    and system needs, consistent in terms of design and tailored to national circumstances
    .
  - 'Strengthening the Response: Finance, International Cooperation and Technology  Finance,
    international cooperation and technology are critical enablers for accelerated
    climate action. If climate goals are to be achieved, both adaptation and mitigation
    financing would have to increase many-fold. There is sufficient global capital
    to close the global investment gaps but there are barriers to redirect capital
    to climate action. Barriers include institutional, regulatory and market access
    barriers, which can be reduced to address the needs and opportunities, economic
    vulnerability and indebtedness in many developing countries. Enhancing international
    cooperation is possible through multiple channels. Enhancing technology innovation
    systems is key to accelerate the widespread adoption of technologies and practices.'
  C.1.3:
  - 'The Likelihood and Risks of Abrupt and Irreversible  Change The likelihood of
    abrupt and irreversible changes and their impacts increase with higher global
    warming levels. As warming levels increase, so do the risks of species extinction
    or irreversible loss of biodiversity in ecosystems such as forests , coral reefs
    and in Arctic regions . Risks associated with large-scale singular events or tipping
    points, such as ice sheet instability or ecosystem loss from tropical forests,
    transition to high risk between 1.5°C to 2.5°C  and to very high risk between
    2.5°C to 4°C. The response of biogeochemical cycles to anthropogenic perturbations
    can be abrupt at regional scales and irreversible on decadal to century time scales.
    The probability of crossing uncertain regional thresholds increases with further
    warming.  Sea level rise is unavoidable for centuries to millennia due to continuing
    deep ocean warming and ice sheet melt, and sea levels will remain elevated for
    thousands of years . Global mean sea level rise will continue in the 21st century,
    with projected regional relative sea level rise within 20% of the global mean
    along two-thirds of the global coastline . The magnitude, the rate, the timing
    of threshold exceedances, and the long-term commitment of sea level rise depend
    on emissions, with higher emissions leading to greater and faster rates of sea
    level rise. Due to relative sea level rise, extreme sea level events that occurred
    once per century in the recent past are projected to occur at least annually at
    more than half of all tide gauge locations by 2100 and risks for coastal ecosystems,
    people and infrastructure will continue to increase beyond 2100. At sustained
    warming levels between 2°C and 3°C, the Greenland and West Antarctic ice sheets
    will be lost almost completely and irreversibly over multiple millennia. The probability
    and rate of ice mass loss increase with higher global surface temperatures. Over
    the next 2000 years, global mean sea level will rise by about 2 to 3 m if warming
    is limited to 1.5°C and 2 to 6 m if limited to 2°C . Projections of multi-millennial
    global mean sea level rise are consistent with reconstructed levels during past
    warm climate periods: global mean sea level was very likely 5 to 25 m higher than
    today roughly 3 million years ago, when global temperatures were 2.5°C to 4°C
    higher than 1850–1900. Further examples of unavoidable changes in the climate
    system due to multi-decadal or longer response timescales include continued glacier
    melt  and permafrost carbon loss.  The probability of low-likelihood outcomes
    associated with potentially very large impacts increases with higher global warming
    levels. Warming substantially above the assessed very likely range for a given
    scenario cannot be ruled out, and there is high confidence this would lead to
    regional changes greater than assessed in many aspects of the climate system.
    Low-likelihood, high-impact outcomes could occur at regional scales even for global
    warming within the very likely assessed range for a given GHG emissions scenario.
    Global mean sea level rise above the likely range – approaching 2 m by 2100 and
    in excess of 15 m by 2300 under a very high GHG emissions scenario  – cannot be
    ruled out due to deep uncertainty in ice-sheet processes 123 and would have severe
    impacts on populations in low elevation coastal zones. If global warming increases,
    some compound extreme events 124 will become more frequent, with higher likelihood
    of unprecedented intensities, durations or spatial extent. The Atlantic Meridional
    Overturning Circulation is very likely to weaken over the 21st century for all
    considered scenarios, however an abrupt collapse is not expected before 2100 .
    If such a low probability event were to occur, it would very likely cause abrupt
    shifts in regional weather patterns and water cycle, such as a southward shift
    in the tropical rain belt, and large impacts on ecosystems and human activities.
    A sequence of large explosive volcanic eruptions within decades, as have occurred
    in the past, is a low-likelihood high-impact event that would lead to substantial
    cooling globally and regional climate perturbations over several decades.'
  - 'Sectoral Contributions to Mitigation  All global modelled pathways that limit
    warming to 2°C or lower by 2100 involve rapid and deep and in most cases immediate
    GHG emissions reductions in all sectors. Reductions in GHG emissions in industry,
    transport, buildings, and urban areas can be achieved through a combination of
    energy efficiency and conservation and a transition to low-GHG technologies and
    energy carriers. Socio-cultural options and behavioural change can reduce global
    GHG emissions of end-use sectors, with most of the potential in developed countries,
    if combined with improved infrastructure design and access.  Global modelled mitigation
    pathways reaching net zero CO2 and GHG emissions include transitioning from fossil
    fuels without carbon capture and storage to very low- or zero-carbon energy sources,
    such as renewables or fossil fuels with CCS, demand-side measures and improving
    efficiency, reducing non-CO2 GHG emissions, and CDR 136. In global modelled pathways
    that limit warming to 2°C or below, almost all electricity is supplied from zero
    or low-carbon sources in 2050, such as renewables or fossil fuels with CO2 capture
    and storage, combined with increased electrification of energy demand. Such pathways
    meet energy service demand with relatively low energy use, through e.g., enhanced
    energy efficiency and behavioural changes and increased electrification of energy
    end use. Modelled global pathways limiting global warming to 1.5°C with no or
    limited overshoot generally implement such changes faster than pathways limiting
    global warming to 2°C.  AFOLU mitigation options, when sustainably implemented,
    can deliver large-scale GHG emission reductions and enhanced CO2 removal; however,
    barriers to implementation and trade-offs may result from the impacts of climate
    change, competing demands on land, conflicts with food security and livelihoods,
    the complexity of land ownership and management systems, and cultural aspects.
    All assessed modelled pathways that limit warming to 2°C or lower by 2100 include
    land-based mitigation and land-use change, with most including different combinations
    of reforestation, afforestation, reduced deforestation, and bioenergy. However,
    accumulated carbon in vegetation and soils is at risk from future loss triggered
    by climate change and disturbances such as flood, drought, fire, or pest outbreaks,
    or future poor management.  In addition to deep, rapid, and sustained emission
    reductions, CDR can fulfil three complementary roles: lowering net CO2 or net
    GHG emissions in the near term; counterbalancing ‘hard-to-abate’ residual emissions  to
    help reach net zero CO2 or GHG emissions, and achieving net negative CO 2 or GHG
    emissions if deployed at levels exceeding annual residual emissions. CDR methods
    vary in terms of their maturity, removal process, time scale of carbon storage,
    storage medium, mitigation potential, cost, co-benefits, impacts and risks, and
    governance requirements. Specifically, maturity ranges from lower maturity to
    higher maturity; removal and storage potential ranges from lower potential to
    higher potential; costs range from lower cost to higher cost  . Estimated storage
    timescales vary from decades to centuries for methods that store carbon in vegetation
    and through soil carbon management, to ten thousand years or more for methods
    that store carbon in geological formations . Afforestation, reforestation, improved
    forest management, agroforestry and soil carbon sequestration are currently the
    only widely practiced CDR methods. Methods and levels of CDR deployment in global
    modelled mitigation pathways vary depending on assumptions about costs, availability
    and constraints.'
  - Synergies and trade-offs, costs and benefits  Mitigation and adaptation options
    can lead to synergies and trade-offs with other aspects of sustainable development
    . Synergies and trade-offs depend on the pace and magnitude of changes and the
    development context including inequalities, with consideration of climate justice.
    The potential or effectiveness of some adaptation and mitigation options decreases
    as climate change intensifies .  In the energy sector, transitions to low-emission
    systems will have multiple co-benefits, including improvements in air quality
    and health. There are potential synergies between sustainable development and,
    for instance, energy efficiency and renewable energy.  For agriculture, land,
    and food systems, many land management options and demand-side response options  can
    contribute to eradicating poverty and eliminating hunger while promoting good
    health and well-being, clean water and sanitation, and life on land . In contrast,
    certain adaptation options that promote intensification of production, such as
    irrigation, may have negative effects on sustainability  .  Reforestation, improved
    forest management, soil carbon sequestration, peatland restoration and coastal
    blue carbon management are examples of CDR methods that can enhance biodiversity
    and ecosystem functions, employment and local livelihoods, depending on context
    . However, afforestation or production of biomass crops for bioenergy with carbon
    dioxide capture and storage or biochar can have adverse socio-economic and environmental
    impacts, including on biodiversity, food and water security, local livelihoods
    and the rights of Indigenous Peoples, especially if implemented at large scales
    and where land tenure is insecure.  Modelled pathways that assume using resources
    more efficiently or shift global development towards sustainability include fewer
    challenges, such as dependence on CDR and pressure on land and biodiversity, and
    have the most pronounced synergies with respect to sustainable development .  Strengthening
    climate change mitigation action entails more rapid transitions and higher up-front
    investments, but brings benefits from avoiding damages from climate change and
    reduced adaptation costs. The aggregate effects of climate change mitigation on
    global GDP  are small compared to global projected GDP growth. Projected estimates
    of global aggregate net economic damages and the costs of adaptation generally
    increase with global warming level.  Cost-benefit analysis remains limited in
    its ability to represent all damages from climate change, including non-monetary
    damages, or to capture the heterogeneous nature of damages and the risk of catastrophic
    damages. Even without accounting for these factors or for the co-benefits of mitigation,
    the global benefits of limiting warming to 2°C exceed the cost of mitigation .
    This finding is robust against a wide range of assumptions about social preferences
    on inequalities and discounting over time . Limiting global warming to 1.5°C instead
    of 2°C would increase the costs of mitigation, but also increase the benefits
    in terms of reduced impacts and related risks and reduced adaptation needs 140.  Considering
    other sustainable development dimensions, such as the potentially strong economic
    benefits on human health from air quality improvement, may enhance the estimated
    benefits of mitigation . The economic effects of strengthened mitigation action
    vary across regions and countries, depending notably on economic structure, regional
    emissions reductions, policy design and level of international cooperation. Ambitious
    mitigation pathways imply large and sometimes disruptive changes in economic structure,
    with implications for near-term actions, equity , sustainability, and finance
    .
  - 'The Timing and Urgency of Climate Action  The magnitude and rate of climate change
    and associated risks depend strongly on near-term mitigation and adaptation actions
    . Global warming is more likely than not to reach 1.5°C between 2021 and 2040
    even under the very low GHG emission scenarios, and likely or very likely to exceed
    1.5°C under higher emissions scenarios 141. Many adaptation options have medium
    or high feasibility up to 1.5°C , but hard limits to adaptation have already been
    reached in some ecosystems and the effectiveness of adaptation to reduce climate
    risk will decrease with increasing warming. Societal choices and actions implemented
    in this decade determine the extent to which medium- and long-term pathways will
    deliver higher or lower climate resilient development. Climate resilient development
    prospects are increasingly limited if current greenhouse gas emissions do not
    rapidly decline, especially if 1.5°C global warming is exceeded in the near term.
    Without urgent, effective and equitable adaptation and mitigation actions, climate
    change increasingly threatens the health and livelihoods of people around the
    globe, ecosystem health, and biodiversity, with severe adverse consequences for
    current and future generations. .  In modelled pathways that limit warming to
    1.5°C with no or limited overshoot and in those that limit warming to 2°C, assuming
    immediate actions, global GHG emissions are projected to peak in the early 2020s
    followed by rapid and deep GHG emissions reductions 142 . In pathways that limit
    warming to 1.5°C with no or limited overshoot, net global GHG emissions are projected
    to fall by 43 [34 to 60]%143 below 2019 levels by 2030, 60 [49 to 77]% by 2035,
    69 [58 to 90]% by 2040 and 84 [73 to 98]% by 2050 144. Global modelled pathways
    that limit warming to 2°C have reductions in GHG emissions below 2019 levels of
    21 [1 to 42]% by 2030, 35 [22 to 55] % by 2035, 46 [34 to 63] % by 2040 and 64
    [53 to 77]% by 2050145. Global GHG emissions associated with NDCs announced prior
    to COP26 would make it likely that warming would exceed 1.5°C and limiting warming
    to 2°C would then imply a rapid acceleration of emission reductions during 2030–2050,
    around 70% faster than in pathways where immediate action is taken to limit warming
    to 2°C Continued investments in unabated high-emitting infrastructure and limited
    development and deployment of low-emitting alternatives prior to 2030 would act
    as barriers to this acceleration and increase feasibility risks.  All global modelled
    pathways that limit warming to 2°C or lower by 2100 involve reductions in both
    net CO 2 emissions and non-CO 2 emissions. For example, in pathways that limit
    warming to 1.5°C with no or limited overshoot, global CH4 emissions are reduced
    by 34 [21 to 57]% below 2019 levels by 2030 and by 44 [31 to 63]% in 2040. Global
    CH 4 emissions are reduced by 24 [9 to 53]% below 2019 levels by 2030 and by 37
    [20 to 60]% in 2040 in modelled pathways that limit warming to 2°C with action
    starting in 2020.  All global modelled pathways that limit warming to 2°C or lower
    by 2100 involve GHG emission reductions in all sectors . The contributions of
    different sectors vary across modelled mitigation pathways. In most global modelled
    mitigation pathways, emissions from land-use, land-use change and forestry, via
    reforestation and reduced deforestation, and from the energy supply sector reach
    net zero CO2 emissions earlier than the buildings, industry and transport sectors.
    Strategies can rely on combinations of different options, but doing less in one
    sector needs to be compensated by further reductions in other sectors if warming
    is to be limited.  Without rapid, deep and sustained mitigation and accelerated
    adaptation actions, losses and damages will continue to increase, including projected
    adverse impacts in Africa, LDCs, SIDS, Central and South America , Asia and the
    Arctic, and will disproportionately affect the most vulnerable populations .  '
  - 'Benefits of Strengthening Near-Term Action  Accelerated implementation of adaptation
    will improve well-being by reducing losses and damages, especially for vulnerable
    populations. Deep, rapid, and sustained mitigation actions would reduce future
    adaptation costs and losses and damages, enhance sustainable development co-benefits,
    avoid locking-in emission sources, and reduce stranded assets and irreversible
    climate changes. These near-term actions involve higher up-front investments and
    disruptive changes, which can be moderated by a range of enabling conditions and
    removal or reduction of barriers to feasibility. Accelerated implementation of
    adaptation responses will bring benefits to human well-being. As adaptation options
    often have long implementation times, long-term planning and accelerated implementation,
    particularly in this decade, is important to close adaptation gaps, recognising
    that constraints remain for some regions. The benefits to vulnerable populations
    would be high .  Near-term actions that limit global warming to close to 1.5°C
    would substantially reduce projected losses and damages related to climate change
    in human systems and ecosystems, compared to higher warming levels, but cannot
    eliminate them all . The magnitude and rate of climate change and associated risks
    depend strongly on near-term mitigation and adaptation actions, and projected
    adverse impacts and related losses and damages escalate with every increment of
    global warming. Delayed mitigation action will further increase global warming
    which will decrease the effectiveness of many adaptation options, including Ecosystem-based
    Adaptation and many water-related options, as well as increasing mitigation feasibility
    risks, such as for options based on ecosystems. Comprehensive, effective, and
    innovative responses integrating adaptation and mitigation can harness synergies
    and reduce trade-offs between adaptation and mitigation, as well as in meeting
    requirements for financing .  Mitigation actions will have other sustainable development
    co-benefits. Mitigation will improve air quality and human health in the near
    term notably because many air pollutants are co-emitted by GHG emitting sectors
    and because methane emissions leads to surface ozone formation. The benefits from
    air quality improvement include prevention of air pollution-related premature
    deaths, chronic diseases and damages to ecosystems and crops. The economic benefits
    for human health from air quality improvement arising from mitigation action can
    be of the same order of magnitude as mitigation costs, and potentially even larger
    . As methane has a short lifetime but is a potent GHG, strong, rapid and sustained
    reductions in methane emissions can limit near-term warming and improve air quality
    by reducing global surface ozone.  Challenges from delayed adaptation and mitigation
    actions include the risk of cost escalation, lock-in of infrastructure, stranded
    assets, and reduced feasibility and effectiveness of adaptation and mitigation
    options. The continued installation of unabated fossil fuel infrastructure will
    ‘lock-in’ GHG emissions. Limiting global warming to 2°C or below will leave a
    substantial amount of fossil fuels unburned and could strand considerable fossil
    fuel infrastructure , with globally discounted value projected to be around USD
    1 to 4 trillion from 2015 to 2050. Early actions would limit the size of these
    stranded assets, whereas delayed actions with continued investments in unabated
    high-emitting infrastructure and limited development and deployment of low-emitting
    alternatives prior to 2030 would raise future stranded assets to the higher end
    of the range – thereby acting as barriers and increasing political economy feasibility
    risks that may jeopardise efforts to limit global warming. .  Scaling-up near-term
    climate actions will mobilise a mix of low-cost and high-cost options. High-cost
    options, as in energy and infrastructure, are needed to avoid future lock-ins,
    foster innovation and initiate transformational changes. Climate resilient development
    pathways in support of sustainable development for all are shaped by equity, and
    social and climate justice. Embedding effective and equitable adaptation and mitigation
    in development planning can reduce vulnerability, conserve and restore ecosystems,
    and enable climate resilient development. This is especially challenging in localities
    with persistent development gaps and limited resources.  Scaling-up climate action
    may generate disruptive changes in economic structure with distributional consequences
    and need to reconcile divergent interests, values and worldviews, within and between
    countries. Deeper fiscal, financial, institutional and regulatory reforms can
    offset such adverse effects and unlock mitigation potentials. Societal choices
    and actions implemented in this decade will determine the extent to which medium
    and long-term development pathways will deliver higher or lower climate resilient
    development outcomes.  Enabling conditions would need to be strengthened in the
    nearterm and barriers reduced or removed to realise opportunities for deep and
    rapid adaptation and mitigation actions and climate resilient development. These
    enabling conditions are differentiated by national, regional and local circumstances
    and geographies, according to capabilities, and include: equity and inclusion
    in climate action, rapid and far-reaching transitions in sectors and system ,
    measures to achieve synergies and reduce tradeoffs with sustainable development
    goals, governance and policy improvements, access to finance, improved international
    cooperation and technology improvements, and integration of near-term actions
    across sectors, systems and regions.  Barriers to feasibility would need to be
    reduced or removed to deploy mitigation and adaptation options at scale. Many
    limits to feasibility and effectiveness of responses can be overcome by addressing
    a range of barriers, including economic, technological, institutional, social,
    environmental and geophysical barriers. The feasibility and effectiveness of options
    increase with integrated, multi-sectoral solutions that differentiate responses
    based on climate risk, cut across systems and address social inequities. Strengthened
    near-term actions in modelled cost-effective pathways that limit global warming
    to 2°C or lower, reduce the overall risk to the feasibility of the system transitions,
    compared to modelled pathways with delayed or uncoordinated action.  Integrating
    ambitious climate actions with macroeconomic policies under global uncertainty
    would provide benefits . This encompasses three main directions: economy-wide
    mainstreaming packages supporting options to improved sustainable low-emission
    economic recovery, development and job creation programs  safety nets and social
    protection in the transition; and broadened access to finance, technology and
    capacity-building and coordinated support to low-emission infrastructure , especially
    in developing regions, and under debt stress .'
  - 'Near-Term Risks  Many changes in the climate system, including extreme events,
    will become larger in the near term with increasing global warming. Multiple climatic
    and non-climatic risks will interact, resulting in increased compounding and cascading
    impacts becoming more difficult to manage. Losses and damages will increase with
    increasing global warming, while strongly concentrated among the poorest vulnerable
    populations. Continuing with current unsustainable development patterns would
    increase exposure and vulnerability of ecosystems and people to climate hazards.
    Global warming will continue to increase in the near term mainly due to increased
    cumulative CO 2 emissions in nearly all considered scenarios and pathways. In
    the near term, every region in the world is projected to face further increases
    in climate hazards , increasing multiple risks to ecosystems and humans. In the
    near term, natural variability will modulate human-caused changes, either attenuating
    or amplifying projected changes, especially at regional scales, with little effect
    on centennial global warming. Those modulations are important to consider in adaptation
    planning. Global surface temperature in any single year can vary above or below
    the long-term human-induced trend, due to natural variability. By 2030, global
    surface temperature in any individual year could exceed 1.5°C relative to 1850–1900
    with a probability between 40% and 60%, across the five scenarios assessed in
    WGI. The occurrence of individual years with global surface temperature change
    above a certain level does not imply that this global warming level has been reached.
    If a large explosive volcanic eruption were to occur in the near term 150, it
    would temporarily and partially mask human-caused climate change by reducing global
    surface temperature and precipitation, especially over land, for one to three
    years.  The level of risk for humans and ecosystems will depend on near-term trends
    in vulnerability, exposure, level of socio-economic development and adaptation.
    In the near term, many climate-associated risks to natural and human systems depend
    more strongly on changes in these systems’ vulnerability and exposure than on
    differences in climate hazards between emissions scenarios . Future exposure to
    climatic hazards is increasing globally due to socio-economic development trends
    including growing inequality, and when urbanisation or migration increase exposure
    . Urbanisation increases hot extremes  and precipitation runoff intensity. Increasing
    urbanisation in low-lying and coastal zones will be a major driver of increasing
    exposure to extreme riverflow events and sea level rise hazards, increasing risks.
    Vulnerability will also rise rapidly in low-lying Small Island Developing States
    and atolls in the context of sea level rise . Human vulnerability will concentrate
    in informal settlements and rapidly growing smaller settlements; and vulnerability
    in rural areas will be heightened by reduced habitability and high reliance on
    climate-sensitive livelihoods. Human and ecosystem vulnerability are interdependent.
    Vulnerability to climate change for ecosystems will be strongly influenced by
    past, present, and future patterns of human development, including from unsustainable
    consumption and production, increasing demographic pressures, and persistent unsustainable
    use and management of land, ocean, and water. Several near-term risks can be moderated
    with adaptation.  Principal hazards and associated risks expected in the near
    term are: • Increased intensity and frequency of hot extremes and dangerous heat-humidity
    conditions, with increased human mortality, morbidity, and labour productivity
    loss.  • Increasing frequency of marine heatwaves will increase risks of biodiversity
    loss in the oceans, including from mass mortality events.  • Near-term risks for
    biodiversity loss are moderate to high in forest ecosystems and kelp and seagrass
    ecosystems and are high to very high in Arctic sea-ice and terrestrial ecosystems
    and warm-water coral reefs.  • More intense and frequent extreme rainfall and
    associated flooding in many regions including coastal and other low-lying cities
    , and increased proportion of and peak wind speeds of intense tropical cyclones.  •
    High risks from dryland water scarcity, wildfire damage, and permafrost degradation.  •
    Continued sea level rise and increased frequency and magnitude of extreme sea
    level events encroaching on coastal human settlements and damaging coastal infrastructure
    , committing low-lying coastal ecosystems to submergence and loss, expanding land
    salinization, with cascading to risks to livelihoods, health, well-being, cultural
    values, food and water security.  • Climate change will significantly increase
    ill health and premature deaths from the near to long term. Further warming will
    increase climate-sensitive food-borne, water-borne, and vector-borne disease risks,
    and mental health challenges including anxiety and stress.  Cryosphere-related
    changes in floods, landslides, and water availability have the potential to lead
    to severe consequences for people, infrastructure and the economy in most mountain
    regions .  • The projected increase in frequency and intensity of heavy precipitation
    will increase rain-generated local flooding.  Multiple climate change risks will
    increasingly compound and cascade in the near term. Many regions are projected
    to experience an increase in the probability of compound events with higher global
    warming including concurrent heatwaves and drought. Risks to health and food production
    will be made more severe from the interaction of sudden food production losses
    from heat and drought, exacerbated by heatinduced labour productivity losses.
    These interacting impacts will increase food prices, reduce household incomes,
    and lead to health risks of malnutrition and climate-related mortality with no
    or low levels of adaptation, especially in tropical regions . Concurrent and cascading
    risks from climate change to food systems, human settlements, infrastructure and
    health will make these risks more severe and more difficult to manage, including
    when interacting with non-climatic risk drivers such as competition for land between
    urban expansion and food production, and pandemics . Loss of ecosystems and their
    services has cascading and long-term impacts on people globally, especially for
    Indigenous Peoples and local communities who are directly dependent on ecosystems,
    to meet basic needs. Increasing transboundary risks are projected across the food,
    energy and water sectors as impacts from weather and climate extremes propagate
    through supply-chains, markets, and natural resource flows and may interact with
    impacts from other crises such as pandemics. Risks also arise from some responses
    intended to reduce the risks of climate change, including risks from maladaptation
    and adverse side effects of some emissions reduction and carbon dioxide removal
    measures, such as afforestation of naturally unforested land or poorly implemented
    bioenergy compounding climate-related risks to biodiversity, food and water security,
    and livelihoods.  With every increment of global warming losses and damages will
    increase, become increasingly difficult to avoid and be strongly concentrated
    among the poorest vulnerable populations. Adaptation does not prevent all losses
    and damages, even with effective adaptation and before reaching soft and hard
    limits. Losses and damages will be unequally distributed across systems, regions
    and sectors and are not comprehensively addressed by current financial, governance
    and institutional arrangements, particularly in vulnerable developing countries.
    .'
  - Equity and Inclusion in Climate Change Action  Actions that prioritise equity,
    climate justice, social justice and inclusion lead to more sustainable outcomes,
    co-benefits, reduce trade-offs, support transformative change and advance climate
    resilient development. Adaptation responses are immediately needed to reduce rising
    climate risks, especially for the most vulnerable. Equity, inclusion and just
    transitions are key to progress on adaptation and deeper societal ambitions for
    accelerated mitigation. Adaptation and mitigation actions, across scales, sectors
    and regions, that prioritise equity, climate justice, rights-based approaches,
    social justice and inclusivity, lead to more sustainable outcomes, reduce trade-offs,
    support transformative change and advance climate resilient development . Redistributive
    policies across sectors and regions that shield the poor and vulnerable, social
    safety nets, equity, inclusion and just transitions, at all scales can enable
    deeper societal ambitions and resolve trade-offs with sustainable development
    goals., particularly education, hunger, poverty, gender and energy access . Mitigation
    efforts embedded within the wider development context can increase the pace, depth
    and breadth of emission reductions . Equity, inclusion and just transitions at
    all scales enable deeper societal ambitions for accelerated mitigation, and climate
    action more broadly. The complexity in risk of rising food prices, reduced household
    incomes, and health and climate-related malnutrition  and mortality increases
    with little or low levels of adaptation.  Regions and people with considerable
    development constraints have high vulnerability to climatic hazards. Adaptation
    outcomes for the most vulnerable within and across countries and regions are enhanced
    through approaches focusing on equity, inclusivity, and rights-based approaches,
    including 3.3 to 3.6 billion people living in contexts that are highly vulnerable
    to climate change. Vulnerability is higher in locations with poverty, governance
    challenges and limited access to basic services and resources, violent conflict
    and high levels of climate-sensitive livelihoods  . Several risks can be moderated
    with adaptation. The largest adaptation gaps exist among lower income population
    groups and adaptation progress is unevenly distributed with observed adaptation
    gaps. Present development challenges causing high vulnerability are influenced
    by historical and ongoing patterns of inequity such as colonialism, especially
    for many Indigenous Peoples and local communities. Vulnerability is exacerbated
    by inequity and marginalisation linked to gender, ethnicity, low income or combinations
    thereof, especially for many Indigenous Peoples and local communities.  Meaningful
    participation and inclusive planning, informed by cultural values, Indigenous
    Knowledge, local knowledge, and scientific knowledge can help address adaptation
    gaps and avoid maladaptation. Such actions with flexible pathways may encourage
    low-regret and timely actions . Integrating climate adaptation into social protection
    programmes, including cash transfers and public works programmes, would increase
    resilience to climate change, especially when supported by basic services and
    infrastructure.  Equity, inclusion, just transitions, broad and meaningful participation
    of all relevant actors in decision making at all scales enable deeper societal
    ambitions for accelerated mitigation, and climate action more broadly, and build
    social trust, support transformative changes and an equitable sharing of benefits
    and burdens. Equity remains a central element in the UN climate regime, notwithstanding
    shifts in differentiation between states over time and challenges in assessing
    fair shares. Ambitious mitigation pathways imply large and sometimes disruptive
    changes in economic structure, with significant distributional consequences, within
    and between countries, including shifting of income and employment during the
    transition from high to low emissions activities. While some jobs may be lost,
    low-emissions development can also open up opportunities to enhance skills and
    create jobs. Broadening equitable access to finance, technologies and governance
    that facilitate mitigation, and consideration of climate justice can help equitable
    sharing of benefits and burdens, especially for vulnerable countries and communities.  Development
    priorities among countries also reflect different starting points and contexts,
    and enabling conditions for shifting development pathways towards increased sustainability
    will therefore differ, giving rise to different needs . Implementing just transition
    principles through collective and participatory decision-making processes is an
    effective way of integrating equity principles into policies at all scales depending
    on national circumstances, while in several countries just transition commissions,
    task forces and national policies have been established .  Many economic and regulatory
    instruments have been effective in reducing emissions and practical experience
    has informed instrument design to improve them while addressing distributional
    goals and social acceptance. The design of behavioural interventions, including
    the way that choices are presented to consumers work synergistically with price
    signals, making the combination more effective. Individuals with high socio-economic
    status contribute disproportionately to emissions, and have the highest potential
    for emissions reductions, e.g., as citizens, investors, consumers, role models,
    and professionals . There are options on design of instruments such as taxes,
    subsidies, prices, and consumption-based approaches, complemented by regulatory
    instruments to reduce high-emissions consumption while improving equity and societal
    well-being. Behaviour and lifestyle changes to help end-users adopt low-GHG-intensive
    options can be supported by policies, infrastructure and technology with multiple
    co-benefits for societal well-being. Broadening equitable access to domestic and
    international finance, technologies and capacity can also act as a catalyst for
    accelerating mitigation and shifting development pathways in low-income contexts
    . Eradicating extreme poverty, energy poverty, and providing decent living standards
    to all in these regions in the context of achieving sustainable development objectives,
    in the near term, can be achieved without significant global emissions growth.
    Technology development, transfer, capacity building and financing can support
    developing countries/ regions leapfrogging or transitioning to low-emissions transport
    systems thereby providing multiple co-benefits . Climate resilient development
    is advanced when actors work in equitable, just and enabling ways to reconcile
    divergent interests, values and worldviews, toward equitable and just outcomes
    .
  C.2.1:
  - 'The Timing and Urgency of Climate Action  The magnitude and rate of climate change
    and associated risks depend strongly on near-term mitigation and adaptation actions
    . Global warming is more likely than not to reach 1.5°C between 2021 and 2040
    even under the very low GHG emission scenarios, and likely or very likely to exceed
    1.5°C under higher emissions scenarios 141. Many adaptation options have medium
    or high feasibility up to 1.5°C , but hard limits to adaptation have already been
    reached in some ecosystems and the effectiveness of adaptation to reduce climate
    risk will decrease with increasing warming. Societal choices and actions implemented
    in this decade determine the extent to which medium- and long-term pathways will
    deliver higher or lower climate resilient development. Climate resilient development
    prospects are increasingly limited if current greenhouse gas emissions do not
    rapidly decline, especially if 1.5°C global warming is exceeded in the near term.
    Without urgent, effective and equitable adaptation and mitigation actions, climate
    change increasingly threatens the health and livelihoods of people around the
    globe, ecosystem health, and biodiversity, with severe adverse consequences for
    current and future generations. .  In modelled pathways that limit warming to
    1.5°C with no or limited overshoot and in those that limit warming to 2°C, assuming
    immediate actions, global GHG emissions are projected to peak in the early 2020s
    followed by rapid and deep GHG emissions reductions 142 . In pathways that limit
    warming to 1.5°C with no or limited overshoot, net global GHG emissions are projected
    to fall by 43 [34 to 60]%143 below 2019 levels by 2030, 60 [49 to 77]% by 2035,
    69 [58 to 90]% by 2040 and 84 [73 to 98]% by 2050 144. Global modelled pathways
    that limit warming to 2°C have reductions in GHG emissions below 2019 levels of
    21 [1 to 42]% by 2030, 35 [22 to 55] % by 2035, 46 [34 to 63] % by 2040 and 64
    [53 to 77]% by 2050145. Global GHG emissions associated with NDCs announced prior
    to COP26 would make it likely that warming would exceed 1.5°C and limiting warming
    to 2°C would then imply a rapid acceleration of emission reductions during 2030–2050,
    around 70% faster than in pathways where immediate action is taken to limit warming
    to 2°C Continued investments in unabated high-emitting infrastructure and limited
    development and deployment of low-emitting alternatives prior to 2030 would act
    as barriers to this acceleration and increase feasibility risks.  All global modelled
    pathways that limit warming to 2°C or lower by 2100 involve reductions in both
    net CO 2 emissions and non-CO 2 emissions. For example, in pathways that limit
    warming to 1.5°C with no or limited overshoot, global CH4 emissions are reduced
    by 34 [21 to 57]% below 2019 levels by 2030 and by 44 [31 to 63]% in 2040. Global
    CH 4 emissions are reduced by 24 [9 to 53]% below 2019 levels by 2030 and by 37
    [20 to 60]% in 2040 in modelled pathways that limit warming to 2°C with action
    starting in 2020.  All global modelled pathways that limit warming to 2°C or lower
    by 2100 involve GHG emission reductions in all sectors . The contributions of
    different sectors vary across modelled mitigation pathways. In most global modelled
    mitigation pathways, emissions from land-use, land-use change and forestry, via
    reforestation and reduced deforestation, and from the energy supply sector reach
    net zero CO2 emissions earlier than the buildings, industry and transport sectors.
    Strategies can rely on combinations of different options, but doing less in one
    sector needs to be compensated by further reductions in other sectors if warming
    is to be limited.  Without rapid, deep and sustained mitigation and accelerated
    adaptation actions, losses and damages will continue to increase, including projected
    adverse impacts in Africa, LDCs, SIDS, Central and South America , Asia and the
    Arctic, and will disproportionately affect the most vulnerable populations .  '
  - 'Benefits of Strengthening Near-Term Action  Accelerated implementation of adaptation
    will improve well-being by reducing losses and damages, especially for vulnerable
    populations. Deep, rapid, and sustained mitigation actions would reduce future
    adaptation costs and losses and damages, enhance sustainable development co-benefits,
    avoid locking-in emission sources, and reduce stranded assets and irreversible
    climate changes. These near-term actions involve higher up-front investments and
    disruptive changes, which can be moderated by a range of enabling conditions and
    removal or reduction of barriers to feasibility. Accelerated implementation of
    adaptation responses will bring benefits to human well-being. As adaptation options
    often have long implementation times, long-term planning and accelerated implementation,
    particularly in this decade, is important to close adaptation gaps, recognising
    that constraints remain for some regions. The benefits to vulnerable populations
    would be high .  Near-term actions that limit global warming to close to 1.5°C
    would substantially reduce projected losses and damages related to climate change
    in human systems and ecosystems, compared to higher warming levels, but cannot
    eliminate them all . The magnitude and rate of climate change and associated risks
    depend strongly on near-term mitigation and adaptation actions, and projected
    adverse impacts and related losses and damages escalate with every increment of
    global warming. Delayed mitigation action will further increase global warming
    which will decrease the effectiveness of many adaptation options, including Ecosystem-based
    Adaptation and many water-related options, as well as increasing mitigation feasibility
    risks, such as for options based on ecosystems. Comprehensive, effective, and
    innovative responses integrating adaptation and mitigation can harness synergies
    and reduce trade-offs between adaptation and mitigation, as well as in meeting
    requirements for financing .  Mitigation actions will have other sustainable development
    co-benefits. Mitigation will improve air quality and human health in the near
    term notably because many air pollutants are co-emitted by GHG emitting sectors
    and because methane emissions leads to surface ozone formation. The benefits from
    air quality improvement include prevention of air pollution-related premature
    deaths, chronic diseases and damages to ecosystems and crops. The economic benefits
    for human health from air quality improvement arising from mitigation action can
    be of the same order of magnitude as mitigation costs, and potentially even larger
    . As methane has a short lifetime but is a potent GHG, strong, rapid and sustained
    reductions in methane emissions can limit near-term warming and improve air quality
    by reducing global surface ozone.  Challenges from delayed adaptation and mitigation
    actions include the risk of cost escalation, lock-in of infrastructure, stranded
    assets, and reduced feasibility and effectiveness of adaptation and mitigation
    options. The continued installation of unabated fossil fuel infrastructure will
    ‘lock-in’ GHG emissions. Limiting global warming to 2°C or below will leave a
    substantial amount of fossil fuels unburned and could strand considerable fossil
    fuel infrastructure , with globally discounted value projected to be around USD
    1 to 4 trillion from 2015 to 2050. Early actions would limit the size of these
    stranded assets, whereas delayed actions with continued investments in unabated
    high-emitting infrastructure and limited development and deployment of low-emitting
    alternatives prior to 2030 would raise future stranded assets to the higher end
    of the range – thereby acting as barriers and increasing political economy feasibility
    risks that may jeopardise efforts to limit global warming. .  Scaling-up near-term
    climate actions will mobilise a mix of low-cost and high-cost options. High-cost
    options, as in energy and infrastructure, are needed to avoid future lock-ins,
    foster innovation and initiate transformational changes. Climate resilient development
    pathways in support of sustainable development for all are shaped by equity, and
    social and climate justice. Embedding effective and equitable adaptation and mitigation
    in development planning can reduce vulnerability, conserve and restore ecosystems,
    and enable climate resilient development. This is especially challenging in localities
    with persistent development gaps and limited resources.  Scaling-up climate action
    may generate disruptive changes in economic structure with distributional consequences
    and need to reconcile divergent interests, values and worldviews, within and between
    countries. Deeper fiscal, financial, institutional and regulatory reforms can
    offset such adverse effects and unlock mitigation potentials. Societal choices
    and actions implemented in this decade will determine the extent to which medium
    and long-term development pathways will deliver higher or lower climate resilient
    development outcomes.  Enabling conditions would need to be strengthened in the
    nearterm and barriers reduced or removed to realise opportunities for deep and
    rapid adaptation and mitigation actions and climate resilient development. These
    enabling conditions are differentiated by national, regional and local circumstances
    and geographies, according to capabilities, and include: equity and inclusion
    in climate action, rapid and far-reaching transitions in sectors and system ,
    measures to achieve synergies and reduce tradeoffs with sustainable development
    goals, governance and policy improvements, access to finance, improved international
    cooperation and technology improvements, and integration of near-term actions
    across sectors, systems and regions.  Barriers to feasibility would need to be
    reduced or removed to deploy mitigation and adaptation options at scale. Many
    limits to feasibility and effectiveness of responses can be overcome by addressing
    a range of barriers, including economic, technological, institutional, social,
    environmental and geophysical barriers. The feasibility and effectiveness of options
    increase with integrated, multi-sectoral solutions that differentiate responses
    based on climate risk, cut across systems and address social inequities. Strengthened
    near-term actions in modelled cost-effective pathways that limit global warming
    to 2°C or lower, reduce the overall risk to the feasibility of the system transitions,
    compared to modelled pathways with delayed or uncoordinated action.  Integrating
    ambitious climate actions with macroeconomic policies under global uncertainty
    would provide benefits . This encompasses three main directions: economy-wide
    mainstreaming packages supporting options to improved sustainable low-emission
    economic recovery, development and job creation programs  safety nets and social
    protection in the transition; and broadened access to finance, technology and
    capacity-building and coordinated support to low-emission infrastructure , especially
    in developing regions, and under debt stress .'
  - 'Near-Term Risks  Many changes in the climate system, including extreme events,
    will become larger in the near term with increasing global warming. Multiple climatic
    and non-climatic risks will interact, resulting in increased compounding and cascading
    impacts becoming more difficult to manage. Losses and damages will increase with
    increasing global warming, while strongly concentrated among the poorest vulnerable
    populations. Continuing with current unsustainable development patterns would
    increase exposure and vulnerability of ecosystems and people to climate hazards.
    Global warming will continue to increase in the near term mainly due to increased
    cumulative CO 2 emissions in nearly all considered scenarios and pathways. In
    the near term, every region in the world is projected to face further increases
    in climate hazards , increasing multiple risks to ecosystems and humans. In the
    near term, natural variability will modulate human-caused changes, either attenuating
    or amplifying projected changes, especially at regional scales, with little effect
    on centennial global warming. Those modulations are important to consider in adaptation
    planning. Global surface temperature in any single year can vary above or below
    the long-term human-induced trend, due to natural variability. By 2030, global
    surface temperature in any individual year could exceed 1.5°C relative to 1850–1900
    with a probability between 40% and 60%, across the five scenarios assessed in
    WGI. The occurrence of individual years with global surface temperature change
    above a certain level does not imply that this global warming level has been reached.
    If a large explosive volcanic eruption were to occur in the near term 150, it
    would temporarily and partially mask human-caused climate change by reducing global
    surface temperature and precipitation, especially over land, for one to three
    years.  The level of risk for humans and ecosystems will depend on near-term trends
    in vulnerability, exposure, level of socio-economic development and adaptation.
    In the near term, many climate-associated risks to natural and human systems depend
    more strongly on changes in these systems’ vulnerability and exposure than on
    differences in climate hazards between emissions scenarios . Future exposure to
    climatic hazards is increasing globally due to socio-economic development trends
    including growing inequality, and when urbanisation or migration increase exposure
    . Urbanisation increases hot extremes  and precipitation runoff intensity. Increasing
    urbanisation in low-lying and coastal zones will be a major driver of increasing
    exposure to extreme riverflow events and sea level rise hazards, increasing risks.
    Vulnerability will also rise rapidly in low-lying Small Island Developing States
    and atolls in the context of sea level rise . Human vulnerability will concentrate
    in informal settlements and rapidly growing smaller settlements; and vulnerability
    in rural areas will be heightened by reduced habitability and high reliance on
    climate-sensitive livelihoods. Human and ecosystem vulnerability are interdependent.
    Vulnerability to climate change for ecosystems will be strongly influenced by
    past, present, and future patterns of human development, including from unsustainable
    consumption and production, increasing demographic pressures, and persistent unsustainable
    use and management of land, ocean, and water. Several near-term risks can be moderated
    with adaptation.  Principal hazards and associated risks expected in the near
    term are: • Increased intensity and frequency of hot extremes and dangerous heat-humidity
    conditions, with increased human mortality, morbidity, and labour productivity
    loss.  • Increasing frequency of marine heatwaves will increase risks of biodiversity
    loss in the oceans, including from mass mortality events.  • Near-term risks for
    biodiversity loss are moderate to high in forest ecosystems and kelp and seagrass
    ecosystems and are high to very high in Arctic sea-ice and terrestrial ecosystems
    and warm-water coral reefs.  • More intense and frequent extreme rainfall and
    associated flooding in many regions including coastal and other low-lying cities
    , and increased proportion of and peak wind speeds of intense tropical cyclones.  •
    High risks from dryland water scarcity, wildfire damage, and permafrost degradation.  •
    Continued sea level rise and increased frequency and magnitude of extreme sea
    level events encroaching on coastal human settlements and damaging coastal infrastructure
    , committing low-lying coastal ecosystems to submergence and loss, expanding land
    salinization, with cascading to risks to livelihoods, health, well-being, cultural
    values, food and water security.  • Climate change will significantly increase
    ill health and premature deaths from the near to long term. Further warming will
    increase climate-sensitive food-borne, water-borne, and vector-borne disease risks,
    and mental health challenges including anxiety and stress.  Cryosphere-related
    changes in floods, landslides, and water availability have the potential to lead
    to severe consequences for people, infrastructure and the economy in most mountain
    regions .  • The projected increase in frequency and intensity of heavy precipitation
    will increase rain-generated local flooding.  Multiple climate change risks will
    increasingly compound and cascade in the near term. Many regions are projected
    to experience an increase in the probability of compound events with higher global
    warming including concurrent heatwaves and drought. Risks to health and food production
    will be made more severe from the interaction of sudden food production losses
    from heat and drought, exacerbated by heatinduced labour productivity losses.
    These interacting impacts will increase food prices, reduce household incomes,
    and lead to health risks of malnutrition and climate-related mortality with no
    or low levels of adaptation, especially in tropical regions . Concurrent and cascading
    risks from climate change to food systems, human settlements, infrastructure and
    health will make these risks more severe and more difficult to manage, including
    when interacting with non-climatic risk drivers such as competition for land between
    urban expansion and food production, and pandemics . Loss of ecosystems and their
    services has cascading and long-term impacts on people globally, especially for
    Indigenous Peoples and local communities who are directly dependent on ecosystems,
    to meet basic needs. Increasing transboundary risks are projected across the food,
    energy and water sectors as impacts from weather and climate extremes propagate
    through supply-chains, markets, and natural resource flows and may interact with
    impacts from other crises such as pandemics. Risks also arise from some responses
    intended to reduce the risks of climate change, including risks from maladaptation
    and adverse side effects of some emissions reduction and carbon dioxide removal
    measures, such as afforestation of naturally unforested land or poorly implemented
    bioenergy compounding climate-related risks to biodiversity, food and water security,
    and livelihoods.  With every increment of global warming losses and damages will
    increase, become increasingly difficult to avoid and be strongly concentrated
    among the poorest vulnerable populations. Adaptation does not prevent all losses
    and damages, even with effective adaptation and before reaching soft and hard
    limits. Losses and damages will be unequally distributed across systems, regions
    and sectors and are not comprehensively addressed by current financial, governance
    and institutional arrangements, particularly in vulnerable developing countries.
    .'
  C.2.2:
  - Observed Climate System Changes and Impacts to  Date It is unequivocal that human
    influence has warmed the atmosphere, ocean and land. Widespread and rapid changes
    in the atmosphere, ocean, cryosphere and biosphere have occurred . The scale of
    recent changes across the climate system as a whole and the present state of many
    aspects of the climate system are unprecedented over many centuries to many thousands
    of years. It is very likely that GHG emissions were the main driver of tropospheric
    warming and extremely likely that human-caused stratospheric ozone depletion was
    the main driver of stratospheric cooling between 1979 and the mid-1990s. It is
    virtually certain that the global upper ocean has warmed since the 1970s and extremely
    likely that human influence is the main driver. Ocean warming accounted for 91%
    of the heating in the climate system, with land warming, ice loss and atmospheric
    warming accounting for about 5%, 3% and 1%, respectively. Global mean sea level
    increased by 0.20 [0.15 to 0.25] m between 1901 and 2018. The average rate of
    sea level rise was 1.3 [0.6 to 2.1]mm yr-1 between 1901 and 1971, increasing to
    1.9 [0.8 to 2.9] mm yr-1 between 1971 and 2006, and further increasing to 3.7
    [3.2 to –4.2] mm yr -1 between 2006 and 2018. Human influence was very likely
    the main driver of these increases since at least 1971. Human influence is very
    likely the main driver of the global retreat of glaciers since the 1990s and the
    decrease in Arctic sea ice area between 1979–1988 and 2010–2019. Human influence
    has also very likely contributed to decreased Northern Hemisphere spring snow
    cover and surface melting of the Greenland ice sheet. It is virtually certain
    that human-caused CO2 emissions are the main driver of current global acidification
    of the surface open ocean.  Human-caused climate change is already affecting many
    weather and climate extremes in every region across the globe. Evidence of observed
    changes in extremes such as heatwaves, heavy precipitation, droughts, and tropical
    cyclones, and, in particular, their attribution to human influence, has strengthened
    since AR5. It is virtually certain that hot extremes have become more frequent
    and more intense across most land regions since the 1950s, while cold extremes
    have become less frequent and less severe, with high confidence that human-caused
    climate change is the main driver of these changes. Marine heatwaves have approximately
    doubled in frequency since the 1980s, and human influence has very likely contributed
    to most of them since at least 2006. The frequency and intensity of heavy precipitation
    events have increased since the 1950s over most land areas for which observational
    data are sufficient for trend analysis, and human-caused climate change is likely
    the main driver. Human-caused climate change has contributed to increases in agricultural
    and ecological droughts in some regions due to increased land evapotranspiration
    . It is likely that the global proportion of major tropical cyclone occurrence
    has increased over the last four decades.  Climate change has caused substantial
    damages, and increasingly irreversible losses, in terrestrial, freshwater, cryospheric
    and coastal and open ocean ecosystems. The extent and magnitude of climate change
    impacts are larger than estimated in previous assessments. Approximately half
    of the species assessed globally have shifted polewards or, on land, also to higher
    elevations. Biological responses including changes in geographic placement and
    shifting seasonal timing are often not sufficient to cope with recent climate
    change. Hundreds of local losses of species have been driven by increases in the
    magnitude of heat extremes and mass mortality events on land and in the ocean.
    Impacts on some ecosystems are approaching irreversibility such as the impacts
    of hydrological changes resulting from the retreat of glaciers, or the changes
    in some mountain and Arctic ecosystems driven by permafrost thaw. Impacts in ecosystems
    from slow-onset processes such as ocean acidification, sea level rise or regional
    decreases in precipitation have also been attributed to human-caused climate change.
    Climate change has contributed to desertification and exacerbated land degradation,
    particularly in low lying coastal areas, river deltas, drylands and in permafrost
    areas. Nearly 50% of coastal wetlands have been lost over the last 100 years,
    as a result of the combined effects of localised human pressures, sea level rise,
    warming and extreme climate events.  Climate change has reduced food security
    and affected water security due to warming, changing precipitation patterns, reduction
    and loss of cryospheric elements, and greater frequency and intensity of climatic
    extremes, thereby hindering efforts to meet Sustainable Development Goals. Although
    overall agricultural productivity has increased, climate change has slowed this
    growth in agricultural productivity over the past 50 years globally , with related
    negative crop yield impacts mainly recorded in mid- and low latitude regions,
    and some positive impacts in some high latitude regions. Ocean warming in the
    20th century and beyond has contributed to an overall decrease in maximum catch
    potential, compounding the impacts from overfishing for some fish stocks. Ocean
    warming and ocean acidification have adversely affected food production from shellfish
    aquaculture and fisheries in some oceanic regions . Current levels of global warming
    are associated with moderate risks from increased dryland water scarcity. Roughly
    half of the world’s population currently experiences severe water scarcity for
    at least some part of the year due to a combination of climatic and non-climatic
    drivers. Unsustainable agricultural expansion, driven in part by unbalanced diets
    , increases ecosystem and human vulnerability and leads to competition for land
    and/or water resources. Increasing weather and climate extreme events have exposed
    millions of people to acute food insecurity and reduced water security, with the
    largest impacts observed in many locations and/or communities in Africa, Asia,
    Central and South America, LDCs, Small Islands and the Arctic, and for small-scale
    food producers, low-income households and Indigenous Peoples globally.  In urban
    settings, climate change has caused adverse impacts on human health, livelihoods
    and key infrastructure. Hot extremes including heatwaves have intensified in cities
    , where they have also worsened air pollution events and limited functioning of
    key infrastructure . Urban infrastructure, including transportation, water, sanitation
    and energy systems have been compromised by extreme and slow-onset events , with
    resulting economic losses, disruptions of services and impacts to well-being.
    Observed impacts are concentrated amongst economically and socially marginalised
    urban residents, e.g., those living in informal settlements. Cities intensify
    human-caused warming locally, while urbanisation also increases mean and heavy
    precipitation over and/or downwind of cities and resulting runoff intensity .  Climate
    change has adversely affected human physical health globally and mental health
    in assessed regions, and is contributing to humanitarian crises where climate
    hazards interact with high vulnerability. In all regions increases in extreme
    heat events have resulted in human mortality and morbidity . The occurrence of
    climate-related food-borne and water-borne diseases has increased. The incidence
    of vector-borne diseases has increased from range expansion and/or increased reproduction
    of disease vectors. Animal and human diseases, including zoonoses, are emerging
    in new areas . In assessed regions, some mental health challenges are associated
    with increasing temperatures, trauma from extreme events, and loss of livelihoods
    and culture . Climate change impacts on health are mediated through natural and
    human systems, including economic and social conditions and disruptions. Climate
    and weather extremes are increasingly driving displacement in Africa, Asia, North
    America, and Central and South America , with small island states in the Caribbean
    and South Pacific being disproportionately affected relative to their small population
    size. Through displacement and involuntary migration from extreme weather and
    climate events, climate change has generated and perpetuated vulnerability .  Human
    influence has likely increased the chance of compound extreme events since the
    1950s. Concurrent and repeated climate hazards have occurred in all regions, increasing
    impacts and risks to health, ecosystems, infrastructure, livelihoods and food
    . Compound extreme events include increases in the frequency of concurrent heatwaves
    and droughts; fire weather in some regions; and compound flooding in some locations.
    Multiple risks interact, generating new sources of vulnerability to climate hazards,
    and compounding overall risk. Compound climate hazards can overwhelm adaptive
    capacity and substantially increase damage ).  Economic impacts attributable to
    climate change are increasingly affecting peoples’ livelihoods and are causing
    economic and societal impacts across national boundaries. Economic damages from
    climate change have been detected in climate-exposed sectors, with regional effects
    to agriculture, forestry, fishery, energy, and tourism, and through outdoor labour
    productivity with some exceptions of positive impacts in regions with low energy
    demand and comparative advantages in agricultural markets and tourism. Individual
    livelihoods have been affected through changes in agricultural productivity, impacts
    on human health and food security, destruction of homes and infrastructure, and
    loss of property and income, with adverse effects on gender and social equity
    . Tropical cyclones have reduced economic growth in the short-term. Event attribution
    studies and physical understanding indicate that human-caused climate change increases
    heavy precipitation associated with tropical cyclones. Wildfires in many regions
    have affected built assets, economic activity, and health. In cities and settlements,
    climate impacts to key infrastructure are leading to losses and damages across
    water and food systems, and affect economic activity, with impacts extending beyond
    the area directly impacted by the climate hazard.  Climate change has caused widespread
    adverse impacts and related losses and damages to nature and people . Losses and
    damages are unequally distributed across systems, regions and sectors. Cultural
    losses, related to tangible and intangible heritage, threaten adaptive capacity
    and may result in irrevocable losses of sense of belonging, valued cultural practices,
    identity and home, particularly for Indigenous Peoples and those more directly
    reliant on the environment for subsistence. For example, changes in snow cover,
    lake and river ice, and permafrost in many Arctic regions, are harming the livelihoods
    and cultural identity of Arctic residents including Indigenous populations. Infrastructure,
    including transportation, water, sanitation and energy systems have been compromised
    by extreme and slow-onset events, with resulting economic losses, disruptions
    of services and impacts to well-being.  Across sectors and regions, the most vulnerable
    people and systems have been disproportionately affected by the impacts of climate
    change. LDCs and SIDS who have much lower per capita emissions than the global
    average excluding CO2-LULUCF, also have high vulnerability to climatic hazards,
    with global hotspots of high human vulnerability observed in West-, Central- and
    East Africa, South Asia, Central and South America, SIDS and the Arctic. Regions
    and people with considerable development constraints have high vulnerability to
    climatic hazards. Vulnerability is higher in locations with poverty, governance
    challenges and limited access to basic services and resources, violent conflict
    and high levels of climate-sensitive livelihoods  . Vulnerability at different
    spatial levels is exacerbated by inequity and marginalisation linked to gender,
    ethnicity, low income or combinations thereof, especially for many Indigenous
    Peoples and local communities. Approximately 3.3 to 3.6 billion people live in
    contexts that are highly vulnerable to climate change. Between 2010 and 2020,
    human mortality from floods, droughts and storms was 15 times higher in highly
    vulnerable regions, compared to regions with very low vulnerability. In the Arctic
    and in some high mountain regions, negative impacts of cryosphere change have
    been especially felt among Indigenous Peoples. Human and ecosystem vulnerability
    are interdependent. Vulnerability of ecosystems and people to climate change differs
    substantially among and within regions, driven by patterns of intersecting socio-economic
    development, unsustainable ocean and land use, inequity, marginalisation, historical
    and ongoing patterns of inequity such as colonialism, and governance.
  - Impacts and Related Risks  For a given level of warming, many climate-related
    risks are assessed to be higher than in AR5. Levels of risk for all Reasons for
    Concern 121 are assessed to become high to very high at lower global warming levels
    compared to what was assessed in AR5. This is based upon recent evidence of observed
    impacts, improved process understanding, and new knowledge on exposure and vulnerability
    of human and natural systems, including limits to adaptation. Depending on the
    level of global warming, the assessed long-term impacts will be up to multiple
    times higher than currently observed for 127 identified key risks, e.g., in terms
    of the number of affected people and species. Risks, including cascading risks
    and risks from overshoot, are projected to become increasingly severe with every
    increment of global warming.  Climate-related risks for natural and human systems
    are higher for global warming of 1.5°C than at present but lower than at 2°C .
    Climate-related risks to health, livelihoods, food security, water supply, human
    security, and economic growth are projected to increase with global warming of
    1.5°C. In terrestrial ecosystems, 3 to 14% of the tens of thousands of species
    assessed will likely face a very high risk of extinction at a GWL of 1.5°C. Coral
    reefs are projected to decline by a further 70–90% at 1.5°C of global warming.
    At this GWL, many low-elevation and small glaciers around the world would lose
    most of their mass or disappear within decades to centuries. Regions at disproportionately
    higher risk include Arctic ecosystems, dryland regions, small island developing
    states and Least Developed Countries .  At 2°C of global warming, overall risk
    levels associated with the unequal distribution of impacts, global aggregate impacts
    and large-scale singular events would be transitioning to high , those associated
    with extreme weather events would be transitioning to very high, and those associated
    with unique and threatened systems would be very high  . With about 2°C warming,
    climate-related changes in food availability and diet quality are estimated to
    increase nutrition-related diseases and the number of undernourished people, affecting
    tens to hundreds of millions of people, particularly among low-income households
    in low- and middle-income countries in sub-Saharan Africa, South Asia and Central
    America. For example, snowmelt water availability for irrigation is projected
    to decline in some snowmelt dependent river basins by up to 20% . Climate change
    risks to cities, settlements and key infrastructure will rise sharply in the mid
    and long term with further global warming, especially in places already exposed
    to high temperatures, along coastlines, or with high vulnerabilities .  At global
    warming of 3°C, additional risks in many sectors and regions reach high or very
    high levels, implying widespread systemic impacts, irreversible change and many
    additional adaptation limits . For example, very high extinction risk for endemic
    species in biodiversity hotspots is projected to increase at least tenfold if
    warming rises from 1.5°C to 3°C. Projected increases in direct flood damages are
    higher by 1.4 to 2 times at 2°C and 2.5 to 3.9 times at 3°C, compared to 1.5°C
    global warming without adaptation.  Global warming of 4°C and above is projected
    to lead to far-reaching impacts on natural and human systems. Beyond 4°C of warming,
    projected impacts on natural systems include local extinction of ~50% of tropical
    marine species and biome shifts across 35% of global land area. At this level
    of warming, approximately 10% of the global land area is projected to face both
    increasing high and decreasing low extreme streamflow, affecting, without additional
    adaptation, over 2.1 billion people and about 4 billion people are projected to
    experience water scarcity. At 4°C of warming, the global burned area is projected
    to increase by 50 to 70% and the fire frequency by ~30% compared to today.  Projected
    adverse impacts and related losses and damages from climate change escalate with
    every increment of global warming , but they will also strongly depend on socio-economic
    development trajectories and adaptation actions to reduce vulnerability and exposure.
    For example, development pathways with higher demand for food, animal feed, and
    water, more resource-intensive consumption and production, and limited technological
    improvements result in higher risks from water scarcity in drylands, land degradation
    and food insecurity . Changes in, for example, demography or investments in health
    systems have effect on a variety of health-related outcomes including heat-related
    morbidity and mortality.  With every increment of warming, climate change impacts
    and risks will become increasingly complex and more difficult to manage. Many
    regions are projected to experience an increase in the probability of compound
    events with higher global warming, such as concurrent heatwaves and droughts,
    compound flooding and fire weather. In addition, multiple climatic and non-climatic
    risk drivers such as biodiversity loss or violent conflict will interact, resulting
    in compounding overall risk and risks cascading across sectors and regions. Furthermore,
    risks can arise from some responses that are intended to reduce the risks of climate
    change, e.g., adverse side effects of some emission reduction and carbon dioxide
    removal measures .  Solar Radiation Modification approaches, if they were to be
    implemented, introduce a widespread range of new risks to people and ecosystems,
    which are not well understood. SRM has the potential to offset warming within
    one or two decades and ameliorate some climate hazards but would not restore climate
    to a previous state, and substantial residual or overcompensating climate change
    would occur at regional and seasonal scales. Effects of SRM would depend on the
    specific approach used 122, and a sudden and sustained termination of SRM in a
    high CO 2 emissions scenario would cause rapid climate change. SRM would not stop
    atmospheric CO 2 concentrations from increasing nor reduce resulting ocean acidification
    under continued anthropogenic emissions. Large uncertainties and knowledge gaps
    are associated with the potential of SRM approaches to reduce climate change risks.
    Lack of robust and formal SRM governance poses risks as deployment by a limited
    number of states could create international tensions.
  - Long-term Adaptation Options and Limits  With increasing warming, adaptation options
    will become more constrained and less effective. At higher levels of warming,
    losses and damages will increase, and additional human and natural systems will
    reach adaptation limits. Integrated, cross-cutting multi-sectoral solutions increase
    the effectiveness of adaptation. Maladaptation can create lock-ins of vulnerability,
    exposure and risks but can be avoided by long-term planning and the implementation
    of adaptation actions that are flexible, multi-sectoral and inclusive. The effectiveness
    of adaptation to reduce climate risk is documented for specific contexts, sectors
    and regions and will decrease with increasing warming 125 . For example, common
    adaptation responses in agriculture – adopting improved cultivars and agronomic
    practices, and changes in cropping patterns and crop systems – will become less
    effective from 2°C to higher levels of warming. The effectiveness of most water-related
    adaptation options to reduce projected risks declines with increasing warming.
    Adaptations for hydropower and thermo-electric power generation are effective
    in most regions up to 1.5°C to 2°C, with decreasing effectiveness at higher levels
    of warming . Ecosystem-based Adaptation is vulnerable to climate change impacts,
    with effectiveness declining with increasing global warming. Globally, adaptation
    options related to agroforestry and forestry have a sharp decline in effectiveness
    at 3°C, with a substantial increase in residual risk.  With increasing global
    warming, more limits to adaptation will be reached and losses and damages, strongly
    concentrated among the poorest vulnerable populations, will increase. Already
    below 1.5°C, autonomous and evolutionary adaptation responses by terrestrial and
    aquatic ecosystems will increasingly face hard limits. Above 1.5°C, some ecosystem-based
    adaptation measures will lose their effectiveness in providing benefits to people
    as these ecosystems will reach hard adaptation limits. Adaptation to address the
    risks of heat stress, heat mortality and reduced capacities for outdoor work for
    humans face soft and hard limits across regions that become significantly more
    severe at 1.5°C, and are particularly relevant for regions with warm climates.
    Above 1.5°C global warming level, limited freshwater resources pose potential
    hard limits for small islands and for regions dependent on glacier and snow melt
    . By 2°C, soft limits are projected for multiple staple crops, particularly in
    tropical regions. By 3°C, soft limits are projected for some water management
    measures for many regions, with hard limits projected for parts of Europe .  Integrated,
    cross-cutting multi-sectoral solutions increase the effectiveness of adaptation.
    For example, inclusive, integrated and long-term planning at local, municipal,
    sub-national and national scales, together with effective regulation and monitoring
    systems and financial and technological resources and capabilities foster urban
    and rural system transition. There are a range of cross-cutting adaptation options,
    such as disaster risk management, early warning systems, climate services and
    risk spreading and sharing that have broad applicability across sectors and provide
    greater benefits to other adaptation options when combined. Transitioning from
    incremental to transformational adaptation, and addressing a range of constraints,
    primarily in the financial, governance, institutional and policy domains, can
    help overcome soft adaptation limits. However, adaptation does not prevent all
    losses and damages, even with effective adaptation and before reaching soft and
    hard limits.  Maladaptive responses to climate change can create lock-ins of vulnerability,
    exposure and risks that are difficult and expensive to change and exacerbate existing
    inequalities. Actions that focus on sectors and risks in isolation and on short-term
    gains often lead to maladaptation. Adaptation options can become maladaptive due
    to their environmental impacts that constrain ecosystem services and decrease
    biodiversity and ecosystem resilience to climate change or by causing adverse
    outcomes for different groups, exacerbating inequity. Maladaptation can be avoided
    by flexible, multi-sectoral, inclusive and long-term planning and implementation
    of adaptation actions with benefits to many sectors and systems.  Sea level rise
    poses a distinctive and severe adaptation challenge as it implies both dealing
    with slow onset changes and increases in the frequency and magnitude of extreme
    sea level events . Such adaptation challenges would occur much earlier under high
    rates of sea level rise. Responses to ongoing sea level rise and land subsidence
    include protection, accommodation, advance and planned relocation. These responses
    are more effective if combined and/or sequenced, planned well ahead, aligned with
    sociocultural values and underpinned by inclusive community engagement processes.
    Ecosystem-based solutions such as wetlands provide co-benefits for the environment
    and climate mitigation, and reduce costs for flood defences , but have site-specific
    physical limits, at least above 1.5ºC of global warming and lose effectiveness
    at high rates of sea level rise beyond 0.5 to 1 cm yr -1. Seawalls can be maladaptive
    as they effectively reduce impacts in the short term but can also result in lock-ins
    and increase exposure to climate risks in the long term unless they are integrated
    into a long-term adaptive plan.
  - Remaining Carbon Budgets  Limiting global temperature increase to a specific level
    requires limiting cumulative net CO2 emissions to within a finite carbon budget
    , along with strong reductions in other GHGs. For every 1000 GtCO2 emitted by
    human activity, global mean temperature rises by likely 0.27°C to 0.63°C. This
    relationship implies that there is a finite carbon budget that cannot be exceeded
    in order to limit warming to any given level.  The best estimates of the remaining
    carbon budget from the beginning of 2020 for limiting warming to 1.5°C with a
    50% likelihood is estimated to be 500 GtCO2; for 2°C this is 1150 GtCO2.128 Remaining
    carbon budgets have been quantified based on the assessed value of TCRE and its
    uncertainty, estimates of historical warming, climate system feedbacks such as
    emissions from thawing permafrost, and the global surface temperature change after
    global anthropogenic CO 2 emissions reach net zero, as well as variations in projected
    warming from non-CO2 emissions due in part to mitigation action. The stronger
    the reductions in non-CO2 emissions the lower the resulting temperatures are for
    a given RCB or the larger RCB for the same level of temperature change. For instance,
    the RCB for limiting warming to 1.5°C with a 50% likelihood could vary between
    300 to 600 GtCO 2 depending on non-CO 2 warming 129 . Limiting warming to 2°C
    with a 67% likelihood would imply a RCB of 1150 GtCO2 from the beginning of 2020.
    To stay below 2°C with a 50% likelihood, the RCB is higher, i.e., 1350 GtCO 2
    If the annual CO2 emissions between 2020–2030 stayed, on average, at the same
    level as 2019, the resulting cumulative emissions would almost exhaust the remaining
    carbon budget for 1.5°C, and exhaust more than a third of the remaining carbon
    budget for 2°C . Based on central estimates only, historical cumulative net CO2
    emissions between 1850 and 2019 amount to about four-fifths of the total carbon
    budget for a 50% probability of limiting global warming to 1.5°C and to about
    two-thirds of the total carbon budget for a 67% probability to limit global warming
    to 2°C.  In scenarios with increasing CO 2 emissions, the land and ocean carbon
    sinks are projected to be less effective at slowing the accumulation of CO2 in
    the atmosphere. While natural land and ocean carbon sinks are projected to take
    up, in absolute terms, a progressively larger amount of CO 2 under higher compared
    to lower CO2 emissions scenarios, they become less effective, that is, the proportion
    of emissions taken up by land and ocean decreases with increasing cumulative net
    CO2 emissions. Additional ecosystem responses to warming not yet fully included
    in climate models, such as GHG fluxes from wetlands, permafrost thaw, and wildfires,
    would further increase concentrations of these gases in the atmosphere . In scenarios
    where CO2 concentrations peak and decline during the 21st century, the land and
    ocean begin to take up less carbon in response to declining atmospheric CO2 concentrations  and
    turn into a weak net source by 2100 in the very low GHG emissions scenario 133.
  - 'Sectoral Contributions to Mitigation  All global modelled pathways that limit
    warming to 2°C or lower by 2100 involve rapid and deep and in most cases immediate
    GHG emissions reductions in all sectors. Reductions in GHG emissions in industry,
    transport, buildings, and urban areas can be achieved through a combination of
    energy efficiency and conservation and a transition to low-GHG technologies and
    energy carriers. Socio-cultural options and behavioural change can reduce global
    GHG emissions of end-use sectors, with most of the potential in developed countries,
    if combined with improved infrastructure design and access.  Global modelled mitigation
    pathways reaching net zero CO2 and GHG emissions include transitioning from fossil
    fuels without carbon capture and storage to very low- or zero-carbon energy sources,
    such as renewables or fossil fuels with CCS, demand-side measures and improving
    efficiency, reducing non-CO2 GHG emissions, and CDR 136. In global modelled pathways
    that limit warming to 2°C or below, almost all electricity is supplied from zero
    or low-carbon sources in 2050, such as renewables or fossil fuels with CO2 capture
    and storage, combined with increased electrification of energy demand. Such pathways
    meet energy service demand with relatively low energy use, through e.g., enhanced
    energy efficiency and behavioural changes and increased electrification of energy
    end use. Modelled global pathways limiting global warming to 1.5°C with no or
    limited overshoot generally implement such changes faster than pathways limiting
    global warming to 2°C.  AFOLU mitigation options, when sustainably implemented,
    can deliver large-scale GHG emission reductions and enhanced CO2 removal; however,
    barriers to implementation and trade-offs may result from the impacts of climate
    change, competing demands on land, conflicts with food security and livelihoods,
    the complexity of land ownership and management systems, and cultural aspects.
    All assessed modelled pathways that limit warming to 2°C or lower by 2100 include
    land-based mitigation and land-use change, with most including different combinations
    of reforestation, afforestation, reduced deforestation, and bioenergy. However,
    accumulated carbon in vegetation and soils is at risk from future loss triggered
    by climate change and disturbances such as flood, drought, fire, or pest outbreaks,
    or future poor management.  In addition to deep, rapid, and sustained emission
    reductions, CDR can fulfil three complementary roles: lowering net CO2 or net
    GHG emissions in the near term; counterbalancing ‘hard-to-abate’ residual emissions  to
    help reach net zero CO2 or GHG emissions, and achieving net negative CO 2 or GHG
    emissions if deployed at levels exceeding annual residual emissions. CDR methods
    vary in terms of their maturity, removal process, time scale of carbon storage,
    storage medium, mitigation potential, cost, co-benefits, impacts and risks, and
    governance requirements. Specifically, maturity ranges from lower maturity to
    higher maturity; removal and storage potential ranges from lower potential to
    higher potential; costs range from lower cost to higher cost  . Estimated storage
    timescales vary from decades to centuries for methods that store carbon in vegetation
    and through soil carbon management, to ten thousand years or more for methods
    that store carbon in geological formations . Afforestation, reforestation, improved
    forest management, agroforestry and soil carbon sequestration are currently the
    only widely practiced CDR methods. Methods and levels of CDR deployment in global
    modelled mitigation pathways vary depending on assumptions about costs, availability
    and constraints.'
  - 'The Timing and Urgency of Climate Action  The magnitude and rate of climate change
    and associated risks depend strongly on near-term mitigation and adaptation actions
    . Global warming is more likely than not to reach 1.5°C between 2021 and 2040
    even under the very low GHG emission scenarios, and likely or very likely to exceed
    1.5°C under higher emissions scenarios 141. Many adaptation options have medium
    or high feasibility up to 1.5°C , but hard limits to adaptation have already been
    reached in some ecosystems and the effectiveness of adaptation to reduce climate
    risk will decrease with increasing warming. Societal choices and actions implemented
    in this decade determine the extent to which medium- and long-term pathways will
    deliver higher or lower climate resilient development. Climate resilient development
    prospects are increasingly limited if current greenhouse gas emissions do not
    rapidly decline, especially if 1.5°C global warming is exceeded in the near term.
    Without urgent, effective and equitable adaptation and mitigation actions, climate
    change increasingly threatens the health and livelihoods of people around the
    globe, ecosystem health, and biodiversity, with severe adverse consequences for
    current and future generations. .  In modelled pathways that limit warming to
    1.5°C with no or limited overshoot and in those that limit warming to 2°C, assuming
    immediate actions, global GHG emissions are projected to peak in the early 2020s
    followed by rapid and deep GHG emissions reductions 142 . In pathways that limit
    warming to 1.5°C with no or limited overshoot, net global GHG emissions are projected
    to fall by 43 [34 to 60]%143 below 2019 levels by 2030, 60 [49 to 77]% by 2035,
    69 [58 to 90]% by 2040 and 84 [73 to 98]% by 2050 144. Global modelled pathways
    that limit warming to 2°C have reductions in GHG emissions below 2019 levels of
    21 [1 to 42]% by 2030, 35 [22 to 55] % by 2035, 46 [34 to 63] % by 2040 and 64
    [53 to 77]% by 2050145. Global GHG emissions associated with NDCs announced prior
    to COP26 would make it likely that warming would exceed 1.5°C and limiting warming
    to 2°C would then imply a rapid acceleration of emission reductions during 2030–2050,
    around 70% faster than in pathways where immediate action is taken to limit warming
    to 2°C Continued investments in unabated high-emitting infrastructure and limited
    development and deployment of low-emitting alternatives prior to 2030 would act
    as barriers to this acceleration and increase feasibility risks.  All global modelled
    pathways that limit warming to 2°C or lower by 2100 involve reductions in both
    net CO 2 emissions and non-CO 2 emissions. For example, in pathways that limit
    warming to 1.5°C with no or limited overshoot, global CH4 emissions are reduced
    by 34 [21 to 57]% below 2019 levels by 2030 and by 44 [31 to 63]% in 2040. Global
    CH 4 emissions are reduced by 24 [9 to 53]% below 2019 levels by 2030 and by 37
    [20 to 60]% in 2040 in modelled pathways that limit warming to 2°C with action
    starting in 2020.  All global modelled pathways that limit warming to 2°C or lower
    by 2100 involve GHG emission reductions in all sectors . The contributions of
    different sectors vary across modelled mitigation pathways. In most global modelled
    mitigation pathways, emissions from land-use, land-use change and forestry, via
    reforestation and reduced deforestation, and from the energy supply sector reach
    net zero CO2 emissions earlier than the buildings, industry and transport sectors.
    Strategies can rely on combinations of different options, but doing less in one
    sector needs to be compensated by further reductions in other sectors if warming
    is to be limited.  Without rapid, deep and sustained mitigation and accelerated
    adaptation actions, losses and damages will continue to increase, including projected
    adverse impacts in Africa, LDCs, SIDS, Central and South America , Asia and the
    Arctic, and will disproportionately affect the most vulnerable populations .  '
  - 'Benefits of Strengthening Near-Term Action  Accelerated implementation of adaptation
    will improve well-being by reducing losses and damages, especially for vulnerable
    populations. Deep, rapid, and sustained mitigation actions would reduce future
    adaptation costs and losses and damages, enhance sustainable development co-benefits,
    avoid locking-in emission sources, and reduce stranded assets and irreversible
    climate changes. These near-term actions involve higher up-front investments and
    disruptive changes, which can be moderated by a range of enabling conditions and
    removal or reduction of barriers to feasibility. Accelerated implementation of
    adaptation responses will bring benefits to human well-being. As adaptation options
    often have long implementation times, long-term planning and accelerated implementation,
    particularly in this decade, is important to close adaptation gaps, recognising
    that constraints remain for some regions. The benefits to vulnerable populations
    would be high .  Near-term actions that limit global warming to close to 1.5°C
    would substantially reduce projected losses and damages related to climate change
    in human systems and ecosystems, compared to higher warming levels, but cannot
    eliminate them all . The magnitude and rate of climate change and associated risks
    depend strongly on near-term mitigation and adaptation actions, and projected
    adverse impacts and related losses and damages escalate with every increment of
    global warming. Delayed mitigation action will further increase global warming
    which will decrease the effectiveness of many adaptation options, including Ecosystem-based
    Adaptation and many water-related options, as well as increasing mitigation feasibility
    risks, such as for options based on ecosystems. Comprehensive, effective, and
    innovative responses integrating adaptation and mitigation can harness synergies
    and reduce trade-offs between adaptation and mitigation, as well as in meeting
    requirements for financing .  Mitigation actions will have other sustainable development
    co-benefits. Mitigation will improve air quality and human health in the near
    term notably because many air pollutants are co-emitted by GHG emitting sectors
    and because methane emissions leads to surface ozone formation. The benefits from
    air quality improvement include prevention of air pollution-related premature
    deaths, chronic diseases and damages to ecosystems and crops. The economic benefits
    for human health from air quality improvement arising from mitigation action can
    be of the same order of magnitude as mitigation costs, and potentially even larger
    . As methane has a short lifetime but is a potent GHG, strong, rapid and sustained
    reductions in methane emissions can limit near-term warming and improve air quality
    by reducing global surface ozone.  Challenges from delayed adaptation and mitigation
    actions include the risk of cost escalation, lock-in of infrastructure, stranded
    assets, and reduced feasibility and effectiveness of adaptation and mitigation
    options. The continued installation of unabated fossil fuel infrastructure will
    ‘lock-in’ GHG emissions. Limiting global warming to 2°C or below will leave a
    substantial amount of fossil fuels unburned and could strand considerable fossil
    fuel infrastructure , with globally discounted value projected to be around USD
    1 to 4 trillion from 2015 to 2050. Early actions would limit the size of these
    stranded assets, whereas delayed actions with continued investments in unabated
    high-emitting infrastructure and limited development and deployment of low-emitting
    alternatives prior to 2030 would raise future stranded assets to the higher end
    of the range – thereby acting as barriers and increasing political economy feasibility
    risks that may jeopardise efforts to limit global warming. .  Scaling-up near-term
    climate actions will mobilise a mix of low-cost and high-cost options. High-cost
    options, as in energy and infrastructure, are needed to avoid future lock-ins,
    foster innovation and initiate transformational changes. Climate resilient development
    pathways in support of sustainable development for all are shaped by equity, and
    social and climate justice. Embedding effective and equitable adaptation and mitigation
    in development planning can reduce vulnerability, conserve and restore ecosystems,
    and enable climate resilient development. This is especially challenging in localities
    with persistent development gaps and limited resources.  Scaling-up climate action
    may generate disruptive changes in economic structure with distributional consequences
    and need to reconcile divergent interests, values and worldviews, within and between
    countries. Deeper fiscal, financial, institutional and regulatory reforms can
    offset such adverse effects and unlock mitigation potentials. Societal choices
    and actions implemented in this decade will determine the extent to which medium
    and long-term development pathways will deliver higher or lower climate resilient
    development outcomes.  Enabling conditions would need to be strengthened in the
    nearterm and barriers reduced or removed to realise opportunities for deep and
    rapid adaptation and mitigation actions and climate resilient development. These
    enabling conditions are differentiated by national, regional and local circumstances
    and geographies, according to capabilities, and include: equity and inclusion
    in climate action, rapid and far-reaching transitions in sectors and system ,
    measures to achieve synergies and reduce tradeoffs with sustainable development
    goals, governance and policy improvements, access to finance, improved international
    cooperation and technology improvements, and integration of near-term actions
    across sectors, systems and regions.  Barriers to feasibility would need to be
    reduced or removed to deploy mitigation and adaptation options at scale. Many
    limits to feasibility and effectiveness of responses can be overcome by addressing
    a range of barriers, including economic, technological, institutional, social,
    environmental and geophysical barriers. The feasibility and effectiveness of options
    increase with integrated, multi-sectoral solutions that differentiate responses
    based on climate risk, cut across systems and address social inequities. Strengthened
    near-term actions in modelled cost-effective pathways that limit global warming
    to 2°C or lower, reduce the overall risk to the feasibility of the system transitions,
    compared to modelled pathways with delayed or uncoordinated action.  Integrating
    ambitious climate actions with macroeconomic policies under global uncertainty
    would provide benefits . This encompasses three main directions: economy-wide
    mainstreaming packages supporting options to improved sustainable low-emission
    economic recovery, development and job creation programs  safety nets and social
    protection in the transition; and broadened access to finance, technology and
    capacity-building and coordinated support to low-emission infrastructure , especially
    in developing regions, and under debt stress .'
  - 'Near-Term Risks  Many changes in the climate system, including extreme events,
    will become larger in the near term with increasing global warming. Multiple climatic
    and non-climatic risks will interact, resulting in increased compounding and cascading
    impacts becoming more difficult to manage. Losses and damages will increase with
    increasing global warming, while strongly concentrated among the poorest vulnerable
    populations. Continuing with current unsustainable development patterns would
    increase exposure and vulnerability of ecosystems and people to climate hazards.
    Global warming will continue to increase in the near term mainly due to increased
    cumulative CO 2 emissions in nearly all considered scenarios and pathways. In
    the near term, every region in the world is projected to face further increases
    in climate hazards , increasing multiple risks to ecosystems and humans. In the
    near term, natural variability will modulate human-caused changes, either attenuating
    or amplifying projected changes, especially at regional scales, with little effect
    on centennial global warming. Those modulations are important to consider in adaptation
    planning. Global surface temperature in any single year can vary above or below
    the long-term human-induced trend, due to natural variability. By 2030, global
    surface temperature in any individual year could exceed 1.5°C relative to 1850–1900
    with a probability between 40% and 60%, across the five scenarios assessed in
    WGI. The occurrence of individual years with global surface temperature change
    above a certain level does not imply that this global warming level has been reached.
    If a large explosive volcanic eruption were to occur in the near term 150, it
    would temporarily and partially mask human-caused climate change by reducing global
    surface temperature and precipitation, especially over land, for one to three
    years.  The level of risk for humans and ecosystems will depend on near-term trends
    in vulnerability, exposure, level of socio-economic development and adaptation.
    In the near term, many climate-associated risks to natural and human systems depend
    more strongly on changes in these systems’ vulnerability and exposure than on
    differences in climate hazards between emissions scenarios . Future exposure to
    climatic hazards is increasing globally due to socio-economic development trends
    including growing inequality, and when urbanisation or migration increase exposure
    . Urbanisation increases hot extremes  and precipitation runoff intensity. Increasing
    urbanisation in low-lying and coastal zones will be a major driver of increasing
    exposure to extreme riverflow events and sea level rise hazards, increasing risks.
    Vulnerability will also rise rapidly in low-lying Small Island Developing States
    and atolls in the context of sea level rise . Human vulnerability will concentrate
    in informal settlements and rapidly growing smaller settlements; and vulnerability
    in rural areas will be heightened by reduced habitability and high reliance on
    climate-sensitive livelihoods. Human and ecosystem vulnerability are interdependent.
    Vulnerability to climate change for ecosystems will be strongly influenced by
    past, present, and future patterns of human development, including from unsustainable
    consumption and production, increasing demographic pressures, and persistent unsustainable
    use and management of land, ocean, and water. Several near-term risks can be moderated
    with adaptation.  Principal hazards and associated risks expected in the near
    term are: • Increased intensity and frequency of hot extremes and dangerous heat-humidity
    conditions, with increased human mortality, morbidity, and labour productivity
    loss.  • Increasing frequency of marine heatwaves will increase risks of biodiversity
    loss in the oceans, including from mass mortality events.  • Near-term risks for
    biodiversity loss are moderate to high in forest ecosystems and kelp and seagrass
    ecosystems and are high to very high in Arctic sea-ice and terrestrial ecosystems
    and warm-water coral reefs.  • More intense and frequent extreme rainfall and
    associated flooding in many regions including coastal and other low-lying cities
    , and increased proportion of and peak wind speeds of intense tropical cyclones.  •
    High risks from dryland water scarcity, wildfire damage, and permafrost degradation.  •
    Continued sea level rise and increased frequency and magnitude of extreme sea
    level events encroaching on coastal human settlements and damaging coastal infrastructure
    , committing low-lying coastal ecosystems to submergence and loss, expanding land
    salinization, with cascading to risks to livelihoods, health, well-being, cultural
    values, food and water security.  • Climate change will significantly increase
    ill health and premature deaths from the near to long term. Further warming will
    increase climate-sensitive food-borne, water-borne, and vector-borne disease risks,
    and mental health challenges including anxiety and stress.  Cryosphere-related
    changes in floods, landslides, and water availability have the potential to lead
    to severe consequences for people, infrastructure and the economy in most mountain
    regions .  • The projected increase in frequency and intensity of heavy precipitation
    will increase rain-generated local flooding.  Multiple climate change risks will
    increasingly compound and cascade in the near term. Many regions are projected
    to experience an increase in the probability of compound events with higher global
    warming including concurrent heatwaves and drought. Risks to health and food production
    will be made more severe from the interaction of sudden food production losses
    from heat and drought, exacerbated by heatinduced labour productivity losses.
    These interacting impacts will increase food prices, reduce household incomes,
    and lead to health risks of malnutrition and climate-related mortality with no
    or low levels of adaptation, especially in tropical regions . Concurrent and cascading
    risks from climate change to food systems, human settlements, infrastructure and
    health will make these risks more severe and more difficult to manage, including
    when interacting with non-climatic risk drivers such as competition for land between
    urban expansion and food production, and pandemics . Loss of ecosystems and their
    services has cascading and long-term impacts on people globally, especially for
    Indigenous Peoples and local communities who are directly dependent on ecosystems,
    to meet basic needs. Increasing transboundary risks are projected across the food,
    energy and water sectors as impacts from weather and climate extremes propagate
    through supply-chains, markets, and natural resource flows and may interact with
    impacts from other crises such as pandemics. Risks also arise from some responses
    intended to reduce the risks of climate change, including risks from maladaptation
    and adverse side effects of some emissions reduction and carbon dioxide removal
    measures, such as afforestation of naturally unforested land or poorly implemented
    bioenergy compounding climate-related risks to biodiversity, food and water security,
    and livelihoods.  With every increment of global warming losses and damages will
    increase, become increasingly difficult to avoid and be strongly concentrated
    among the poorest vulnerable populations. Adaptation does not prevent all losses
    and damages, even with effective adaptation and before reaching soft and hard
    limits. Losses and damages will be unequally distributed across systems, regions
    and sectors and are not comprehensively addressed by current financial, governance
    and institutional arrangements, particularly in vulnerable developing countries.
    .'
  C.2.3:
  - 'Benefits of Strengthening Near-Term Action  Accelerated implementation of adaptation
    will improve well-being by reducing losses and damages, especially for vulnerable
    populations. Deep, rapid, and sustained mitigation actions would reduce future
    adaptation costs and losses and damages, enhance sustainable development co-benefits,
    avoid locking-in emission sources, and reduce stranded assets and irreversible
    climate changes. These near-term actions involve higher up-front investments and
    disruptive changes, which can be moderated by a range of enabling conditions and
    removal or reduction of barriers to feasibility. Accelerated implementation of
    adaptation responses will bring benefits to human well-being. As adaptation options
    often have long implementation times, long-term planning and accelerated implementation,
    particularly in this decade, is important to close adaptation gaps, recognising
    that constraints remain for some regions. The benefits to vulnerable populations
    would be high .  Near-term actions that limit global warming to close to 1.5°C
    would substantially reduce projected losses and damages related to climate change
    in human systems and ecosystems, compared to higher warming levels, but cannot
    eliminate them all . The magnitude and rate of climate change and associated risks
    depend strongly on near-term mitigation and adaptation actions, and projected
    adverse impacts and related losses and damages escalate with every increment of
    global warming. Delayed mitigation action will further increase global warming
    which will decrease the effectiveness of many adaptation options, including Ecosystem-based
    Adaptation and many water-related options, as well as increasing mitigation feasibility
    risks, such as for options based on ecosystems. Comprehensive, effective, and
    innovative responses integrating adaptation and mitigation can harness synergies
    and reduce trade-offs between adaptation and mitigation, as well as in meeting
    requirements for financing .  Mitigation actions will have other sustainable development
    co-benefits. Mitigation will improve air quality and human health in the near
    term notably because many air pollutants are co-emitted by GHG emitting sectors
    and because methane emissions leads to surface ozone formation. The benefits from
    air quality improvement include prevention of air pollution-related premature
    deaths, chronic diseases and damages to ecosystems and crops. The economic benefits
    for human health from air quality improvement arising from mitigation action can
    be of the same order of magnitude as mitigation costs, and potentially even larger
    . As methane has a short lifetime but is a potent GHG, strong, rapid and sustained
    reductions in methane emissions can limit near-term warming and improve air quality
    by reducing global surface ozone.  Challenges from delayed adaptation and mitigation
    actions include the risk of cost escalation, lock-in of infrastructure, stranded
    assets, and reduced feasibility and effectiveness of adaptation and mitigation
    options. The continued installation of unabated fossil fuel infrastructure will
    ‘lock-in’ GHG emissions. Limiting global warming to 2°C or below will leave a
    substantial amount of fossil fuels unburned and could strand considerable fossil
    fuel infrastructure , with globally discounted value projected to be around USD
    1 to 4 trillion from 2015 to 2050. Early actions would limit the size of these
    stranded assets, whereas delayed actions with continued investments in unabated
    high-emitting infrastructure and limited development and deployment of low-emitting
    alternatives prior to 2030 would raise future stranded assets to the higher end
    of the range – thereby acting as barriers and increasing political economy feasibility
    risks that may jeopardise efforts to limit global warming. .  Scaling-up near-term
    climate actions will mobilise a mix of low-cost and high-cost options. High-cost
    options, as in energy and infrastructure, are needed to avoid future lock-ins,
    foster innovation and initiate transformational changes. Climate resilient development
    pathways in support of sustainable development for all are shaped by equity, and
    social and climate justice. Embedding effective and equitable adaptation and mitigation
    in development planning can reduce vulnerability, conserve and restore ecosystems,
    and enable climate resilient development. This is especially challenging in localities
    with persistent development gaps and limited resources.  Scaling-up climate action
    may generate disruptive changes in economic structure with distributional consequences
    and need to reconcile divergent interests, values and worldviews, within and between
    countries. Deeper fiscal, financial, institutional and regulatory reforms can
    offset such adverse effects and unlock mitigation potentials. Societal choices
    and actions implemented in this decade will determine the extent to which medium
    and long-term development pathways will deliver higher or lower climate resilient
    development outcomes.  Enabling conditions would need to be strengthened in the
    nearterm and barriers reduced or removed to realise opportunities for deep and
    rapid adaptation and mitigation actions and climate resilient development. These
    enabling conditions are differentiated by national, regional and local circumstances
    and geographies, according to capabilities, and include: equity and inclusion
    in climate action, rapid and far-reaching transitions in sectors and system ,
    measures to achieve synergies and reduce tradeoffs with sustainable development
    goals, governance and policy improvements, access to finance, improved international
    cooperation and technology improvements, and integration of near-term actions
    across sectors, systems and regions.  Barriers to feasibility would need to be
    reduced or removed to deploy mitigation and adaptation options at scale. Many
    limits to feasibility and effectiveness of responses can be overcome by addressing
    a range of barriers, including economic, technological, institutional, social,
    environmental and geophysical barriers. The feasibility and effectiveness of options
    increase with integrated, multi-sectoral solutions that differentiate responses
    based on climate risk, cut across systems and address social inequities. Strengthened
    near-term actions in modelled cost-effective pathways that limit global warming
    to 2°C or lower, reduce the overall risk to the feasibility of the system transitions,
    compared to modelled pathways with delayed or uncoordinated action.  Integrating
    ambitious climate actions with macroeconomic policies under global uncertainty
    would provide benefits . This encompasses three main directions: economy-wide
    mainstreaming packages supporting options to improved sustainable low-emission
    economic recovery, development and job creation programs  safety nets and social
    protection in the transition; and broadened access to finance, technology and
    capacity-building and coordinated support to low-emission infrastructure , especially
    in developing regions, and under debt stress .'
  - Land, Ocean, Food, and Water  There is substantial mitigation and adaptation potential
    from options in agriculture, forestry and other land use, and in the oceans, that
    could be upscaled in the near term across most regions. Conservation, improved
    management, and restoration of forests and other ecosystems offer the largest
    share of economic mitigation potential, with reduced deforestation in tropical
    regions having the highest total mitigation potential. Ecosystem restoration,
    reforestation, and afforestation can lead to trade-offs due to competing demands
    on land. Minimizing trade-offs requires integrated approaches to meet multiple
    objectives including food security. Demand-side measures  and sustainable agricultural
    intensification can reduce ecosystem conversion and CH4 and N2 O emissions, and
    free up land for reforestation and ecosystem restoration. Sustainably sourced
    agriculture and forest products, including long-lived wood products, can be used
    instead of more GHG-intensive products in other sectors. Effective adaptation
    options include cultivar improvements, agroforestry, community-based adaptation,
    farm and landscape diversification, and urban agriculture. These AFOLU response
    options require integration of biophysical, socioeconomic and other enabling factors.
    The effectiveness of ecosystem-based adaptation and most water-related adaptation
    options declines with increasing warming.  Some options, such as conservation
    of high-carbon ecosystems , have immediate impacts while others, such as restoration
    of high-carbon ecosystems, reclamation of degraded soils or afforestation, take
    decades to deliver measurable results. Many sustainable land management technologies
    and practices are financially profitable in three to ten years.  Maintaining the
    resilience of biodiversity and ecosystem services at a global scale depends on
    effective and equitable conservation of approximately 30–50% of Earth’s land,
    freshwater and ocean areas, including currently near-natural ecosystems. The services
    and options provided by terrestrial, freshwater, coastal and ocean ecosystems
    can be supported by protection, restoration, precautionary ecosystem-based management
    of renewable resource use, and the reduction of pollution and other stressors.  Large-scale
    land conversion for bioenergy, biochar, or afforestation can increase risks to
    biodiversity, water and food security. In contrast, restoring natural forests
    and drained peatlands, and improving sustainability of managed forests enhances
    the resilience of carbon stocks and sinks and reduces ecosystem vulnerability
    to climate change. Cooperation, and inclusive decision making, with local communities
    and Indigenous Peoples, as well as recognition of inherent rights of Indigenous
    Peoples, is integral to successful adaptation across forests and other ecosystems.  Natural
    rivers, wetlands and upstream forests reduce flood risk in most circumstances.
    Enhancing natural water retention such as by restoring wetlands and rivers, land
    use planning such as no build zones or upstream forest management, can further
    reduce flood risk . For inland flooding, combinations of non-structural measures
    like early warning systems and structural measures like levees have reduced loss
    of lives, but hard defences against flooding or sea level rise can also be maladaptive
    .  Protection and restoration of coastal ‘blue carbon’ ecosystems could reduce
    emissions and/or increase carbon uptake and storage . Coastal wetlands protect
    against coastal erosion and flooding. Strengthening precautionary approaches,
    such as rebuilding overexploited or depleted fisheries, and responsiveness of
    existing fisheries management strategies reduces negative climate change impacts
    on fisheries, with benefits for regional economies and livelihoods. Ecosystem-based
    management in fisheries and aquaculture supports food security, biodiversity,
    human health and well-being.
  - Health and Nutrition  Human health will benefit from integrated mitigation and
    adaptation options that mainstream health into food, infrastructure, social protection,
    and water policies . Balanced and sustainable healthy diets and reduced food loss
    and waste present important opportunities for adaptation and mitigation while
    generating significant co-benefits in terms of biodiversity and human health.
    Public health policies to improve nutrition, such as increasing the diversity
    of food sources in public procurement, health insurance, financial incentives,
    and awareness-raising campaigns, can potentially influence food demand, reduce
    food waste, reduce healthcare costs, contribute to lower GHG emissions and enhance
    adaptive capacity. Improved access to clean energy sources and technologies, and
    shifts to active mobility and public transport can deliver socioeconomic, air
    quality and health benefits, especially for women and children.  Effective adaptation
    options exist to help protect human health and well-being. Health Action Plans
    that include early warning and response systems are effective for extreme heat
    . Effective options for water-borne and food-borne diseases include improving
    access to potable water, reducing exposure of water and sanitation systems to
    flooding and extreme weather events, and improved early warning systems. For vector-borne
    diseases, effective adaptation options include surveillance, early warning systems,
    and vaccine development. Effective adaptation options for reducing mental health
    risks under climate change include improving surveillance and access to mental
    health care, and monitoring of psychosocial impacts from extreme weather events.
    A key pathway to climate resilience in the health sector is universal access to
    healthcare.
  - 'Co-Benefits of Adaptation and Mitigation for Sustainable Development Goals  Mitigation
    and adaptation actions have more synergies than trade-offs with Sustainable Development
    Goals . Synergies and trade-offs depend on context and scale of implementation.
    Potential trade-offs can be compensated or avoided with additional policies, investments
    and financial partnerships. Many mitigation and adaptation actions have multiple
    synergies with Sustainable Development Goals, but some actions can also have trade-offs.
    Potential synergies with SDGs exceed potential trade-offs. Synergies and trade-offs
    are context specific and depend on: means and scale of implementation, intra-
    and inter-sectoral interactions, cooperation between countries and regions, the
    sequencing, timing and stringency of actions, governance, and policy design. Eradicating
    extreme poverty, energy poverty, and providing decent living standards to all,
    consistent with nearterm sustainable development objectives, can be achieved without
    significant global emissions growth.  Several mitigation and adaptation options
    can harness nearterm synergies and reduce trade-offs to advance sustainable development
    in energy, urban and land systems . Clean energy supply systems have multiple
    co-benefits, including improvements in air quality and health. Heat Health Action
    Plans that include early warning and response systems, approaches that mainstream
    health into food, livelihoods, social protection, water and sanitation benefit
    health and wellbeing. There are potential synergies between multiple Sustainable
    Development Goals and sustainable land use and urban planning with more green
    spaces, reduced air pollution, and demand-side mitigation including shifts to
    balanced, sustainable healthy diets. Electrification combined with low-GHG energy,
    and shifts to public transport can enhance health, employment, and can contribute
    to energy security and deliver equity. Conservation, protection and restoration
    of terrestrial, freshwater, coastal and ocean ecosystems, together with targeted
    management to adapt to unavoidable impacts of climate change can generate multiple
    additional benefits, such as agricultural productivity, food security, and biodiversity
    conservation.  When implementing mitigation and adaptation together, and taking
    trade-offs into account, multiple co-benefits and synergies for human well-being
    as well as ecosystem and planetary health can be realised. There is a strong link
    between sustainable development, vulnerability and climate risks. Social safety
    nets that support climate change adaptation have strong co-benefits with development
    goals such as education, poverty alleviation, gender inclusion and food security.
    Land restoration contributes to mitigation and adaptation with synergies via enhanced
    ecosystem services and with economically positive returns and co-benefits for
    poverty reduction and improved livelihoods. Trade-offs can be evaluated and minimised
    by giving emphasis to capacity building, finance, technology transfer, investments;
    governance, development, context specific gender-based and other social equity
    considerations with meaningful participation of Indigenous Peoples, local communities
    and vulnerable populations. .  Context relevant design and implementation requires
    considering people’s needs, biodiversity, and other sustainable development dimensions.
    Countries at all stages of economic development seek to improve the well-being
    of people, and their development priorities reflect different starting points
    and contexts. Different contexts include but are not limited to social, economic,
    environmental, cultural, or political circumstances, resource endowment, capabilities,
    international environment, and prior development. n regions with high dependency
    on fossil fuels for, among other things, revenue and employment generation, mitigating
    risks for sustainable development requires policies that promote economic and
    energy sector diversification and considerations of just transitions principles,
    processes and practices. For individuals and households in low-lying coastal areas,
    in Small Islands, and smallholder farmers transitioning from incremental to transformational
    adaptation can help overcome soft adaptation limits. Effective governance is needed
    to limit trade-offs of some mitigation options such as large scale afforestation
    and bioenergy options due to risks from their deployment for food systems, biodiversity,
    other ecosystem functions and services, and livelihoods. Effective governance
    requires adequate institutional capacity at all levels .'
  C.2.4:
  - Synergies and trade-offs, costs and benefits  Mitigation and adaptation options
    can lead to synergies and trade-offs with other aspects of sustainable development
    . Synergies and trade-offs depend on the pace and magnitude of changes and the
    development context including inequalities, with consideration of climate justice.
    The potential or effectiveness of some adaptation and mitigation options decreases
    as climate change intensifies .  In the energy sector, transitions to low-emission
    systems will have multiple co-benefits, including improvements in air quality
    and health. There are potential synergies between sustainable development and,
    for instance, energy efficiency and renewable energy.  For agriculture, land,
    and food systems, many land management options and demand-side response options  can
    contribute to eradicating poverty and eliminating hunger while promoting good
    health and well-being, clean water and sanitation, and life on land . In contrast,
    certain adaptation options that promote intensification of production, such as
    irrigation, may have negative effects on sustainability  .  Reforestation, improved
    forest management, soil carbon sequestration, peatland restoration and coastal
    blue carbon management are examples of CDR methods that can enhance biodiversity
    and ecosystem functions, employment and local livelihoods, depending on context
    . However, afforestation or production of biomass crops for bioenergy with carbon
    dioxide capture and storage or biochar can have adverse socio-economic and environmental
    impacts, including on biodiversity, food and water security, local livelihoods
    and the rights of Indigenous Peoples, especially if implemented at large scales
    and where land tenure is insecure.  Modelled pathways that assume using resources
    more efficiently or shift global development towards sustainability include fewer
    challenges, such as dependence on CDR and pressure on land and biodiversity, and
    have the most pronounced synergies with respect to sustainable development .  Strengthening
    climate change mitigation action entails more rapid transitions and higher up-front
    investments, but brings benefits from avoiding damages from climate change and
    reduced adaptation costs. The aggregate effects of climate change mitigation on
    global GDP  are small compared to global projected GDP growth. Projected estimates
    of global aggregate net economic damages and the costs of adaptation generally
    increase with global warming level.  Cost-benefit analysis remains limited in
    its ability to represent all damages from climate change, including non-monetary
    damages, or to capture the heterogeneous nature of damages and the risk of catastrophic
    damages. Even without accounting for these factors or for the co-benefits of mitigation,
    the global benefits of limiting warming to 2°C exceed the cost of mitigation .
    This finding is robust against a wide range of assumptions about social preferences
    on inequalities and discounting over time . Limiting global warming to 1.5°C instead
    of 2°C would increase the costs of mitigation, but also increase the benefits
    in terms of reduced impacts and related risks and reduced adaptation needs 140.  Considering
    other sustainable development dimensions, such as the potentially strong economic
    benefits on human health from air quality improvement, may enhance the estimated
    benefits of mitigation . The economic effects of strengthened mitigation action
    vary across regions and countries, depending notably on economic structure, regional
    emissions reductions, policy design and level of international cooperation. Ambitious
    mitigation pathways imply large and sometimes disruptive changes in economic structure,
    with implications for near-term actions, equity , sustainability, and finance
    .
  - 'Benefits of Strengthening Near-Term Action  Accelerated implementation of adaptation
    will improve well-being by reducing losses and damages, especially for vulnerable
    populations. Deep, rapid, and sustained mitigation actions would reduce future
    adaptation costs and losses and damages, enhance sustainable development co-benefits,
    avoid locking-in emission sources, and reduce stranded assets and irreversible
    climate changes. These near-term actions involve higher up-front investments and
    disruptive changes, which can be moderated by a range of enabling conditions and
    removal or reduction of barriers to feasibility. Accelerated implementation of
    adaptation responses will bring benefits to human well-being. As adaptation options
    often have long implementation times, long-term planning and accelerated implementation,
    particularly in this decade, is important to close adaptation gaps, recognising
    that constraints remain for some regions. The benefits to vulnerable populations
    would be high .  Near-term actions that limit global warming to close to 1.5°C
    would substantially reduce projected losses and damages related to climate change
    in human systems and ecosystems, compared to higher warming levels, but cannot
    eliminate them all . The magnitude and rate of climate change and associated risks
    depend strongly on near-term mitigation and adaptation actions, and projected
    adverse impacts and related losses and damages escalate with every increment of
    global warming. Delayed mitigation action will further increase global warming
    which will decrease the effectiveness of many adaptation options, including Ecosystem-based
    Adaptation and many water-related options, as well as increasing mitigation feasibility
    risks, such as for options based on ecosystems. Comprehensive, effective, and
    innovative responses integrating adaptation and mitigation can harness synergies
    and reduce trade-offs between adaptation and mitigation, as well as in meeting
    requirements for financing .  Mitigation actions will have other sustainable development
    co-benefits. Mitigation will improve air quality and human health in the near
    term notably because many air pollutants are co-emitted by GHG emitting sectors
    and because methane emissions leads to surface ozone formation. The benefits from
    air quality improvement include prevention of air pollution-related premature
    deaths, chronic diseases and damages to ecosystems and crops. The economic benefits
    for human health from air quality improvement arising from mitigation action can
    be of the same order of magnitude as mitigation costs, and potentially even larger
    . As methane has a short lifetime but is a potent GHG, strong, rapid and sustained
    reductions in methane emissions can limit near-term warming and improve air quality
    by reducing global surface ozone.  Challenges from delayed adaptation and mitigation
    actions include the risk of cost escalation, lock-in of infrastructure, stranded
    assets, and reduced feasibility and effectiveness of adaptation and mitigation
    options. The continued installation of unabated fossil fuel infrastructure will
    ‘lock-in’ GHG emissions. Limiting global warming to 2°C or below will leave a
    substantial amount of fossil fuels unburned and could strand considerable fossil
    fuel infrastructure , with globally discounted value projected to be around USD
    1 to 4 trillion from 2015 to 2050. Early actions would limit the size of these
    stranded assets, whereas delayed actions with continued investments in unabated
    high-emitting infrastructure and limited development and deployment of low-emitting
    alternatives prior to 2030 would raise future stranded assets to the higher end
    of the range – thereby acting as barriers and increasing political economy feasibility
    risks that may jeopardise efforts to limit global warming. .  Scaling-up near-term
    climate actions will mobilise a mix of low-cost and high-cost options. High-cost
    options, as in energy and infrastructure, are needed to avoid future lock-ins,
    foster innovation and initiate transformational changes. Climate resilient development
    pathways in support of sustainable development for all are shaped by equity, and
    social and climate justice. Embedding effective and equitable adaptation and mitigation
    in development planning can reduce vulnerability, conserve and restore ecosystems,
    and enable climate resilient development. This is especially challenging in localities
    with persistent development gaps and limited resources.  Scaling-up climate action
    may generate disruptive changes in economic structure with distributional consequences
    and need to reconcile divergent interests, values and worldviews, within and between
    countries. Deeper fiscal, financial, institutional and regulatory reforms can
    offset such adverse effects and unlock mitigation potentials. Societal choices
    and actions implemented in this decade will determine the extent to which medium
    and long-term development pathways will deliver higher or lower climate resilient
    development outcomes.  Enabling conditions would need to be strengthened in the
    nearterm and barriers reduced or removed to realise opportunities for deep and
    rapid adaptation and mitigation actions and climate resilient development. These
    enabling conditions are differentiated by national, regional and local circumstances
    and geographies, according to capabilities, and include: equity and inclusion
    in climate action, rapid and far-reaching transitions in sectors and system ,
    measures to achieve synergies and reduce tradeoffs with sustainable development
    goals, governance and policy improvements, access to finance, improved international
    cooperation and technology improvements, and integration of near-term actions
    across sectors, systems and regions.  Barriers to feasibility would need to be
    reduced or removed to deploy mitigation and adaptation options at scale. Many
    limits to feasibility and effectiveness of responses can be overcome by addressing
    a range of barriers, including economic, technological, institutional, social,
    environmental and geophysical barriers. The feasibility and effectiveness of options
    increase with integrated, multi-sectoral solutions that differentiate responses
    based on climate risk, cut across systems and address social inequities. Strengthened
    near-term actions in modelled cost-effective pathways that limit global warming
    to 2°C or lower, reduce the overall risk to the feasibility of the system transitions,
    compared to modelled pathways with delayed or uncoordinated action.  Integrating
    ambitious climate actions with macroeconomic policies under global uncertainty
    would provide benefits . This encompasses three main directions: economy-wide
    mainstreaming packages supporting options to improved sustainable low-emission
    economic recovery, development and job creation programs  safety nets and social
    protection in the transition; and broadened access to finance, technology and
    capacity-building and coordinated support to low-emission infrastructure , especially
    in developing regions, and under debt stress .'
  C.2.5:
  - 'Benefits of Strengthening Near-Term Action  Accelerated implementation of adaptation
    will improve well-being by reducing losses and damages, especially for vulnerable
    populations. Deep, rapid, and sustained mitigation actions would reduce future
    adaptation costs and losses and damages, enhance sustainable development co-benefits,
    avoid locking-in emission sources, and reduce stranded assets and irreversible
    climate changes. These near-term actions involve higher up-front investments and
    disruptive changes, which can be moderated by a range of enabling conditions and
    removal or reduction of barriers to feasibility. Accelerated implementation of
    adaptation responses will bring benefits to human well-being. As adaptation options
    often have long implementation times, long-term planning and accelerated implementation,
    particularly in this decade, is important to close adaptation gaps, recognising
    that constraints remain for some regions. The benefits to vulnerable populations
    would be high .  Near-term actions that limit global warming to close to 1.5°C
    would substantially reduce projected losses and damages related to climate change
    in human systems and ecosystems, compared to higher warming levels, but cannot
    eliminate them all . The magnitude and rate of climate change and associated risks
    depend strongly on near-term mitigation and adaptation actions, and projected
    adverse impacts and related losses and damages escalate with every increment of
    global warming. Delayed mitigation action will further increase global warming
    which will decrease the effectiveness of many adaptation options, including Ecosystem-based
    Adaptation and many water-related options, as well as increasing mitigation feasibility
    risks, such as for options based on ecosystems. Comprehensive, effective, and
    innovative responses integrating adaptation and mitigation can harness synergies
    and reduce trade-offs between adaptation and mitigation, as well as in meeting
    requirements for financing .  Mitigation actions will have other sustainable development
    co-benefits. Mitigation will improve air quality and human health in the near
    term notably because many air pollutants are co-emitted by GHG emitting sectors
    and because methane emissions leads to surface ozone formation. The benefits from
    air quality improvement include prevention of air pollution-related premature
    deaths, chronic diseases and damages to ecosystems and crops. The economic benefits
    for human health from air quality improvement arising from mitigation action can
    be of the same order of magnitude as mitigation costs, and potentially even larger
    . As methane has a short lifetime but is a potent GHG, strong, rapid and sustained
    reductions in methane emissions can limit near-term warming and improve air quality
    by reducing global surface ozone.  Challenges from delayed adaptation and mitigation
    actions include the risk of cost escalation, lock-in of infrastructure, stranded
    assets, and reduced feasibility and effectiveness of adaptation and mitigation
    options. The continued installation of unabated fossil fuel infrastructure will
    ‘lock-in’ GHG emissions. Limiting global warming to 2°C or below will leave a
    substantial amount of fossil fuels unburned and could strand considerable fossil
    fuel infrastructure , with globally discounted value projected to be around USD
    1 to 4 trillion from 2015 to 2050. Early actions would limit the size of these
    stranded assets, whereas delayed actions with continued investments in unabated
    high-emitting infrastructure and limited development and deployment of low-emitting
    alternatives prior to 2030 would raise future stranded assets to the higher end
    of the range – thereby acting as barriers and increasing political economy feasibility
    risks that may jeopardise efforts to limit global warming. .  Scaling-up near-term
    climate actions will mobilise a mix of low-cost and high-cost options. High-cost
    options, as in energy and infrastructure, are needed to avoid future lock-ins,
    foster innovation and initiate transformational changes. Climate resilient development
    pathways in support of sustainable development for all are shaped by equity, and
    social and climate justice. Embedding effective and equitable adaptation and mitigation
    in development planning can reduce vulnerability, conserve and restore ecosystems,
    and enable climate resilient development. This is especially challenging in localities
    with persistent development gaps and limited resources.  Scaling-up climate action
    may generate disruptive changes in economic structure with distributional consequences
    and need to reconcile divergent interests, values and worldviews, within and between
    countries. Deeper fiscal, financial, institutional and regulatory reforms can
    offset such adverse effects and unlock mitigation potentials. Societal choices
    and actions implemented in this decade will determine the extent to which medium
    and long-term development pathways will deliver higher or lower climate resilient
    development outcomes.  Enabling conditions would need to be strengthened in the
    nearterm and barriers reduced or removed to realise opportunities for deep and
    rapid adaptation and mitigation actions and climate resilient development. These
    enabling conditions are differentiated by national, regional and local circumstances
    and geographies, according to capabilities, and include: equity and inclusion
    in climate action, rapid and far-reaching transitions in sectors and system ,
    measures to achieve synergies and reduce tradeoffs with sustainable development
    goals, governance and policy improvements, access to finance, improved international
    cooperation and technology improvements, and integration of near-term actions
    across sectors, systems and regions.  Barriers to feasibility would need to be
    reduced or removed to deploy mitigation and adaptation options at scale. Many
    limits to feasibility and effectiveness of responses can be overcome by addressing
    a range of barriers, including economic, technological, institutional, social,
    environmental and geophysical barriers. The feasibility and effectiveness of options
    increase with integrated, multi-sectoral solutions that differentiate responses
    based on climate risk, cut across systems and address social inequities. Strengthened
    near-term actions in modelled cost-effective pathways that limit global warming
    to 2°C or lower, reduce the overall risk to the feasibility of the system transitions,
    compared to modelled pathways with delayed or uncoordinated action.  Integrating
    ambitious climate actions with macroeconomic policies under global uncertainty
    would provide benefits . This encompasses three main directions: economy-wide
    mainstreaming packages supporting options to improved sustainable low-emission
    economic recovery, development and job creation programs  safety nets and social
    protection in the transition; and broadened access to finance, technology and
    capacity-building and coordinated support to low-emission infrastructure , especially
    in developing regions, and under debt stress .'
  - Equity and Inclusion in Climate Change Action  Actions that prioritise equity,
    climate justice, social justice and inclusion lead to more sustainable outcomes,
    co-benefits, reduce trade-offs, support transformative change and advance climate
    resilient development. Adaptation responses are immediately needed to reduce rising
    climate risks, especially for the most vulnerable. Equity, inclusion and just
    transitions are key to progress on adaptation and deeper societal ambitions for
    accelerated mitigation. Adaptation and mitigation actions, across scales, sectors
    and regions, that prioritise equity, climate justice, rights-based approaches,
    social justice and inclusivity, lead to more sustainable outcomes, reduce trade-offs,
    support transformative change and advance climate resilient development . Redistributive
    policies across sectors and regions that shield the poor and vulnerable, social
    safety nets, equity, inclusion and just transitions, at all scales can enable
    deeper societal ambitions and resolve trade-offs with sustainable development
    goals., particularly education, hunger, poverty, gender and energy access . Mitigation
    efforts embedded within the wider development context can increase the pace, depth
    and breadth of emission reductions . Equity, inclusion and just transitions at
    all scales enable deeper societal ambitions for accelerated mitigation, and climate
    action more broadly. The complexity in risk of rising food prices, reduced household
    incomes, and health and climate-related malnutrition  and mortality increases
    with little or low levels of adaptation.  Regions and people with considerable
    development constraints have high vulnerability to climatic hazards. Adaptation
    outcomes for the most vulnerable within and across countries and regions are enhanced
    through approaches focusing on equity, inclusivity, and rights-based approaches,
    including 3.3 to 3.6 billion people living in contexts that are highly vulnerable
    to climate change. Vulnerability is higher in locations with poverty, governance
    challenges and limited access to basic services and resources, violent conflict
    and high levels of climate-sensitive livelihoods  . Several risks can be moderated
    with adaptation. The largest adaptation gaps exist among lower income population
    groups and adaptation progress is unevenly distributed with observed adaptation
    gaps. Present development challenges causing high vulnerability are influenced
    by historical and ongoing patterns of inequity such as colonialism, especially
    for many Indigenous Peoples and local communities. Vulnerability is exacerbated
    by inequity and marginalisation linked to gender, ethnicity, low income or combinations
    thereof, especially for many Indigenous Peoples and local communities.  Meaningful
    participation and inclusive planning, informed by cultural values, Indigenous
    Knowledge, local knowledge, and scientific knowledge can help address adaptation
    gaps and avoid maladaptation. Such actions with flexible pathways may encourage
    low-regret and timely actions . Integrating climate adaptation into social protection
    programmes, including cash transfers and public works programmes, would increase
    resilience to climate change, especially when supported by basic services and
    infrastructure.  Equity, inclusion, just transitions, broad and meaningful participation
    of all relevant actors in decision making at all scales enable deeper societal
    ambitions for accelerated mitigation, and climate action more broadly, and build
    social trust, support transformative changes and an equitable sharing of benefits
    and burdens. Equity remains a central element in the UN climate regime, notwithstanding
    shifts in differentiation between states over time and challenges in assessing
    fair shares. Ambitious mitigation pathways imply large and sometimes disruptive
    changes in economic structure, with significant distributional consequences, within
    and between countries, including shifting of income and employment during the
    transition from high to low emissions activities. While some jobs may be lost,
    low-emissions development can also open up opportunities to enhance skills and
    create jobs. Broadening equitable access to finance, technologies and governance
    that facilitate mitigation, and consideration of climate justice can help equitable
    sharing of benefits and burdens, especially for vulnerable countries and communities.  Development
    priorities among countries also reflect different starting points and contexts,
    and enabling conditions for shifting development pathways towards increased sustainability
    will therefore differ, giving rise to different needs . Implementing just transition
    principles through collective and participatory decision-making processes is an
    effective way of integrating equity principles into policies at all scales depending
    on national circumstances, while in several countries just transition commissions,
    task forces and national policies have been established .  Many economic and regulatory
    instruments have been effective in reducing emissions and practical experience
    has informed instrument design to improve them while addressing distributional
    goals and social acceptance. The design of behavioural interventions, including
    the way that choices are presented to consumers work synergistically with price
    signals, making the combination more effective. Individuals with high socio-economic
    status contribute disproportionately to emissions, and have the highest potential
    for emissions reductions, e.g., as citizens, investors, consumers, role models,
    and professionals . There are options on design of instruments such as taxes,
    subsidies, prices, and consumption-based approaches, complemented by regulatory
    instruments to reduce high-emissions consumption while improving equity and societal
    well-being. Behaviour and lifestyle changes to help end-users adopt low-GHG-intensive
    options can be supported by policies, infrastructure and technology with multiple
    co-benefits for societal well-being. Broadening equitable access to domestic and
    international finance, technologies and capacity can also act as a catalyst for
    accelerating mitigation and shifting development pathways in low-income contexts
    . Eradicating extreme poverty, energy poverty, and providing decent living standards
    to all in these regions in the context of achieving sustainable development objectives,
    in the near term, can be achieved without significant global emissions growth.
    Technology development, transfer, capacity building and financing can support
    developing countries/ regions leapfrogging or transitioning to low-emissions transport
    systems thereby providing multiple co-benefits . Climate resilient development
    is advanced when actors work in equitable, just and enabling ways to reconcile
    divergent interests, values and worldviews, toward equitable and just outcomes
    .
  - Governance and Policy for Near-Term Climate Change Action  Effective climate action
    requires political commitment, well-aligned multi-level governance and institutional
    frameworks, laws, policies and strategies. It needs clear goals, adequate finance
    and financing tools, coordination across multiple policy domains, and inclusive
    governance processes. Many mitigation and adaptation policy instruments have been
    deployed successfully, and could support deep emissions reductions and climate
    resilience if scaled up and applied widely, depending on national circumstances.
    Adaptation and mitigation action benefits from drawing on diverse knowledge. Effective
    climate governance enables mitigation and adaptation by providing overall direction
    based on national circumstances, setting targets and priorities, mainstreaming
    climate action across policy domains and levels, based on national circumstances
    and in the context of international cooperation. Effective governance enhances
    monitoring and evaluation and regulatory certainty, prioritising inclusive, transparent
    and equitable decision-making, and improves access to finance and technology.
    These functions can be promoted by climate-relevant laws and plans, which are
    growing in number across sectors and regions, advancing mitigation outcomes and
    adaptation benefits . Climate laws have been growing in number and have helped
    deliver mitigation and adaptation outcomes .  Effective municipal, national and
    sub-national climate institutions, such as expert and co-ordinating bodies, enable
    co-produced, multi-scale decision-processes, build consensus for action among
    diverse interests, and inform strategy settings . This requires adequate institutional
    capacity at all levels. Vulnerabilities and climate risks are often reduced through
    carefully designed and implemented laws, policies, participatory processes, and
    interventions that address context specific inequities such as based on gender,
    ethnicity, disability, age, location and income. Policy support is influenced
    by Indigenous Peoples, businesses, and actors in civil society, including, youth,
    labour, media, and local communities, and effectiveness is enhanced by partnerships
    between many different groups in society . Climate-related litigation is growing,
    with a large number of cases in some developed countries and with a much smaller
    number in some developing countries, and in some cases has influenced the outcome
    and ambition of climate governance.  Effective climate governance is enabled by
    inclusive decision processes, allocation of appropriate resources, and institutional
    review, monitoring and evaluation. Multi-level, hybrid and cross-sector governance
    facilitates appropriate consideration for co-benefits and trade-offs, particularly
    in land sectors where decision processes range from farm level to national scale.
    Consideration of climate justice can help to facilitate shifting development pathways
    towards sustainability.  Drawing on diverse knowledge and partnerships, including
    with women, youth, Indigenous Peoples, local communities, and ethnic minorities
    can facilitate climate resilient development and has allowed locally appropriate
    and socially acceptable solutions.  Many regulatory and economic instruments have
    already been deployed successfully. These instruments could support deep emissions
    reductions if scaled up and applied more widely. Practical experience has informed
    instrument design and helped to improve predictability, environmental effectiveness,
    economic efficiency, and equity.  Scaling up and enhancing the use of regulatory
    instruments, consistent with national circumstances, can improve mitigation outcomes
    in sectoral applications, and regulatory instruments that include flexibility
    mechanisms can reduce costs of cutting emissions.  Where implemented, carbon pricing
    instruments have incentivized low-cost emissions reduction measures, but have
    been less effective, on their own and at prevailing prices during the assessment
    period, to promote higher-cost measures necessary for further reductions. Revenue
    from carbon taxes or emissions trading can be used for equity and distributional
    goals, for example to support low-income households, among other approaches. There
    is no consistent evidence that current emission trading systems have led to significant
    emissions leakage.  Removing fossil fuel subsidies would reduce emissions, improve
    public revenue and macroeconomic performance, and yield other environmental and
    sustainable development benefits such as improved public revenue, macroeconomic
    and sustainability performance; subsidy removal can have adverse distributional
    impacts especially on the most economically vulnerable groups which, in some cases,
    can be mitigated by measures such as re-distributing revenue saved, and depend
    on national circumstances. Fossil fuel subsidy removal is projected by various
    studies to reduce global CO 2 emissions by 1–4%, and GHG emissions by up to 10%
    by 2030, varying across regions .  National policies to support technology development,
    and participation in international markets for emission reduction, can bring positive
    spillover effects for other countries , although reduced demand for fossil fuels
    as a result of climate policy could result in costs to exporting countries . Economy-wide
    packages can meet short-term economic goals while reducing emissions and shifting
    development pathways towards sustainability. Examples are public spending commitments;
    pricing reforms; and investment in education and training, R&D and infrastructure.
    Effective policy packages would be comprehensive in coverage, harnessed to a clear
    vision for change, balanced across objectives, aligned with specific technology
    and system needs, consistent in terms of design and tailored to national circumstances
    .
  - Finance for Mitigation and Adaptation Actions  Improved availability and access
    to finance will enable accelerated climate action. Addressing needs and gaps and
    broadening equitable access to domestic and international finance, when combined
    with other supportive actions, can act as a catalyst for accelerating mitigation
    and shifting development pathways. Climate resilient development is enabled by
    increased international cooperation including improved access to financial resources,
    particularly for vulnerable regions, sectors and groups, and inclusive governance
    and coordinated policies . Accelerated international financial cooperation is
    a critical enabler of low-GHG and just transitions, and can address inequities
    in access to finance and the costs of, and vulnerability to, the impacts of climate
    change.  Both adaptation and mitigation finance need to increase many-fold, to
    address rising climate risks and to accelerate investments in emissions reduction.
    Increased finance would address soft limits to adaptation and rising climate risks
    while also averting some related losses and damages, particularly in vulnerable
    developing countries. Enhanced mobilisation of and access to finance, together
    with building capacity, are essential for implementation of adaptation actions
    and to reduce adaptation gaps given rising risks and costs, especially for the
    most vulnerable groups, regions and sectors . Public finance is an important enabler
    of adaptation and mitigation, and can also leverage private finance. Adaptation
    funding predominately comes from public sources, and public mechanisms and finance
    can leverage private sector finance by addressing real and perceived regulatory,
    cost and market barriers, for instance via public-private partnerships. Financial
    and technological resources enable effective and ongoing implementation of adaptation,
    especially when supported by institutions with a strong understanding of adaptation
    needs and capacity. Average annual modelled mitigation investment requirements
    for 2020 to 2030 in scenarios that limit warming to 2°C or 1.5°C are a factor
    of three to six greater than current levels, and total mitigation investments
    would need to increase across all sectors and regions. Even if extensive global
    mitigation efforts are implemented, there will be a large need for financial,
    technical, and human resources for adaptation .
  C.3.1:
  - 'The Timing and Urgency of Climate Action  The magnitude and rate of climate change
    and associated risks depend strongly on near-term mitigation and adaptation actions
    . Global warming is more likely than not to reach 1.5°C between 2021 and 2040
    even under the very low GHG emission scenarios, and likely or very likely to exceed
    1.5°C under higher emissions scenarios 141. Many adaptation options have medium
    or high feasibility up to 1.5°C , but hard limits to adaptation have already been
    reached in some ecosystems and the effectiveness of adaptation to reduce climate
    risk will decrease with increasing warming. Societal choices and actions implemented
    in this decade determine the extent to which medium- and long-term pathways will
    deliver higher or lower climate resilient development. Climate resilient development
    prospects are increasingly limited if current greenhouse gas emissions do not
    rapidly decline, especially if 1.5°C global warming is exceeded in the near term.
    Without urgent, effective and equitable adaptation and mitigation actions, climate
    change increasingly threatens the health and livelihoods of people around the
    globe, ecosystem health, and biodiversity, with severe adverse consequences for
    current and future generations. .  In modelled pathways that limit warming to
    1.5°C with no or limited overshoot and in those that limit warming to 2°C, assuming
    immediate actions, global GHG emissions are projected to peak in the early 2020s
    followed by rapid and deep GHG emissions reductions 142 . In pathways that limit
    warming to 1.5°C with no or limited overshoot, net global GHG emissions are projected
    to fall by 43 [34 to 60]%143 below 2019 levels by 2030, 60 [49 to 77]% by 2035,
    69 [58 to 90]% by 2040 and 84 [73 to 98]% by 2050 144. Global modelled pathways
    that limit warming to 2°C have reductions in GHG emissions below 2019 levels of
    21 [1 to 42]% by 2030, 35 [22 to 55] % by 2035, 46 [34 to 63] % by 2040 and 64
    [53 to 77]% by 2050145. Global GHG emissions associated with NDCs announced prior
    to COP26 would make it likely that warming would exceed 1.5°C and limiting warming
    to 2°C would then imply a rapid acceleration of emission reductions during 2030–2050,
    around 70% faster than in pathways where immediate action is taken to limit warming
    to 2°C Continued investments in unabated high-emitting infrastructure and limited
    development and deployment of low-emitting alternatives prior to 2030 would act
    as barriers to this acceleration and increase feasibility risks.  All global modelled
    pathways that limit warming to 2°C or lower by 2100 involve reductions in both
    net CO 2 emissions and non-CO 2 emissions. For example, in pathways that limit
    warming to 1.5°C with no or limited overshoot, global CH4 emissions are reduced
    by 34 [21 to 57]% below 2019 levels by 2030 and by 44 [31 to 63]% in 2040. Global
    CH 4 emissions are reduced by 24 [9 to 53]% below 2019 levels by 2030 and by 37
    [20 to 60]% in 2040 in modelled pathways that limit warming to 2°C with action
    starting in 2020.  All global modelled pathways that limit warming to 2°C or lower
    by 2100 involve GHG emission reductions in all sectors . The contributions of
    different sectors vary across modelled mitigation pathways. In most global modelled
    mitigation pathways, emissions from land-use, land-use change and forestry, via
    reforestation and reduced deforestation, and from the energy supply sector reach
    net zero CO2 emissions earlier than the buildings, industry and transport sectors.
    Strategies can rely on combinations of different options, but doing less in one
    sector needs to be compensated by further reductions in other sectors if warming
    is to be limited.  Without rapid, deep and sustained mitigation and accelerated
    adaptation actions, losses and damages will continue to increase, including projected
    adverse impacts in Africa, LDCs, SIDS, Central and South America , Asia and the
    Arctic, and will disproportionately affect the most vulnerable populations .  '
  - 'Energy Systems  Rapid and deep reductions in GHG emissions require major energy
    system transitions. Adaptation options can help reduce climate-related risks to
    the energy system . Net zero CO2 energy systems entail: a substantial reduction
    in overall fossil fuel use, minimal use of unabated fossil fuels 153, and use
    of Carbon Capture and Storage in the remaining fossil fuel systems; electricity
    systems that emit no net CO 2; widespread electrification; alternative energy
    carriers in applications less amenable to electrification; energy conservation
    and efficiency; and greater integration across the energy system . Large contributions
    to emissions reductions can come from options costing less than USD 20 tCO 2 -eq
    –1, including solar and wind energy, energy efficiency improvements, and CH4 emissions
    reductions  . 154 Many of these response options are technically viable and are
    supported by the public. Maintaining emission-intensive systems may, in some regions
    and sectors, be more expensive than transitioning to low emission systems.  Climate
    change and related extreme events will affect future energy systems, including
    hydropower production, bioenergy yields, thermal power plant efficiencies, and
    demands for heating and cooling . The most feasible energy system adaptation options
    support infrastructure resilience, reliable power systems and efficient water
    use for existing and new energy generation systems . Adaptations for hydropower
    and thermo-electric power generation are effective in most regions up to 1.5°C
    to 2°C, with decreasing effectiveness at higher levels of warming . Energy generation
    diversification  and demand side management  can increase energy reliability and
    reduce vulnerabilities to climate change, especially in rural populations . Climate
    responsive energy markets, updated design standards on energy assets according
    to current and projected climate change, smart-grid technologies, robust transmission
    systems and improved capacity to respond to supply deficits have high feasibility
    in the medium- to long-term, with mitigation co-benefits .'
  - Society, Livelihoods, and Economies  Enhancing knowledge on risks and available
    adaptation options promotes societal responses, and behaviour and lifestyle changes
    supported by policies, infrastructure and technology can help reduce global GHG
    emissions. Climate literacy and information provided through climate services
    and community approaches, including those that are informed by Indigenous Knowledge
    and local knowledge, can accelerate behavioural changes and planning . Educational
    and information programmes, using the arts, participatory modelling and citizen
    science can facilitate awareness, heighten risk perception, and influence behaviours
    . The way choices are presented can enable adoption of low GHG intensive socio-cultural
    options, such as shifts to balanced, sustainable healthy diets, reduced food waste,
    and active mobility. Judicious labelling, framing, and communication of social
    norms can increase the effect of mandates, subsidies, or taxes.  A range of adaptation
    options, such as disaster risk management, early warning systems, climate services
    and risk spreading and sharing approaches, have broad applicability across sectors
    and provide greater risk reduction benefits when combined . Climate services that
    are demand-driven and inclusive of different users and providers can improve agricultural
    practices, inform better water use and efficiency, and enable resilient infrastructure
    planning. Policy mixes that include weather and health insurance, social protection
    and adaptive safety nets, contingent finance and reserve funds, and universal
    access to early warning systems combined with effective contingency plans, can
    reduce vulnerability and exposure of human systems. Integrating climate adaptation
    into social protection programs, including cash transfers and public works programs,
    is highly feasible and increases resilience to climate change, especially when
    supported by basic services and infrastructure. Social safety nets can build adaptive
    capacities, reduce socioeconomic vulnerability, and reduce risk linked to hazards.  Reducing
    future risks of involuntary migration and displacement due to climate change is
    possible through cooperative, international efforts to enhance institutional adaptive
    capacity and sustainable development. Increasing adaptive capacity minimises risk
    associated with involuntary migration and immobility and improves the degree of
    choice under which migration decisions are made, while policy interventions can
    remove barriers and expand the alternatives for safe, orderly and regular migration
    that allows vulnerable people to adapt to climate change.  Accelerating commitment
    and follow-through by the private sector is promoted for instance by building
    business cases for adaptation, accountability and transparency mechanisms, and
    monitoring and evaluation of adaptation progress . Integrated pathways for managing
    climate risks will be most suitable when so-called ‘low-regret’ anticipatory options
    are established jointly across sectors in a timely manner and are feasible and
    effective in their local context, and when path dependencies and maladaptations
    across sectors are avoided. Sustained adaptation actions are strengthened by mainstreaming
    adaptation into institutional budget and policy planning cycles, statutory planning,
    monitoring and evaluation frameworks and into recovery efforts from disaster events.
    Instruments that incorporate adaptation such as policy and legal frameworks, behavioural
    incentives, and economic instruments that address market failures, such as climate
    risk disclosure, inclusive and deliberative processes strengthen adaptation actions
    by public and private actors.
  - Industry  There are several options to reduce industrial emissions that differ
    by type of industry; many industries are disrupted by climate change, especially
    from extreme events . Reducing industry emissions will entail coordinated action
    throughout value chains to promote all mitigation options, including demand management,
    energy and materials efficiency, circular material flows, as well as abatement
    technologies and transformational changes in production processes. Light industry
    and manufacturing can be largely decarbonized through available abatement technologies,
    electrification, and switching to low- and zero-GHG emitting fuels  , while deep
    reduction of cement process emissions will rely on cementitious material substitution
    and the availability of Carbon Capture and Storage until new chemistries are mastered.
    Reducing emissions from the production and use of chemicals would need to rely
    on a life cycle approach, including increased plastics recycling, fuel and feedstock
    switching, and carbon sourced through biogenic sources, and, depending on availability,
    Carbon Capture and Utilisation, direct air CO2 capture, as well as CCS. Action
    to reduce industry sector emissions may change the location of GHG-intensive industries
    and the organisation of value chains, with distributional effects on employment
    and economic structure.  Many industrial and service sectors are negatively affected
    by climate change through supply and operational disruptions, especially from
    extreme events, and will require adaptation efforts. Water intensive industries
    can undertake measures to reduce water stress, such as water recycling and reuse,
    using brackish or saline sources, working to improve water use efficiency. However,
    residual risks will remain, especially at higher levels of warming .
  - 'Cities, Settlements and Infrastructure  Urban systems are critical for achieving
    deep emissions reductions and advancing climate resilient development, particularly
    when this involves integrated planning that incorporates physical, natural and
    social infrastructure . Deep emissions reductions and integrated adaptation actions
    are advanced by: integrated, inclusive land use planning and decision-making;
    compact urban form by co-locating jobs and housing; reducing or changing urban
    energy and material consumption; electrification in combination with low emissions
    sources; improved water and waste management infrastructure; and enhancing carbon
    uptake and storage in the urban environment . Cities can achieve net zero emissions
    if emissions are reduced within and outside of their administrative boundaries
    through supply chains, creating beneficial cascading effects across other sectors.  Considering
    climate change impacts and risks  in the design and planning of urban and rural
    settlements and infrastructure is critical for resilience and enhancing human
    well-being. Effective mitigation can be advanced at each of the design, construction,
    retrofit, use and disposal stages for buildings. Mitigation interventions for
    buildings include: at the construction phase, lowemission construction materials,
    highly efficient building envelope and the integration of renewable energy solutions;
    at the use phase, highly efficient appliances/equipment, the optimisation of the
    use of buildings and their supply with low-emission energy sources; and at the
    disposal phase, recycling and re-using construction materials. Sufficiency 155
    measures can limit the demand for energy and materials over the lifecycle of buildings
    and appliances.   Transport-related GHG emissions can be reduced by demand-side
    options and low-GHG emissions technologies. Changes in urban form, reallocation
    of street space for cycling and walking, digitalisation and programs that encourage
    changes in consumer behaviour can reduce demand for transport services and support
    the shift to more energy efficient transport modes. Electric vehicles powered
    by low-emissions electricity offer the largest decarbonisation potential for land-based
    transport, on a life cycle basis. Costs of electrified vehicles are decreasing
    and their adoption is accelerating, but they require continued investments in
    supporting infrastructure to increase scale of deployment. The environmental footprint
    of battery production and growing concerns about critical minerals can be addressed
    by material and supply diversification strategies, energy and material efficiency
    improvements, and circular material flows . Advances in battery technologies could
    facilitate the electrification of heavy-duty trucks and compliment conventional
    electric rail systems. Sustainable biofuels can offer additional mitigation benefits
    in land-based transport in the short and medium term. Sustainable biofuels, low-emissions
    hydrogen, and derivatives can support mitigation of CO2 emissions from shipping,
    aviation, and heavy-duty land transport but require production process improvements
    and cost reductions. Key infrastructure systems including sanitation, water, health,
    transport, communications and energy will be increasingly vulnerable if design
    standards do not account for changing climate conditions.  Green/natural and blue
    infrastructure such as urban forestry, green roofs, ponds and lakes, and river
    restoration can mitigate climate change through carbon uptake and storage, avoided
    emissions, and reduced energy use while reducing risk from extreme events such
    as heatwaves, heavy precipitation and droughts, and advancing co-benefits for
    health, well-being and livelihoods. Urban greening can provide local cooling.
    Combining green/natural and grey/physical infrastructure adaptation responses
    has potential to reduce adaptation costs and contribute to flood control, sanitation,
    water resources management, landslide prevention and coastal protection. Globally,
    more financing is directed at grey/physical infrastructure than green/natural
    infrastructure and social infrastructure, and there is limited evidence of investment
    in informal settlements . The greatest gains in well-being in urban areas can
    be achieved by prioritising finance to reduce climate risk for low-income and
    marginalised communities including people living in informal settlements.  Responses
    to ongoing sea level rise and land subsidence in low-lying coastal cities and
    settlements and small islands include protection, accommodation, advance and planned
    relocation. These responses are more effective if combined and/or sequenced, planned
    well ahead, aligned with sociocultural values and development priorities, and
    underpinned by inclusive community engagement processes. '
  - Land, Ocean, Food, and Water  There is substantial mitigation and adaptation potential
    from options in agriculture, forestry and other land use, and in the oceans, that
    could be upscaled in the near term across most regions. Conservation, improved
    management, and restoration of forests and other ecosystems offer the largest
    share of economic mitigation potential, with reduced deforestation in tropical
    regions having the highest total mitigation potential. Ecosystem restoration,
    reforestation, and afforestation can lead to trade-offs due to competing demands
    on land. Minimizing trade-offs requires integrated approaches to meet multiple
    objectives including food security. Demand-side measures  and sustainable agricultural
    intensification can reduce ecosystem conversion and CH4 and N2 O emissions, and
    free up land for reforestation and ecosystem restoration. Sustainably sourced
    agriculture and forest products, including long-lived wood products, can be used
    instead of more GHG-intensive products in other sectors. Effective adaptation
    options include cultivar improvements, agroforestry, community-based adaptation,
    farm and landscape diversification, and urban agriculture. These AFOLU response
    options require integration of biophysical, socioeconomic and other enabling factors.
    The effectiveness of ecosystem-based adaptation and most water-related adaptation
    options declines with increasing warming.  Some options, such as conservation
    of high-carbon ecosystems , have immediate impacts while others, such as restoration
    of high-carbon ecosystems, reclamation of degraded soils or afforestation, take
    decades to deliver measurable results. Many sustainable land management technologies
    and practices are financially profitable in three to ten years.  Maintaining the
    resilience of biodiversity and ecosystem services at a global scale depends on
    effective and equitable conservation of approximately 30–50% of Earth’s land,
    freshwater and ocean areas, including currently near-natural ecosystems. The services
    and options provided by terrestrial, freshwater, coastal and ocean ecosystems
    can be supported by protection, restoration, precautionary ecosystem-based management
    of renewable resource use, and the reduction of pollution and other stressors.  Large-scale
    land conversion for bioenergy, biochar, or afforestation can increase risks to
    biodiversity, water and food security. In contrast, restoring natural forests
    and drained peatlands, and improving sustainability of managed forests enhances
    the resilience of carbon stocks and sinks and reduces ecosystem vulnerability
    to climate change. Cooperation, and inclusive decision making, with local communities
    and Indigenous Peoples, as well as recognition of inherent rights of Indigenous
    Peoples, is integral to successful adaptation across forests and other ecosystems.  Natural
    rivers, wetlands and upstream forests reduce flood risk in most circumstances.
    Enhancing natural water retention such as by restoring wetlands and rivers, land
    use planning such as no build zones or upstream forest management, can further
    reduce flood risk . For inland flooding, combinations of non-structural measures
    like early warning systems and structural measures like levees have reduced loss
    of lives, but hard defences against flooding or sea level rise can also be maladaptive
    .  Protection and restoration of coastal ‘blue carbon’ ecosystems could reduce
    emissions and/or increase carbon uptake and storage . Coastal wetlands protect
    against coastal erosion and flooding. Strengthening precautionary approaches,
    such as rebuilding overexploited or depleted fisheries, and responsiveness of
    existing fisheries management strategies reduces negative climate change impacts
    on fisheries, with benefits for regional economies and livelihoods. Ecosystem-based
    management in fisheries and aquaculture supports food security, biodiversity,
    human health and well-being.
  - Health and Nutrition  Human health will benefit from integrated mitigation and
    adaptation options that mainstream health into food, infrastructure, social protection,
    and water policies . Balanced and sustainable healthy diets and reduced food loss
    and waste present important opportunities for adaptation and mitigation while
    generating significant co-benefits in terms of biodiversity and human health.
    Public health policies to improve nutrition, such as increasing the diversity
    of food sources in public procurement, health insurance, financial incentives,
    and awareness-raising campaigns, can potentially influence food demand, reduce
    food waste, reduce healthcare costs, contribute to lower GHG emissions and enhance
    adaptive capacity. Improved access to clean energy sources and technologies, and
    shifts to active mobility and public transport can deliver socioeconomic, air
    quality and health benefits, especially for women and children.  Effective adaptation
    options exist to help protect human health and well-being. Health Action Plans
    that include early warning and response systems are effective for extreme heat
    . Effective options for water-borne and food-borne diseases include improving
    access to potable water, reducing exposure of water and sanitation systems to
    flooding and extreme weather events, and improved early warning systems. For vector-borne
    diseases, effective adaptation options include surveillance, early warning systems,
    and vaccine development. Effective adaptation options for reducing mental health
    risks under climate change include improving surveillance and access to mental
    health care, and monitoring of psychosocial impacts from extreme weather events.
    A key pathway to climate resilience in the health sector is universal access to
    healthcare.
  C.3.2:
  - 'Energy Systems  Rapid and deep reductions in GHG emissions require major energy
    system transitions. Adaptation options can help reduce climate-related risks to
    the energy system . Net zero CO2 energy systems entail: a substantial reduction
    in overall fossil fuel use, minimal use of unabated fossil fuels 153, and use
    of Carbon Capture and Storage in the remaining fossil fuel systems; electricity
    systems that emit no net CO 2; widespread electrification; alternative energy
    carriers in applications less amenable to electrification; energy conservation
    and efficiency; and greater integration across the energy system . Large contributions
    to emissions reductions can come from options costing less than USD 20 tCO 2 -eq
    –1, including solar and wind energy, energy efficiency improvements, and CH4 emissions
    reductions  . 154 Many of these response options are technically viable and are
    supported by the public. Maintaining emission-intensive systems may, in some regions
    and sectors, be more expensive than transitioning to low emission systems.  Climate
    change and related extreme events will affect future energy systems, including
    hydropower production, bioenergy yields, thermal power plant efficiencies, and
    demands for heating and cooling . The most feasible energy system adaptation options
    support infrastructure resilience, reliable power systems and efficient water
    use for existing and new energy generation systems . Adaptations for hydropower
    and thermo-electric power generation are effective in most regions up to 1.5°C
    to 2°C, with decreasing effectiveness at higher levels of warming . Energy generation
    diversification  and demand side management  can increase energy reliability and
    reduce vulnerabilities to climate change, especially in rural populations . Climate
    responsive energy markets, updated design standards on energy assets according
    to current and projected climate change, smart-grid technologies, robust transmission
    systems and improved capacity to respond to supply deficits have high feasibility
    in the medium- to long-term, with mitigation co-benefits .'
  C.3.3:
  - Industry  There are several options to reduce industrial emissions that differ
    by type of industry; many industries are disrupted by climate change, especially
    from extreme events . Reducing industry emissions will entail coordinated action
    throughout value chains to promote all mitigation options, including demand management,
    energy and materials efficiency, circular material flows, as well as abatement
    technologies and transformational changes in production processes. Light industry
    and manufacturing can be largely decarbonized through available abatement technologies,
    electrification, and switching to low- and zero-GHG emitting fuels  , while deep
    reduction of cement process emissions will rely on cementitious material substitution
    and the availability of Carbon Capture and Storage until new chemistries are mastered.
    Reducing emissions from the production and use of chemicals would need to rely
    on a life cycle approach, including increased plastics recycling, fuel and feedstock
    switching, and carbon sourced through biogenic sources, and, depending on availability,
    Carbon Capture and Utilisation, direct air CO2 capture, as well as CCS. Action
    to reduce industry sector emissions may change the location of GHG-intensive industries
    and the organisation of value chains, with distributional effects on employment
    and economic structure.  Many industrial and service sectors are negatively affected
    by climate change through supply and operational disruptions, especially from
    extreme events, and will require adaptation efforts. Water intensive industries
    can undertake measures to reduce water stress, such as water recycling and reuse,
    using brackish or saline sources, working to improve water use efficiency. However,
    residual risks will remain, especially at higher levels of warming .
  - 'Cities, Settlements and Infrastructure  Urban systems are critical for achieving
    deep emissions reductions and advancing climate resilient development, particularly
    when this involves integrated planning that incorporates physical, natural and
    social infrastructure . Deep emissions reductions and integrated adaptation actions
    are advanced by: integrated, inclusive land use planning and decision-making;
    compact urban form by co-locating jobs and housing; reducing or changing urban
    energy and material consumption; electrification in combination with low emissions
    sources; improved water and waste management infrastructure; and enhancing carbon
    uptake and storage in the urban environment . Cities can achieve net zero emissions
    if emissions are reduced within and outside of their administrative boundaries
    through supply chains, creating beneficial cascading effects across other sectors.  Considering
    climate change impacts and risks  in the design and planning of urban and rural
    settlements and infrastructure is critical for resilience and enhancing human
    well-being. Effective mitigation can be advanced at each of the design, construction,
    retrofit, use and disposal stages for buildings. Mitigation interventions for
    buildings include: at the construction phase, lowemission construction materials,
    highly efficient building envelope and the integration of renewable energy solutions;
    at the use phase, highly efficient appliances/equipment, the optimisation of the
    use of buildings and their supply with low-emission energy sources; and at the
    disposal phase, recycling and re-using construction materials. Sufficiency 155
    measures can limit the demand for energy and materials over the lifecycle of buildings
    and appliances.   Transport-related GHG emissions can be reduced by demand-side
    options and low-GHG emissions technologies. Changes in urban form, reallocation
    of street space for cycling and walking, digitalisation and programs that encourage
    changes in consumer behaviour can reduce demand for transport services and support
    the shift to more energy efficient transport modes. Electric vehicles powered
    by low-emissions electricity offer the largest decarbonisation potential for land-based
    transport, on a life cycle basis. Costs of electrified vehicles are decreasing
    and their adoption is accelerating, but they require continued investments in
    supporting infrastructure to increase scale of deployment. The environmental footprint
    of battery production and growing concerns about critical minerals can be addressed
    by material and supply diversification strategies, energy and material efficiency
    improvements, and circular material flows . Advances in battery technologies could
    facilitate the electrification of heavy-duty trucks and compliment conventional
    electric rail systems. Sustainable biofuels can offer additional mitigation benefits
    in land-based transport in the short and medium term. Sustainable biofuels, low-emissions
    hydrogen, and derivatives can support mitigation of CO2 emissions from shipping,
    aviation, and heavy-duty land transport but require production process improvements
    and cost reductions. Key infrastructure systems including sanitation, water, health,
    transport, communications and energy will be increasingly vulnerable if design
    standards do not account for changing climate conditions.  Green/natural and blue
    infrastructure such as urban forestry, green roofs, ponds and lakes, and river
    restoration can mitigate climate change through carbon uptake and storage, avoided
    emissions, and reduced energy use while reducing risk from extreme events such
    as heatwaves, heavy precipitation and droughts, and advancing co-benefits for
    health, well-being and livelihoods. Urban greening can provide local cooling.
    Combining green/natural and grey/physical infrastructure adaptation responses
    has potential to reduce adaptation costs and contribute to flood control, sanitation,
    water resources management, landslide prevention and coastal protection. Globally,
    more financing is directed at grey/physical infrastructure than green/natural
    infrastructure and social infrastructure, and there is limited evidence of investment
    in informal settlements . The greatest gains in well-being in urban areas can
    be achieved by prioritising finance to reduce climate risk for low-income and
    marginalised communities including people living in informal settlements.  Responses
    to ongoing sea level rise and land subsidence in low-lying coastal cities and
    settlements and small islands include protection, accommodation, advance and planned
    relocation. These responses are more effective if combined and/or sequenced, planned
    well ahead, aligned with sociocultural values and development priorities, and
    underpinned by inclusive community engagement processes. '
  C.3.4:
  - 'Cities, Settlements and Infrastructure  Urban systems are critical for achieving
    deep emissions reductions and advancing climate resilient development, particularly
    when this involves integrated planning that incorporates physical, natural and
    social infrastructure . Deep emissions reductions and integrated adaptation actions
    are advanced by: integrated, inclusive land use planning and decision-making;
    compact urban form by co-locating jobs and housing; reducing or changing urban
    energy and material consumption; electrification in combination with low emissions
    sources; improved water and waste management infrastructure; and enhancing carbon
    uptake and storage in the urban environment . Cities can achieve net zero emissions
    if emissions are reduced within and outside of their administrative boundaries
    through supply chains, creating beneficial cascading effects across other sectors.  Considering
    climate change impacts and risks  in the design and planning of urban and rural
    settlements and infrastructure is critical for resilience and enhancing human
    well-being. Effective mitigation can be advanced at each of the design, construction,
    retrofit, use and disposal stages for buildings. Mitigation interventions for
    buildings include: at the construction phase, lowemission construction materials,
    highly efficient building envelope and the integration of renewable energy solutions;
    at the use phase, highly efficient appliances/equipment, the optimisation of the
    use of buildings and their supply with low-emission energy sources; and at the
    disposal phase, recycling and re-using construction materials. Sufficiency 155
    measures can limit the demand for energy and materials over the lifecycle of buildings
    and appliances.   Transport-related GHG emissions can be reduced by demand-side
    options and low-GHG emissions technologies. Changes in urban form, reallocation
    of street space for cycling and walking, digitalisation and programs that encourage
    changes in consumer behaviour can reduce demand for transport services and support
    the shift to more energy efficient transport modes. Electric vehicles powered
    by low-emissions electricity offer the largest decarbonisation potential for land-based
    transport, on a life cycle basis. Costs of electrified vehicles are decreasing
    and their adoption is accelerating, but they require continued investments in
    supporting infrastructure to increase scale of deployment. The environmental footprint
    of battery production and growing concerns about critical minerals can be addressed
    by material and supply diversification strategies, energy and material efficiency
    improvements, and circular material flows . Advances in battery technologies could
    facilitate the electrification of heavy-duty trucks and compliment conventional
    electric rail systems. Sustainable biofuels can offer additional mitigation benefits
    in land-based transport in the short and medium term. Sustainable biofuels, low-emissions
    hydrogen, and derivatives can support mitigation of CO2 emissions from shipping,
    aviation, and heavy-duty land transport but require production process improvements
    and cost reductions. Key infrastructure systems including sanitation, water, health,
    transport, communications and energy will be increasingly vulnerable if design
    standards do not account for changing climate conditions.  Green/natural and blue
    infrastructure such as urban forestry, green roofs, ponds and lakes, and river
    restoration can mitigate climate change through carbon uptake and storage, avoided
    emissions, and reduced energy use while reducing risk from extreme events such
    as heatwaves, heavy precipitation and droughts, and advancing co-benefits for
    health, well-being and livelihoods. Urban greening can provide local cooling.
    Combining green/natural and grey/physical infrastructure adaptation responses
    has potential to reduce adaptation costs and contribute to flood control, sanitation,
    water resources management, landslide prevention and coastal protection. Globally,
    more financing is directed at grey/physical infrastructure than green/natural
    infrastructure and social infrastructure, and there is limited evidence of investment
    in informal settlements . The greatest gains in well-being in urban areas can
    be achieved by prioritising finance to reduce climate risk for low-income and
    marginalised communities including people living in informal settlements.  Responses
    to ongoing sea level rise and land subsidence in low-lying coastal cities and
    settlements and small islands include protection, accommodation, advance and planned
    relocation. These responses are more effective if combined and/or sequenced, planned
    well ahead, aligned with sociocultural values and development priorities, and
    underpinned by inclusive community engagement processes. '
  C.3.5:
  - Land, Ocean, Food, and Water  There is substantial mitigation and adaptation potential
    from options in agriculture, forestry and other land use, and in the oceans, that
    could be upscaled in the near term across most regions. Conservation, improved
    management, and restoration of forests and other ecosystems offer the largest
    share of economic mitigation potential, with reduced deforestation in tropical
    regions having the highest total mitigation potential. Ecosystem restoration,
    reforestation, and afforestation can lead to trade-offs due to competing demands
    on land. Minimizing trade-offs requires integrated approaches to meet multiple
    objectives including food security. Demand-side measures  and sustainable agricultural
    intensification can reduce ecosystem conversion and CH4 and N2 O emissions, and
    free up land for reforestation and ecosystem restoration. Sustainably sourced
    agriculture and forest products, including long-lived wood products, can be used
    instead of more GHG-intensive products in other sectors. Effective adaptation
    options include cultivar improvements, agroforestry, community-based adaptation,
    farm and landscape diversification, and urban agriculture. These AFOLU response
    options require integration of biophysical, socioeconomic and other enabling factors.
    The effectiveness of ecosystem-based adaptation and most water-related adaptation
    options declines with increasing warming.  Some options, such as conservation
    of high-carbon ecosystems , have immediate impacts while others, such as restoration
    of high-carbon ecosystems, reclamation of degraded soils or afforestation, take
    decades to deliver measurable results. Many sustainable land management technologies
    and practices are financially profitable in three to ten years.  Maintaining the
    resilience of biodiversity and ecosystem services at a global scale depends on
    effective and equitable conservation of approximately 30–50% of Earth’s land,
    freshwater and ocean areas, including currently near-natural ecosystems. The services
    and options provided by terrestrial, freshwater, coastal and ocean ecosystems
    can be supported by protection, restoration, precautionary ecosystem-based management
    of renewable resource use, and the reduction of pollution and other stressors.  Large-scale
    land conversion for bioenergy, biochar, or afforestation can increase risks to
    biodiversity, water and food security. In contrast, restoring natural forests
    and drained peatlands, and improving sustainability of managed forests enhances
    the resilience of carbon stocks and sinks and reduces ecosystem vulnerability
    to climate change. Cooperation, and inclusive decision making, with local communities
    and Indigenous Peoples, as well as recognition of inherent rights of Indigenous
    Peoples, is integral to successful adaptation across forests and other ecosystems.  Natural
    rivers, wetlands and upstream forests reduce flood risk in most circumstances.
    Enhancing natural water retention such as by restoring wetlands and rivers, land
    use planning such as no build zones or upstream forest management, can further
    reduce flood risk . For inland flooding, combinations of non-structural measures
    like early warning systems and structural measures like levees have reduced loss
    of lives, but hard defences against flooding or sea level rise can also be maladaptive
    .  Protection and restoration of coastal ‘blue carbon’ ecosystems could reduce
    emissions and/or increase carbon uptake and storage . Coastal wetlands protect
    against coastal erosion and flooding. Strengthening precautionary approaches,
    such as rebuilding overexploited or depleted fisheries, and responsiveness of
    existing fisheries management strategies reduces negative climate change impacts
    on fisheries, with benefits for regional economies and livelihoods. Ecosystem-based
    management in fisheries and aquaculture supports food security, biodiversity,
    human health and well-being.
  C.3.6:
  - Land, Ocean, Food, and Water  There is substantial mitigation and adaptation potential
    from options in agriculture, forestry and other land use, and in the oceans, that
    could be upscaled in the near term across most regions. Conservation, improved
    management, and restoration of forests and other ecosystems offer the largest
    share of economic mitigation potential, with reduced deforestation in tropical
    regions having the highest total mitigation potential. Ecosystem restoration,
    reforestation, and afforestation can lead to trade-offs due to competing demands
    on land. Minimizing trade-offs requires integrated approaches to meet multiple
    objectives including food security. Demand-side measures  and sustainable agricultural
    intensification can reduce ecosystem conversion and CH4 and N2 O emissions, and
    free up land for reforestation and ecosystem restoration. Sustainably sourced
    agriculture and forest products, including long-lived wood products, can be used
    instead of more GHG-intensive products in other sectors. Effective adaptation
    options include cultivar improvements, agroforestry, community-based adaptation,
    farm and landscape diversification, and urban agriculture. These AFOLU response
    options require integration of biophysical, socioeconomic and other enabling factors.
    The effectiveness of ecosystem-based adaptation and most water-related adaptation
    options declines with increasing warming.  Some options, such as conservation
    of high-carbon ecosystems , have immediate impacts while others, such as restoration
    of high-carbon ecosystems, reclamation of degraded soils or afforestation, take
    decades to deliver measurable results. Many sustainable land management technologies
    and practices are financially profitable in three to ten years.  Maintaining the
    resilience of biodiversity and ecosystem services at a global scale depends on
    effective and equitable conservation of approximately 30–50% of Earth’s land,
    freshwater and ocean areas, including currently near-natural ecosystems. The services
    and options provided by terrestrial, freshwater, coastal and ocean ecosystems
    can be supported by protection, restoration, precautionary ecosystem-based management
    of renewable resource use, and the reduction of pollution and other stressors.  Large-scale
    land conversion for bioenergy, biochar, or afforestation can increase risks to
    biodiversity, water and food security. In contrast, restoring natural forests
    and drained peatlands, and improving sustainability of managed forests enhances
    the resilience of carbon stocks and sinks and reduces ecosystem vulnerability
    to climate change. Cooperation, and inclusive decision making, with local communities
    and Indigenous Peoples, as well as recognition of inherent rights of Indigenous
    Peoples, is integral to successful adaptation across forests and other ecosystems.  Natural
    rivers, wetlands and upstream forests reduce flood risk in most circumstances.
    Enhancing natural water retention such as by restoring wetlands and rivers, land
    use planning such as no build zones or upstream forest management, can further
    reduce flood risk . For inland flooding, combinations of non-structural measures
    like early warning systems and structural measures like levees have reduced loss
    of lives, but hard defences against flooding or sea level rise can also be maladaptive
    .  Protection and restoration of coastal ‘blue carbon’ ecosystems could reduce
    emissions and/or increase carbon uptake and storage . Coastal wetlands protect
    against coastal erosion and flooding. Strengthening precautionary approaches,
    such as rebuilding overexploited or depleted fisheries, and responsiveness of
    existing fisheries management strategies reduces negative climate change impacts
    on fisheries, with benefits for regional economies and livelihoods. Ecosystem-based
    management in fisheries and aquaculture supports food security, biodiversity,
    human health and well-being.
  - 'Co-Benefits of Adaptation and Mitigation for Sustainable Development Goals  Mitigation
    and adaptation actions have more synergies than trade-offs with Sustainable Development
    Goals . Synergies and trade-offs depend on context and scale of implementation.
    Potential trade-offs can be compensated or avoided with additional policies, investments
    and financial partnerships. Many mitigation and adaptation actions have multiple
    synergies with Sustainable Development Goals, but some actions can also have trade-offs.
    Potential synergies with SDGs exceed potential trade-offs. Synergies and trade-offs
    are context specific and depend on: means and scale of implementation, intra-
    and inter-sectoral interactions, cooperation between countries and regions, the
    sequencing, timing and stringency of actions, governance, and policy design. Eradicating
    extreme poverty, energy poverty, and providing decent living standards to all,
    consistent with nearterm sustainable development objectives, can be achieved without
    significant global emissions growth.  Several mitigation and adaptation options
    can harness nearterm synergies and reduce trade-offs to advance sustainable development
    in energy, urban and land systems . Clean energy supply systems have multiple
    co-benefits, including improvements in air quality and health. Heat Health Action
    Plans that include early warning and response systems, approaches that mainstream
    health into food, livelihoods, social protection, water and sanitation benefit
    health and wellbeing. There are potential synergies between multiple Sustainable
    Development Goals and sustainable land use and urban planning with more green
    spaces, reduced air pollution, and demand-side mitigation including shifts to
    balanced, sustainable healthy diets. Electrification combined with low-GHG energy,
    and shifts to public transport can enhance health, employment, and can contribute
    to energy security and deliver equity. Conservation, protection and restoration
    of terrestrial, freshwater, coastal and ocean ecosystems, together with targeted
    management to adapt to unavoidable impacts of climate change can generate multiple
    additional benefits, such as agricultural productivity, food security, and biodiversity
    conservation.  When implementing mitigation and adaptation together, and taking
    trade-offs into account, multiple co-benefits and synergies for human well-being
    as well as ecosystem and planetary health can be realised. There is a strong link
    between sustainable development, vulnerability and climate risks. Social safety
    nets that support climate change adaptation have strong co-benefits with development
    goals such as education, poverty alleviation, gender inclusion and food security.
    Land restoration contributes to mitigation and adaptation with synergies via enhanced
    ecosystem services and with economically positive returns and co-benefits for
    poverty reduction and improved livelihoods. Trade-offs can be evaluated and minimised
    by giving emphasis to capacity building, finance, technology transfer, investments;
    governance, development, context specific gender-based and other social equity
    considerations with meaningful participation of Indigenous Peoples, local communities
    and vulnerable populations. .  Context relevant design and implementation requires
    considering people’s needs, biodiversity, and other sustainable development dimensions.
    Countries at all stages of economic development seek to improve the well-being
    of people, and their development priorities reflect different starting points
    and contexts. Different contexts include but are not limited to social, economic,
    environmental, cultural, or political circumstances, resource endowment, capabilities,
    international environment, and prior development. n regions with high dependency
    on fossil fuels for, among other things, revenue and employment generation, mitigating
    risks for sustainable development requires policies that promote economic and
    energy sector diversification and considerations of just transitions principles,
    processes and practices. For individuals and households in low-lying coastal areas,
    in Small Islands, and smallholder farmers transitioning from incremental to transformational
    adaptation can help overcome soft adaptation limits. Effective governance is needed
    to limit trade-offs of some mitigation options such as large scale afforestation
    and bioenergy options due to risks from their deployment for food systems, biodiversity,
    other ecosystem functions and services, and livelihoods. Effective governance
    requires adequate institutional capacity at all levels .'
  C.3.7:
  - Health and Nutrition  Human health will benefit from integrated mitigation and
    adaptation options that mainstream health into food, infrastructure, social protection,
    and water policies . Balanced and sustainable healthy diets and reduced food loss
    and waste present important opportunities for adaptation and mitigation while
    generating significant co-benefits in terms of biodiversity and human health.
    Public health policies to improve nutrition, such as increasing the diversity
    of food sources in public procurement, health insurance, financial incentives,
    and awareness-raising campaigns, can potentially influence food demand, reduce
    food waste, reduce healthcare costs, contribute to lower GHG emissions and enhance
    adaptive capacity. Improved access to clean energy sources and technologies, and
    shifts to active mobility and public transport can deliver socioeconomic, air
    quality and health benefits, especially for women and children.  Effective adaptation
    options exist to help protect human health and well-being. Health Action Plans
    that include early warning and response systems are effective for extreme heat
    . Effective options for water-borne and food-borne diseases include improving
    access to potable water, reducing exposure of water and sanitation systems to
    flooding and extreme weather events, and improved early warning systems. For vector-borne
    diseases, effective adaptation options include surveillance, early warning systems,
    and vaccine development. Effective adaptation options for reducing mental health
    risks under climate change include improving surveillance and access to mental
    health care, and monitoring of psychosocial impacts from extreme weather events.
    A key pathway to climate resilience in the health sector is universal access to
    healthcare.
  C.3.8:
  - Society, Livelihoods, and Economies  Enhancing knowledge on risks and available
    adaptation options promotes societal responses, and behaviour and lifestyle changes
    supported by policies, infrastructure and technology can help reduce global GHG
    emissions. Climate literacy and information provided through climate services
    and community approaches, including those that are informed by Indigenous Knowledge
    and local knowledge, can accelerate behavioural changes and planning . Educational
    and information programmes, using the arts, participatory modelling and citizen
    science can facilitate awareness, heighten risk perception, and influence behaviours
    . The way choices are presented can enable adoption of low GHG intensive socio-cultural
    options, such as shifts to balanced, sustainable healthy diets, reduced food waste,
    and active mobility. Judicious labelling, framing, and communication of social
    norms can increase the effect of mandates, subsidies, or taxes.  A range of adaptation
    options, such as disaster risk management, early warning systems, climate services
    and risk spreading and sharing approaches, have broad applicability across sectors
    and provide greater risk reduction benefits when combined . Climate services that
    are demand-driven and inclusive of different users and providers can improve agricultural
    practices, inform better water use and efficiency, and enable resilient infrastructure
    planning. Policy mixes that include weather and health insurance, social protection
    and adaptive safety nets, contingent finance and reserve funds, and universal
    access to early warning systems combined with effective contingency plans, can
    reduce vulnerability and exposure of human systems. Integrating climate adaptation
    into social protection programs, including cash transfers and public works programs,
    is highly feasible and increases resilience to climate change, especially when
    supported by basic services and infrastructure. Social safety nets can build adaptive
    capacities, reduce socioeconomic vulnerability, and reduce risk linked to hazards.  Reducing
    future risks of involuntary migration and displacement due to climate change is
    possible through cooperative, international efforts to enhance institutional adaptive
    capacity and sustainable development. Increasing adaptive capacity minimises risk
    associated with involuntary migration and immobility and improves the degree of
    choice under which migration decisions are made, while policy interventions can
    remove barriers and expand the alternatives for safe, orderly and regular migration
    that allows vulnerable people to adapt to climate change.  Accelerating commitment
    and follow-through by the private sector is promoted for instance by building
    business cases for adaptation, accountability and transparency mechanisms, and
    monitoring and evaluation of adaptation progress . Integrated pathways for managing
    climate risks will be most suitable when so-called ‘low-regret’ anticipatory options
    are established jointly across sectors in a timely manner and are feasible and
    effective in their local context, and when path dependencies and maladaptations
    across sectors are avoided. Sustained adaptation actions are strengthened by mainstreaming
    adaptation into institutional budget and policy planning cycles, statutory planning,
    monitoring and evaluation frameworks and into recovery efforts from disaster events.
    Instruments that incorporate adaptation such as policy and legal frameworks, behavioural
    incentives, and economic instruments that address market failures, such as climate
    risk disclosure, inclusive and deliberative processes strengthen adaptation actions
    by public and private actors.
  C.4.1:
  - Equity and Inclusion in Climate Change Action  Actions that prioritise equity,
    climate justice, social justice and inclusion lead to more sustainable outcomes,
    co-benefits, reduce trade-offs, support transformative change and advance climate
    resilient development. Adaptation responses are immediately needed to reduce rising
    climate risks, especially for the most vulnerable. Equity, inclusion and just
    transitions are key to progress on adaptation and deeper societal ambitions for
    accelerated mitigation. Adaptation and mitigation actions, across scales, sectors
    and regions, that prioritise equity, climate justice, rights-based approaches,
    social justice and inclusivity, lead to more sustainable outcomes, reduce trade-offs,
    support transformative change and advance climate resilient development . Redistributive
    policies across sectors and regions that shield the poor and vulnerable, social
    safety nets, equity, inclusion and just transitions, at all scales can enable
    deeper societal ambitions and resolve trade-offs with sustainable development
    goals., particularly education, hunger, poverty, gender and energy access . Mitigation
    efforts embedded within the wider development context can increase the pace, depth
    and breadth of emission reductions . Equity, inclusion and just transitions at
    all scales enable deeper societal ambitions for accelerated mitigation, and climate
    action more broadly. The complexity in risk of rising food prices, reduced household
    incomes, and health and climate-related malnutrition  and mortality increases
    with little or low levels of adaptation.  Regions and people with considerable
    development constraints have high vulnerability to climatic hazards. Adaptation
    outcomes for the most vulnerable within and across countries and regions are enhanced
    through approaches focusing on equity, inclusivity, and rights-based approaches,
    including 3.3 to 3.6 billion people living in contexts that are highly vulnerable
    to climate change. Vulnerability is higher in locations with poverty, governance
    challenges and limited access to basic services and resources, violent conflict
    and high levels of climate-sensitive livelihoods  . Several risks can be moderated
    with adaptation. The largest adaptation gaps exist among lower income population
    groups and adaptation progress is unevenly distributed with observed adaptation
    gaps. Present development challenges causing high vulnerability are influenced
    by historical and ongoing patterns of inequity such as colonialism, especially
    for many Indigenous Peoples and local communities. Vulnerability is exacerbated
    by inequity and marginalisation linked to gender, ethnicity, low income or combinations
    thereof, especially for many Indigenous Peoples and local communities.  Meaningful
    participation and inclusive planning, informed by cultural values, Indigenous
    Knowledge, local knowledge, and scientific knowledge can help address adaptation
    gaps and avoid maladaptation. Such actions with flexible pathways may encourage
    low-regret and timely actions . Integrating climate adaptation into social protection
    programmes, including cash transfers and public works programmes, would increase
    resilience to climate change, especially when supported by basic services and
    infrastructure.  Equity, inclusion, just transitions, broad and meaningful participation
    of all relevant actors in decision making at all scales enable deeper societal
    ambitions for accelerated mitigation, and climate action more broadly, and build
    social trust, support transformative changes and an equitable sharing of benefits
    and burdens. Equity remains a central element in the UN climate regime, notwithstanding
    shifts in differentiation between states over time and challenges in assessing
    fair shares. Ambitious mitigation pathways imply large and sometimes disruptive
    changes in economic structure, with significant distributional consequences, within
    and between countries, including shifting of income and employment during the
    transition from high to low emissions activities. While some jobs may be lost,
    low-emissions development can also open up opportunities to enhance skills and
    create jobs. Broadening equitable access to finance, technologies and governance
    that facilitate mitigation, and consideration of climate justice can help equitable
    sharing of benefits and burdens, especially for vulnerable countries and communities.  Development
    priorities among countries also reflect different starting points and contexts,
    and enabling conditions for shifting development pathways towards increased sustainability
    will therefore differ, giving rise to different needs . Implementing just transition
    principles through collective and participatory decision-making processes is an
    effective way of integrating equity principles into policies at all scales depending
    on national circumstances, while in several countries just transition commissions,
    task forces and national policies have been established .  Many economic and regulatory
    instruments have been effective in reducing emissions and practical experience
    has informed instrument design to improve them while addressing distributional
    goals and social acceptance. The design of behavioural interventions, including
    the way that choices are presented to consumers work synergistically with price
    signals, making the combination more effective. Individuals with high socio-economic
    status contribute disproportionately to emissions, and have the highest potential
    for emissions reductions, e.g., as citizens, investors, consumers, role models,
    and professionals . There are options on design of instruments such as taxes,
    subsidies, prices, and consumption-based approaches, complemented by regulatory
    instruments to reduce high-emissions consumption while improving equity and societal
    well-being. Behaviour and lifestyle changes to help end-users adopt low-GHG-intensive
    options can be supported by policies, infrastructure and technology with multiple
    co-benefits for societal well-being. Broadening equitable access to domestic and
    international finance, technologies and capacity can also act as a catalyst for
    accelerating mitigation and shifting development pathways in low-income contexts
    . Eradicating extreme poverty, energy poverty, and providing decent living standards
    to all in these regions in the context of achieving sustainable development objectives,
    in the near term, can be achieved without significant global emissions growth.
    Technology development, transfer, capacity building and financing can support
    developing countries/ regions leapfrogging or transitioning to low-emissions transport
    systems thereby providing multiple co-benefits . Climate resilient development
    is advanced when actors work in equitable, just and enabling ways to reconcile
    divergent interests, values and worldviews, toward equitable and just outcomes
    .
  - 'Co-Benefits of Adaptation and Mitigation for Sustainable Development Goals  Mitigation
    and adaptation actions have more synergies than trade-offs with Sustainable Development
    Goals . Synergies and trade-offs depend on context and scale of implementation.
    Potential trade-offs can be compensated or avoided with additional policies, investments
    and financial partnerships. Many mitigation and adaptation actions have multiple
    synergies with Sustainable Development Goals, but some actions can also have trade-offs.
    Potential synergies with SDGs exceed potential trade-offs. Synergies and trade-offs
    are context specific and depend on: means and scale of implementation, intra-
    and inter-sectoral interactions, cooperation between countries and regions, the
    sequencing, timing and stringency of actions, governance, and policy design. Eradicating
    extreme poverty, energy poverty, and providing decent living standards to all,
    consistent with nearterm sustainable development objectives, can be achieved without
    significant global emissions growth.  Several mitigation and adaptation options
    can harness nearterm synergies and reduce trade-offs to advance sustainable development
    in energy, urban and land systems . Clean energy supply systems have multiple
    co-benefits, including improvements in air quality and health. Heat Health Action
    Plans that include early warning and response systems, approaches that mainstream
    health into food, livelihoods, social protection, water and sanitation benefit
    health and wellbeing. There are potential synergies between multiple Sustainable
    Development Goals and sustainable land use and urban planning with more green
    spaces, reduced air pollution, and demand-side mitigation including shifts to
    balanced, sustainable healthy diets. Electrification combined with low-GHG energy,
    and shifts to public transport can enhance health, employment, and can contribute
    to energy security and deliver equity. Conservation, protection and restoration
    of terrestrial, freshwater, coastal and ocean ecosystems, together with targeted
    management to adapt to unavoidable impacts of climate change can generate multiple
    additional benefits, such as agricultural productivity, food security, and biodiversity
    conservation.  When implementing mitigation and adaptation together, and taking
    trade-offs into account, multiple co-benefits and synergies for human well-being
    as well as ecosystem and planetary health can be realised. There is a strong link
    between sustainable development, vulnerability and climate risks. Social safety
    nets that support climate change adaptation have strong co-benefits with development
    goals such as education, poverty alleviation, gender inclusion and food security.
    Land restoration contributes to mitigation and adaptation with synergies via enhanced
    ecosystem services and with economically positive returns and co-benefits for
    poverty reduction and improved livelihoods. Trade-offs can be evaluated and minimised
    by giving emphasis to capacity building, finance, technology transfer, investments;
    governance, development, context specific gender-based and other social equity
    considerations with meaningful participation of Indigenous Peoples, local communities
    and vulnerable populations. .  Context relevant design and implementation requires
    considering people’s needs, biodiversity, and other sustainable development dimensions.
    Countries at all stages of economic development seek to improve the well-being
    of people, and their development priorities reflect different starting points
    and contexts. Different contexts include but are not limited to social, economic,
    environmental, cultural, or political circumstances, resource endowment, capabilities,
    international environment, and prior development. n regions with high dependency
    on fossil fuels for, among other things, revenue and employment generation, mitigating
    risks for sustainable development requires policies that promote economic and
    energy sector diversification and considerations of just transitions principles,
    processes and practices. For individuals and households in low-lying coastal areas,
    in Small Islands, and smallholder farmers transitioning from incremental to transformational
    adaptation can help overcome soft adaptation limits. Effective governance is needed
    to limit trade-offs of some mitigation options such as large scale afforestation
    and bioenergy options due to risks from their deployment for food systems, biodiversity,
    other ecosystem functions and services, and livelihoods. Effective governance
    requires adequate institutional capacity at all levels .'
  C.4.2:
  - Synergies and trade-offs, costs and benefits  Mitigation and adaptation options
    can lead to synergies and trade-offs with other aspects of sustainable development
    . Synergies and trade-offs depend on the pace and magnitude of changes and the
    development context including inequalities, with consideration of climate justice.
    The potential or effectiveness of some adaptation and mitigation options decreases
    as climate change intensifies .  In the energy sector, transitions to low-emission
    systems will have multiple co-benefits, including improvements in air quality
    and health. There are potential synergies between sustainable development and,
    for instance, energy efficiency and renewable energy.  For agriculture, land,
    and food systems, many land management options and demand-side response options  can
    contribute to eradicating poverty and eliminating hunger while promoting good
    health and well-being, clean water and sanitation, and life on land . In contrast,
    certain adaptation options that promote intensification of production, such as
    irrigation, may have negative effects on sustainability  .  Reforestation, improved
    forest management, soil carbon sequestration, peatland restoration and coastal
    blue carbon management are examples of CDR methods that can enhance biodiversity
    and ecosystem functions, employment and local livelihoods, depending on context
    . However, afforestation or production of biomass crops for bioenergy with carbon
    dioxide capture and storage or biochar can have adverse socio-economic and environmental
    impacts, including on biodiversity, food and water security, local livelihoods
    and the rights of Indigenous Peoples, especially if implemented at large scales
    and where land tenure is insecure.  Modelled pathways that assume using resources
    more efficiently or shift global development towards sustainability include fewer
    challenges, such as dependence on CDR and pressure on land and biodiversity, and
    have the most pronounced synergies with respect to sustainable development .  Strengthening
    climate change mitigation action entails more rapid transitions and higher up-front
    investments, but brings benefits from avoiding damages from climate change and
    reduced adaptation costs. The aggregate effects of climate change mitigation on
    global GDP  are small compared to global projected GDP growth. Projected estimates
    of global aggregate net economic damages and the costs of adaptation generally
    increase with global warming level.  Cost-benefit analysis remains limited in
    its ability to represent all damages from climate change, including non-monetary
    damages, or to capture the heterogeneous nature of damages and the risk of catastrophic
    damages. Even without accounting for these factors or for the co-benefits of mitigation,
    the global benefits of limiting warming to 2°C exceed the cost of mitigation .
    This finding is robust against a wide range of assumptions about social preferences
    on inequalities and discounting over time . Limiting global warming to 1.5°C instead
    of 2°C would increase the costs of mitigation, but also increase the benefits
    in terms of reduced impacts and related risks and reduced adaptation needs 140.  Considering
    other sustainable development dimensions, such as the potentially strong economic
    benefits on human health from air quality improvement, may enhance the estimated
    benefits of mitigation . The economic effects of strengthened mitigation action
    vary across regions and countries, depending notably on economic structure, regional
    emissions reductions, policy design and level of international cooperation. Ambitious
    mitigation pathways imply large and sometimes disruptive changes in economic structure,
    with implications for near-term actions, equity , sustainability, and finance
    .
  - 'Co-Benefits of Adaptation and Mitigation for Sustainable Development Goals  Mitigation
    and adaptation actions have more synergies than trade-offs with Sustainable Development
    Goals . Synergies and trade-offs depend on context and scale of implementation.
    Potential trade-offs can be compensated or avoided with additional policies, investments
    and financial partnerships. Many mitigation and adaptation actions have multiple
    synergies with Sustainable Development Goals, but some actions can also have trade-offs.
    Potential synergies with SDGs exceed potential trade-offs. Synergies and trade-offs
    are context specific and depend on: means and scale of implementation, intra-
    and inter-sectoral interactions, cooperation between countries and regions, the
    sequencing, timing and stringency of actions, governance, and policy design. Eradicating
    extreme poverty, energy poverty, and providing decent living standards to all,
    consistent with nearterm sustainable development objectives, can be achieved without
    significant global emissions growth.  Several mitigation and adaptation options
    can harness nearterm synergies and reduce trade-offs to advance sustainable development
    in energy, urban and land systems . Clean energy supply systems have multiple
    co-benefits, including improvements in air quality and health. Heat Health Action
    Plans that include early warning and response systems, approaches that mainstream
    health into food, livelihoods, social protection, water and sanitation benefit
    health and wellbeing. There are potential synergies between multiple Sustainable
    Development Goals and sustainable land use and urban planning with more green
    spaces, reduced air pollution, and demand-side mitigation including shifts to
    balanced, sustainable healthy diets. Electrification combined with low-GHG energy,
    and shifts to public transport can enhance health, employment, and can contribute
    to energy security and deliver equity. Conservation, protection and restoration
    of terrestrial, freshwater, coastal and ocean ecosystems, together with targeted
    management to adapt to unavoidable impacts of climate change can generate multiple
    additional benefits, such as agricultural productivity, food security, and biodiversity
    conservation.  When implementing mitigation and adaptation together, and taking
    trade-offs into account, multiple co-benefits and synergies for human well-being
    as well as ecosystem and planetary health can be realised. There is a strong link
    between sustainable development, vulnerability and climate risks. Social safety
    nets that support climate change adaptation have strong co-benefits with development
    goals such as education, poverty alleviation, gender inclusion and food security.
    Land restoration contributes to mitigation and adaptation with synergies via enhanced
    ecosystem services and with economically positive returns and co-benefits for
    poverty reduction and improved livelihoods. Trade-offs can be evaluated and minimised
    by giving emphasis to capacity building, finance, technology transfer, investments;
    governance, development, context specific gender-based and other social equity
    considerations with meaningful participation of Indigenous Peoples, local communities
    and vulnerable populations. .  Context relevant design and implementation requires
    considering people’s needs, biodiversity, and other sustainable development dimensions.
    Countries at all stages of economic development seek to improve the well-being
    of people, and their development priorities reflect different starting points
    and contexts. Different contexts include but are not limited to social, economic,
    environmental, cultural, or political circumstances, resource endowment, capabilities,
    international environment, and prior development. n regions with high dependency
    on fossil fuels for, among other things, revenue and employment generation, mitigating
    risks for sustainable development requires policies that promote economic and
    energy sector diversification and considerations of just transitions principles,
    processes and practices. For individuals and households in low-lying coastal areas,
    in Small Islands, and smallholder farmers transitioning from incremental to transformational
    adaptation can help overcome soft adaptation limits. Effective governance is needed
    to limit trade-offs of some mitigation options such as large scale afforestation
    and bioenergy options due to risks from their deployment for food systems, biodiversity,
    other ecosystem functions and services, and livelihoods. Effective governance
    requires adequate institutional capacity at all levels .'
  - Integration of Near-Term Actions Across Sectors and Systems  The feasibility,
    effectiveness and benefits of mitigation and adaptation actions are increased
    when multi-sectoral solutions are undertaken that cut across systems. When such
    options are combined with broader sustainable development objectives, they can
    yield greater benefits for human well-being, social equity and justice, and ecosystem
    and planetary health. Climate resilient development strategies that treat climate,
    ecosystems and biodiversity, and human society as parts of an integrated system
    are the most effective. Human and ecosystem vulnerability are interdependent.
    Climate resilient development is enabled when decision-making processes and actions
    are integrated across sectors. Synergies with and progress towards the Sustainable
    Development Goals enhance prospects for climate resilient development. Choices
    and actions that treat humans and ecosystems as an integrated system build on
    diverse knowledge about climate risk, equitable, just and inclusive approaches,
    and ecosystem stewardship.  Approaches that align goals and actions across sectors
    provide opportunities for multiple and large-scale benefits and avoided damages
    in the near term. Such measures can also achieve greater benefits through cascading
    effects across sectors . For example, the feasibility of using land for both agriculture
    and centralised solar production can increase when such options are combined.
    Similarly, integrated transport and energy infrastructure planning and operations
    can together reduce the environmental, social, and economic impacts of decarbonising
    the transport and energy sectors. The implementation of packages of multiple city-scale
    mitigation strategies can have cascading effects across sectors and reduce GHG
    emissions both within and outside a city’s administrative boundaries . Integrated
    design approaches to the construction and retrofit of buildings provide increasing
    examples of zero energy or zero carbon buildings in several regions. To minimise
    maladaptation, multi-sectoral, multi-actor and inclusive planning with flexible
    pathways encourages low-regret and timely actions that keep options open, ensure
    benefits in multiple sectors and systems and suggest the available solution space
    for adapting to long-term climate change . Trade-offs in terms of employment,
    water use, land-use competition and biodiversity, as well as access to, and the
    affordability of, energy, food, and water can be avoided by well-implemented land-based
    mitigation options, especially those that do not threaten existing sustainable
    land uses and land rights, with frameworks for integrated policy implementation.  Mitigation
    and adaptation when implemented together, and combined with broader sustainable
    development objectives, would yield multiple benefits for human well-being as
    well as ecosystem and planetary health. The range of such positive interactions
    is significant in the landscape of near-term climate policies across regions,
    sectors and systems. For example, AFOLU mitigation actions in land-use change
    and forestry, when sustainably implemented, can provide large-scale GHG emission
    reductions and removals that simultaneously benefit biodiversity, food security,
    wood supply and other ecosystem services but cannot fully compensate for delayed
    mitigation action in other sectors. Adaptation measures in land, ocean and ecosystems
    similarly can have widespread benefits for food security, nutrition, health and
    well-being, ecosystems and biodiversity. Equally, urban systems are critical,
    interconnected sites for climate resilient development; urban policies that implement
    multiple interventions can yield adaptation or mitigation gains with equity and
    human well-being. Integrated policy packages can improve the ability to integrate
    considerations of equity, gender equality and justice. Coordinated cross-sectoral
    policies and planning can maximise synergies and avoid or reduce trade-offs between
    mitigation and adaptation. Effective action in all of the above areas will require
    near-term political commitment and follow-through, social cooperation, finance,
    and more integrated cross-sectoral policies and support and actions. .
  C.4.3:
  - 'Benefits of Strengthening Near-Term Action  Accelerated implementation of adaptation
    will improve well-being by reducing losses and damages, especially for vulnerable
    populations. Deep, rapid, and sustained mitigation actions would reduce future
    adaptation costs and losses and damages, enhance sustainable development co-benefits,
    avoid locking-in emission sources, and reduce stranded assets and irreversible
    climate changes. These near-term actions involve higher up-front investments and
    disruptive changes, which can be moderated by a range of enabling conditions and
    removal or reduction of barriers to feasibility. Accelerated implementation of
    adaptation responses will bring benefits to human well-being. As adaptation options
    often have long implementation times, long-term planning and accelerated implementation,
    particularly in this decade, is important to close adaptation gaps, recognising
    that constraints remain for some regions. The benefits to vulnerable populations
    would be high .  Near-term actions that limit global warming to close to 1.5°C
    would substantially reduce projected losses and damages related to climate change
    in human systems and ecosystems, compared to higher warming levels, but cannot
    eliminate them all . The magnitude and rate of climate change and associated risks
    depend strongly on near-term mitigation and adaptation actions, and projected
    adverse impacts and related losses and damages escalate with every increment of
    global warming. Delayed mitigation action will further increase global warming
    which will decrease the effectiveness of many adaptation options, including Ecosystem-based
    Adaptation and many water-related options, as well as increasing mitigation feasibility
    risks, such as for options based on ecosystems. Comprehensive, effective, and
    innovative responses integrating adaptation and mitigation can harness synergies
    and reduce trade-offs between adaptation and mitigation, as well as in meeting
    requirements for financing .  Mitigation actions will have other sustainable development
    co-benefits. Mitigation will improve air quality and human health in the near
    term notably because many air pollutants are co-emitted by GHG emitting sectors
    and because methane emissions leads to surface ozone formation. The benefits from
    air quality improvement include prevention of air pollution-related premature
    deaths, chronic diseases and damages to ecosystems and crops. The economic benefits
    for human health from air quality improvement arising from mitigation action can
    be of the same order of magnitude as mitigation costs, and potentially even larger
    . As methane has a short lifetime but is a potent GHG, strong, rapid and sustained
    reductions in methane emissions can limit near-term warming and improve air quality
    by reducing global surface ozone.  Challenges from delayed adaptation and mitigation
    actions include the risk of cost escalation, lock-in of infrastructure, stranded
    assets, and reduced feasibility and effectiveness of adaptation and mitigation
    options. The continued installation of unabated fossil fuel infrastructure will
    ‘lock-in’ GHG emissions. Limiting global warming to 2°C or below will leave a
    substantial amount of fossil fuels unburned and could strand considerable fossil
    fuel infrastructure , with globally discounted value projected to be around USD
    1 to 4 trillion from 2015 to 2050. Early actions would limit the size of these
    stranded assets, whereas delayed actions with continued investments in unabated
    high-emitting infrastructure and limited development and deployment of low-emitting
    alternatives prior to 2030 would raise future stranded assets to the higher end
    of the range – thereby acting as barriers and increasing political economy feasibility
    risks that may jeopardise efforts to limit global warming. .  Scaling-up near-term
    climate actions will mobilise a mix of low-cost and high-cost options. High-cost
    options, as in energy and infrastructure, are needed to avoid future lock-ins,
    foster innovation and initiate transformational changes. Climate resilient development
    pathways in support of sustainable development for all are shaped by equity, and
    social and climate justice. Embedding effective and equitable adaptation and mitigation
    in development planning can reduce vulnerability, conserve and restore ecosystems,
    and enable climate resilient development. This is especially challenging in localities
    with persistent development gaps and limited resources.  Scaling-up climate action
    may generate disruptive changes in economic structure with distributional consequences
    and need to reconcile divergent interests, values and worldviews, within and between
    countries. Deeper fiscal, financial, institutional and regulatory reforms can
    offset such adverse effects and unlock mitigation potentials. Societal choices
    and actions implemented in this decade will determine the extent to which medium
    and long-term development pathways will deliver higher or lower climate resilient
    development outcomes.  Enabling conditions would need to be strengthened in the
    nearterm and barriers reduced or removed to realise opportunities for deep and
    rapid adaptation and mitigation actions and climate resilient development. These
    enabling conditions are differentiated by national, regional and local circumstances
    and geographies, according to capabilities, and include: equity and inclusion
    in climate action, rapid and far-reaching transitions in sectors and system ,
    measures to achieve synergies and reduce tradeoffs with sustainable development
    goals, governance and policy improvements, access to finance, improved international
    cooperation and technology improvements, and integration of near-term actions
    across sectors, systems and regions.  Barriers to feasibility would need to be
    reduced or removed to deploy mitigation and adaptation options at scale. Many
    limits to feasibility and effectiveness of responses can be overcome by addressing
    a range of barriers, including economic, technological, institutional, social,
    environmental and geophysical barriers. The feasibility and effectiveness of options
    increase with integrated, multi-sectoral solutions that differentiate responses
    based on climate risk, cut across systems and address social inequities. Strengthened
    near-term actions in modelled cost-effective pathways that limit global warming
    to 2°C or lower, reduce the overall risk to the feasibility of the system transitions,
    compared to modelled pathways with delayed or uncoordinated action.  Integrating
    ambitious climate actions with macroeconomic policies under global uncertainty
    would provide benefits . This encompasses three main directions: economy-wide
    mainstreaming packages supporting options to improved sustainable low-emission
    economic recovery, development and job creation programs  safety nets and social
    protection in the transition; and broadened access to finance, technology and
    capacity-building and coordinated support to low-emission infrastructure , especially
    in developing regions, and under debt stress .'
  - 'Cities, Settlements and Infrastructure  Urban systems are critical for achieving
    deep emissions reductions and advancing climate resilient development, particularly
    when this involves integrated planning that incorporates physical, natural and
    social infrastructure . Deep emissions reductions and integrated adaptation actions
    are advanced by: integrated, inclusive land use planning and decision-making;
    compact urban form by co-locating jobs and housing; reducing or changing urban
    energy and material consumption; electrification in combination with low emissions
    sources; improved water and waste management infrastructure; and enhancing carbon
    uptake and storage in the urban environment . Cities can achieve net zero emissions
    if emissions are reduced within and outside of their administrative boundaries
    through supply chains, creating beneficial cascading effects across other sectors.  Considering
    climate change impacts and risks  in the design and planning of urban and rural
    settlements and infrastructure is critical for resilience and enhancing human
    well-being. Effective mitigation can be advanced at each of the design, construction,
    retrofit, use and disposal stages for buildings. Mitigation interventions for
    buildings include: at the construction phase, lowemission construction materials,
    highly efficient building envelope and the integration of renewable energy solutions;
    at the use phase, highly efficient appliances/equipment, the optimisation of the
    use of buildings and their supply with low-emission energy sources; and at the
    disposal phase, recycling and re-using construction materials. Sufficiency 155
    measures can limit the demand for energy and materials over the lifecycle of buildings
    and appliances.   Transport-related GHG emissions can be reduced by demand-side
    options and low-GHG emissions technologies. Changes in urban form, reallocation
    of street space for cycling and walking, digitalisation and programs that encourage
    changes in consumer behaviour can reduce demand for transport services and support
    the shift to more energy efficient transport modes. Electric vehicles powered
    by low-emissions electricity offer the largest decarbonisation potential for land-based
    transport, on a life cycle basis. Costs of electrified vehicles are decreasing
    and their adoption is accelerating, but they require continued investments in
    supporting infrastructure to increase scale of deployment. The environmental footprint
    of battery production and growing concerns about critical minerals can be addressed
    by material and supply diversification strategies, energy and material efficiency
    improvements, and circular material flows . Advances in battery technologies could
    facilitate the electrification of heavy-duty trucks and compliment conventional
    electric rail systems. Sustainable biofuels can offer additional mitigation benefits
    in land-based transport in the short and medium term. Sustainable biofuels, low-emissions
    hydrogen, and derivatives can support mitigation of CO2 emissions from shipping,
    aviation, and heavy-duty land transport but require production process improvements
    and cost reductions. Key infrastructure systems including sanitation, water, health,
    transport, communications and energy will be increasingly vulnerable if design
    standards do not account for changing climate conditions.  Green/natural and blue
    infrastructure such as urban forestry, green roofs, ponds and lakes, and river
    restoration can mitigate climate change through carbon uptake and storage, avoided
    emissions, and reduced energy use while reducing risk from extreme events such
    as heatwaves, heavy precipitation and droughts, and advancing co-benefits for
    health, well-being and livelihoods. Urban greening can provide local cooling.
    Combining green/natural and grey/physical infrastructure adaptation responses
    has potential to reduce adaptation costs and contribute to flood control, sanitation,
    water resources management, landslide prevention and coastal protection. Globally,
    more financing is directed at grey/physical infrastructure than green/natural
    infrastructure and social infrastructure, and there is limited evidence of investment
    in informal settlements . The greatest gains in well-being in urban areas can
    be achieved by prioritising finance to reduce climate risk for low-income and
    marginalised communities including people living in informal settlements.  Responses
    to ongoing sea level rise and land subsidence in low-lying coastal cities and
    settlements and small islands include protection, accommodation, advance and planned
    relocation. These responses are more effective if combined and/or sequenced, planned
    well ahead, aligned with sociocultural values and development priorities, and
    underpinned by inclusive community engagement processes. '
  - Health and Nutrition  Human health will benefit from integrated mitigation and
    adaptation options that mainstream health into food, infrastructure, social protection,
    and water policies . Balanced and sustainable healthy diets and reduced food loss
    and waste present important opportunities for adaptation and mitigation while
    generating significant co-benefits in terms of biodiversity and human health.
    Public health policies to improve nutrition, such as increasing the diversity
    of food sources in public procurement, health insurance, financial incentives,
    and awareness-raising campaigns, can potentially influence food demand, reduce
    food waste, reduce healthcare costs, contribute to lower GHG emissions and enhance
    adaptive capacity. Improved access to clean energy sources and technologies, and
    shifts to active mobility and public transport can deliver socioeconomic, air
    quality and health benefits, especially for women and children.  Effective adaptation
    options exist to help protect human health and well-being. Health Action Plans
    that include early warning and response systems are effective for extreme heat
    . Effective options for water-borne and food-borne diseases include improving
    access to potable water, reducing exposure of water and sanitation systems to
    flooding and extreme weather events, and improved early warning systems. For vector-borne
    diseases, effective adaptation options include surveillance, early warning systems,
    and vaccine development. Effective adaptation options for reducing mental health
    risks under climate change include improving surveillance and access to mental
    health care, and monitoring of psychosocial impacts from extreme weather events.
    A key pathway to climate resilience in the health sector is universal access to
    healthcare.
  - 'Co-Benefits of Adaptation and Mitigation for Sustainable Development Goals  Mitigation
    and adaptation actions have more synergies than trade-offs with Sustainable Development
    Goals . Synergies and trade-offs depend on context and scale of implementation.
    Potential trade-offs can be compensated or avoided with additional policies, investments
    and financial partnerships. Many mitigation and adaptation actions have multiple
    synergies with Sustainable Development Goals, but some actions can also have trade-offs.
    Potential synergies with SDGs exceed potential trade-offs. Synergies and trade-offs
    are context specific and depend on: means and scale of implementation, intra-
    and inter-sectoral interactions, cooperation between countries and regions, the
    sequencing, timing and stringency of actions, governance, and policy design. Eradicating
    extreme poverty, energy poverty, and providing decent living standards to all,
    consistent with nearterm sustainable development objectives, can be achieved without
    significant global emissions growth.  Several mitigation and adaptation options
    can harness nearterm synergies and reduce trade-offs to advance sustainable development
    in energy, urban and land systems . Clean energy supply systems have multiple
    co-benefits, including improvements in air quality and health. Heat Health Action
    Plans that include early warning and response systems, approaches that mainstream
    health into food, livelihoods, social protection, water and sanitation benefit
    health and wellbeing. There are potential synergies between multiple Sustainable
    Development Goals and sustainable land use and urban planning with more green
    spaces, reduced air pollution, and demand-side mitigation including shifts to
    balanced, sustainable healthy diets. Electrification combined with low-GHG energy,
    and shifts to public transport can enhance health, employment, and can contribute
    to energy security and deliver equity. Conservation, protection and restoration
    of terrestrial, freshwater, coastal and ocean ecosystems, together with targeted
    management to adapt to unavoidable impacts of climate change can generate multiple
    additional benefits, such as agricultural productivity, food security, and biodiversity
    conservation.  When implementing mitigation and adaptation together, and taking
    trade-offs into account, multiple co-benefits and synergies for human well-being
    as well as ecosystem and planetary health can be realised. There is a strong link
    between sustainable development, vulnerability and climate risks. Social safety
    nets that support climate change adaptation have strong co-benefits with development
    goals such as education, poverty alleviation, gender inclusion and food security.
    Land restoration contributes to mitigation and adaptation with synergies via enhanced
    ecosystem services and with economically positive returns and co-benefits for
    poverty reduction and improved livelihoods. Trade-offs can be evaluated and minimised
    by giving emphasis to capacity building, finance, technology transfer, investments;
    governance, development, context specific gender-based and other social equity
    considerations with meaningful participation of Indigenous Peoples, local communities
    and vulnerable populations. .  Context relevant design and implementation requires
    considering people’s needs, biodiversity, and other sustainable development dimensions.
    Countries at all stages of economic development seek to improve the well-being
    of people, and their development priorities reflect different starting points
    and contexts. Different contexts include but are not limited to social, economic,
    environmental, cultural, or political circumstances, resource endowment, capabilities,
    international environment, and prior development. n regions with high dependency
    on fossil fuels for, among other things, revenue and employment generation, mitigating
    risks for sustainable development requires policies that promote economic and
    energy sector diversification and considerations of just transitions principles,
    processes and practices. For individuals and households in low-lying coastal areas,
    in Small Islands, and smallholder farmers transitioning from incremental to transformational
    adaptation can help overcome soft adaptation limits. Effective governance is needed
    to limit trade-offs of some mitigation options such as large scale afforestation
    and bioenergy options due to risks from their deployment for food systems, biodiversity,
    other ecosystem functions and services, and livelihoods. Effective governance
    requires adequate institutional capacity at all levels .'
  - Integration of Near-Term Actions Across Sectors and Systems  The feasibility,
    effectiveness and benefits of mitigation and adaptation actions are increased
    when multi-sectoral solutions are undertaken that cut across systems. When such
    options are combined with broader sustainable development objectives, they can
    yield greater benefits for human well-being, social equity and justice, and ecosystem
    and planetary health. Climate resilient development strategies that treat climate,
    ecosystems and biodiversity, and human society as parts of an integrated system
    are the most effective. Human and ecosystem vulnerability are interdependent.
    Climate resilient development is enabled when decision-making processes and actions
    are integrated across sectors. Synergies with and progress towards the Sustainable
    Development Goals enhance prospects for climate resilient development. Choices
    and actions that treat humans and ecosystems as an integrated system build on
    diverse knowledge about climate risk, equitable, just and inclusive approaches,
    and ecosystem stewardship.  Approaches that align goals and actions across sectors
    provide opportunities for multiple and large-scale benefits and avoided damages
    in the near term. Such measures can also achieve greater benefits through cascading
    effects across sectors . For example, the feasibility of using land for both agriculture
    and centralised solar production can increase when such options are combined.
    Similarly, integrated transport and energy infrastructure planning and operations
    can together reduce the environmental, social, and economic impacts of decarbonising
    the transport and energy sectors. The implementation of packages of multiple city-scale
    mitigation strategies can have cascading effects across sectors and reduce GHG
    emissions both within and outside a city’s administrative boundaries . Integrated
    design approaches to the construction and retrofit of buildings provide increasing
    examples of zero energy or zero carbon buildings in several regions. To minimise
    maladaptation, multi-sectoral, multi-actor and inclusive planning with flexible
    pathways encourages low-regret and timely actions that keep options open, ensure
    benefits in multiple sectors and systems and suggest the available solution space
    for adapting to long-term climate change . Trade-offs in terms of employment,
    water use, land-use competition and biodiversity, as well as access to, and the
    affordability of, energy, food, and water can be avoided by well-implemented land-based
    mitigation options, especially those that do not threaten existing sustainable
    land uses and land rights, with frameworks for integrated policy implementation.  Mitigation
    and adaptation when implemented together, and combined with broader sustainable
    development objectives, would yield multiple benefits for human well-being as
    well as ecosystem and planetary health. The range of such positive interactions
    is significant in the landscape of near-term climate policies across regions,
    sectors and systems. For example, AFOLU mitigation actions in land-use change
    and forestry, when sustainably implemented, can provide large-scale GHG emission
    reductions and removals that simultaneously benefit biodiversity, food security,
    wood supply and other ecosystem services but cannot fully compensate for delayed
    mitigation action in other sectors. Adaptation measures in land, ocean and ecosystems
    similarly can have widespread benefits for food security, nutrition, health and
    well-being, ecosystems and biodiversity. Equally, urban systems are critical,
    interconnected sites for climate resilient development; urban policies that implement
    multiple interventions can yield adaptation or mitigation gains with equity and
    human well-being. Integrated policy packages can improve the ability to integrate
    considerations of equity, gender equality and justice. Coordinated cross-sectoral
    policies and planning can maximise synergies and avoid or reduce trade-offs between
    mitigation and adaptation. Effective action in all of the above areas will require
    near-term political commitment and follow-through, social cooperation, finance,
    and more integrated cross-sectoral policies and support and actions. .
  C.5.1:
  - Equity and Inclusion in Climate Change Action  Actions that prioritise equity,
    climate justice, social justice and inclusion lead to more sustainable outcomes,
    co-benefits, reduce trade-offs, support transformative change and advance climate
    resilient development. Adaptation responses are immediately needed to reduce rising
    climate risks, especially for the most vulnerable. Equity, inclusion and just
    transitions are key to progress on adaptation and deeper societal ambitions for
    accelerated mitigation. Adaptation and mitigation actions, across scales, sectors
    and regions, that prioritise equity, climate justice, rights-based approaches,
    social justice and inclusivity, lead to more sustainable outcomes, reduce trade-offs,
    support transformative change and advance climate resilient development . Redistributive
    policies across sectors and regions that shield the poor and vulnerable, social
    safety nets, equity, inclusion and just transitions, at all scales can enable
    deeper societal ambitions and resolve trade-offs with sustainable development
    goals., particularly education, hunger, poverty, gender and energy access . Mitigation
    efforts embedded within the wider development context can increase the pace, depth
    and breadth of emission reductions . Equity, inclusion and just transitions at
    all scales enable deeper societal ambitions for accelerated mitigation, and climate
    action more broadly. The complexity in risk of rising food prices, reduced household
    incomes, and health and climate-related malnutrition  and mortality increases
    with little or low levels of adaptation.  Regions and people with considerable
    development constraints have high vulnerability to climatic hazards. Adaptation
    outcomes for the most vulnerable within and across countries and regions are enhanced
    through approaches focusing on equity, inclusivity, and rights-based approaches,
    including 3.3 to 3.6 billion people living in contexts that are highly vulnerable
    to climate change. Vulnerability is higher in locations with poverty, governance
    challenges and limited access to basic services and resources, violent conflict
    and high levels of climate-sensitive livelihoods  . Several risks can be moderated
    with adaptation. The largest adaptation gaps exist among lower income population
    groups and adaptation progress is unevenly distributed with observed adaptation
    gaps. Present development challenges causing high vulnerability are influenced
    by historical and ongoing patterns of inequity such as colonialism, especially
    for many Indigenous Peoples and local communities. Vulnerability is exacerbated
    by inequity and marginalisation linked to gender, ethnicity, low income or combinations
    thereof, especially for many Indigenous Peoples and local communities.  Meaningful
    participation and inclusive planning, informed by cultural values, Indigenous
    Knowledge, local knowledge, and scientific knowledge can help address adaptation
    gaps and avoid maladaptation. Such actions with flexible pathways may encourage
    low-regret and timely actions . Integrating climate adaptation into social protection
    programmes, including cash transfers and public works programmes, would increase
    resilience to climate change, especially when supported by basic services and
    infrastructure.  Equity, inclusion, just transitions, broad and meaningful participation
    of all relevant actors in decision making at all scales enable deeper societal
    ambitions for accelerated mitigation, and climate action more broadly, and build
    social trust, support transformative changes and an equitable sharing of benefits
    and burdens. Equity remains a central element in the UN climate regime, notwithstanding
    shifts in differentiation between states over time and challenges in assessing
    fair shares. Ambitious mitigation pathways imply large and sometimes disruptive
    changes in economic structure, with significant distributional consequences, within
    and between countries, including shifting of income and employment during the
    transition from high to low emissions activities. While some jobs may be lost,
    low-emissions development can also open up opportunities to enhance skills and
    create jobs. Broadening equitable access to finance, technologies and governance
    that facilitate mitigation, and consideration of climate justice can help equitable
    sharing of benefits and burdens, especially for vulnerable countries and communities.  Development
    priorities among countries also reflect different starting points and contexts,
    and enabling conditions for shifting development pathways towards increased sustainability
    will therefore differ, giving rise to different needs . Implementing just transition
    principles through collective and participatory decision-making processes is an
    effective way of integrating equity principles into policies at all scales depending
    on national circumstances, while in several countries just transition commissions,
    task forces and national policies have been established .  Many economic and regulatory
    instruments have been effective in reducing emissions and practical experience
    has informed instrument design to improve them while addressing distributional
    goals and social acceptance. The design of behavioural interventions, including
    the way that choices are presented to consumers work synergistically with price
    signals, making the combination more effective. Individuals with high socio-economic
    status contribute disproportionately to emissions, and have the highest potential
    for emissions reductions, e.g., as citizens, investors, consumers, role models,
    and professionals . There are options on design of instruments such as taxes,
    subsidies, prices, and consumption-based approaches, complemented by regulatory
    instruments to reduce high-emissions consumption while improving equity and societal
    well-being. Behaviour and lifestyle changes to help end-users adopt low-GHG-intensive
    options can be supported by policies, infrastructure and technology with multiple
    co-benefits for societal well-being. Broadening equitable access to domestic and
    international finance, technologies and capacity can also act as a catalyst for
    accelerating mitigation and shifting development pathways in low-income contexts
    . Eradicating extreme poverty, energy poverty, and providing decent living standards
    to all in these regions in the context of achieving sustainable development objectives,
    in the near term, can be achieved without significant global emissions growth.
    Technology development, transfer, capacity building and financing can support
    developing countries/ regions leapfrogging or transitioning to low-emissions transport
    systems thereby providing multiple co-benefits . Climate resilient development
    is advanced when actors work in equitable, just and enabling ways to reconcile
    divergent interests, values and worldviews, toward equitable and just outcomes
    .
  C.5.2:
  - Equity and Inclusion in Climate Change Action  Actions that prioritise equity,
    climate justice, social justice and inclusion lead to more sustainable outcomes,
    co-benefits, reduce trade-offs, support transformative change and advance climate
    resilient development. Adaptation responses are immediately needed to reduce rising
    climate risks, especially for the most vulnerable. Equity, inclusion and just
    transitions are key to progress on adaptation and deeper societal ambitions for
    accelerated mitigation. Adaptation and mitigation actions, across scales, sectors
    and regions, that prioritise equity, climate justice, rights-based approaches,
    social justice and inclusivity, lead to more sustainable outcomes, reduce trade-offs,
    support transformative change and advance climate resilient development . Redistributive
    policies across sectors and regions that shield the poor and vulnerable, social
    safety nets, equity, inclusion and just transitions, at all scales can enable
    deeper societal ambitions and resolve trade-offs with sustainable development
    goals., particularly education, hunger, poverty, gender and energy access . Mitigation
    efforts embedded within the wider development context can increase the pace, depth
    and breadth of emission reductions . Equity, inclusion and just transitions at
    all scales enable deeper societal ambitions for accelerated mitigation, and climate
    action more broadly. The complexity in risk of rising food prices, reduced household
    incomes, and health and climate-related malnutrition  and mortality increases
    with little or low levels of adaptation.  Regions and people with considerable
    development constraints have high vulnerability to climatic hazards. Adaptation
    outcomes for the most vulnerable within and across countries and regions are enhanced
    through approaches focusing on equity, inclusivity, and rights-based approaches,
    including 3.3 to 3.6 billion people living in contexts that are highly vulnerable
    to climate change. Vulnerability is higher in locations with poverty, governance
    challenges and limited access to basic services and resources, violent conflict
    and high levels of climate-sensitive livelihoods  . Several risks can be moderated
    with adaptation. The largest adaptation gaps exist among lower income population
    groups and adaptation progress is unevenly distributed with observed adaptation
    gaps. Present development challenges causing high vulnerability are influenced
    by historical and ongoing patterns of inequity such as colonialism, especially
    for many Indigenous Peoples and local communities. Vulnerability is exacerbated
    by inequity and marginalisation linked to gender, ethnicity, low income or combinations
    thereof, especially for many Indigenous Peoples and local communities.  Meaningful
    participation and inclusive planning, informed by cultural values, Indigenous
    Knowledge, local knowledge, and scientific knowledge can help address adaptation
    gaps and avoid maladaptation. Such actions with flexible pathways may encourage
    low-regret and timely actions . Integrating climate adaptation into social protection
    programmes, including cash transfers and public works programmes, would increase
    resilience to climate change, especially when supported by basic services and
    infrastructure.  Equity, inclusion, just transitions, broad and meaningful participation
    of all relevant actors in decision making at all scales enable deeper societal
    ambitions for accelerated mitigation, and climate action more broadly, and build
    social trust, support transformative changes and an equitable sharing of benefits
    and burdens. Equity remains a central element in the UN climate regime, notwithstanding
    shifts in differentiation between states over time and challenges in assessing
    fair shares. Ambitious mitigation pathways imply large and sometimes disruptive
    changes in economic structure, with significant distributional consequences, within
    and between countries, including shifting of income and employment during the
    transition from high to low emissions activities. While some jobs may be lost,
    low-emissions development can also open up opportunities to enhance skills and
    create jobs. Broadening equitable access to finance, technologies and governance
    that facilitate mitigation, and consideration of climate justice can help equitable
    sharing of benefits and burdens, especially for vulnerable countries and communities.  Development
    priorities among countries also reflect different starting points and contexts,
    and enabling conditions for shifting development pathways towards increased sustainability
    will therefore differ, giving rise to different needs . Implementing just transition
    principles through collective and participatory decision-making processes is an
    effective way of integrating equity principles into policies at all scales depending
    on national circumstances, while in several countries just transition commissions,
    task forces and national policies have been established .  Many economic and regulatory
    instruments have been effective in reducing emissions and practical experience
    has informed instrument design to improve them while addressing distributional
    goals and social acceptance. The design of behavioural interventions, including
    the way that choices are presented to consumers work synergistically with price
    signals, making the combination more effective. Individuals with high socio-economic
    status contribute disproportionately to emissions, and have the highest potential
    for emissions reductions, e.g., as citizens, investors, consumers, role models,
    and professionals . There are options on design of instruments such as taxes,
    subsidies, prices, and consumption-based approaches, complemented by regulatory
    instruments to reduce high-emissions consumption while improving equity and societal
    well-being. Behaviour and lifestyle changes to help end-users adopt low-GHG-intensive
    options can be supported by policies, infrastructure and technology with multiple
    co-benefits for societal well-being. Broadening equitable access to domestic and
    international finance, technologies and capacity can also act as a catalyst for
    accelerating mitigation and shifting development pathways in low-income contexts
    . Eradicating extreme poverty, energy poverty, and providing decent living standards
    to all in these regions in the context of achieving sustainable development objectives,
    in the near term, can be achieved without significant global emissions growth.
    Technology development, transfer, capacity building and financing can support
    developing countries/ regions leapfrogging or transitioning to low-emissions transport
    systems thereby providing multiple co-benefits . Climate resilient development
    is advanced when actors work in equitable, just and enabling ways to reconcile
    divergent interests, values and worldviews, toward equitable and just outcomes
    .
  C.5.3:
  - Equity and Inclusion in Climate Change Action  Actions that prioritise equity,
    climate justice, social justice and inclusion lead to more sustainable outcomes,
    co-benefits, reduce trade-offs, support transformative change and advance climate
    resilient development. Adaptation responses are immediately needed to reduce rising
    climate risks, especially for the most vulnerable. Equity, inclusion and just
    transitions are key to progress on adaptation and deeper societal ambitions for
    accelerated mitigation. Adaptation and mitigation actions, across scales, sectors
    and regions, that prioritise equity, climate justice, rights-based approaches,
    social justice and inclusivity, lead to more sustainable outcomes, reduce trade-offs,
    support transformative change and advance climate resilient development . Redistributive
    policies across sectors and regions that shield the poor and vulnerable, social
    safety nets, equity, inclusion and just transitions, at all scales can enable
    deeper societal ambitions and resolve trade-offs with sustainable development
    goals., particularly education, hunger, poverty, gender and energy access . Mitigation
    efforts embedded within the wider development context can increase the pace, depth
    and breadth of emission reductions . Equity, inclusion and just transitions at
    all scales enable deeper societal ambitions for accelerated mitigation, and climate
    action more broadly. The complexity in risk of rising food prices, reduced household
    incomes, and health and climate-related malnutrition  and mortality increases
    with little or low levels of adaptation.  Regions and people with considerable
    development constraints have high vulnerability to climatic hazards. Adaptation
    outcomes for the most vulnerable within and across countries and regions are enhanced
    through approaches focusing on equity, inclusivity, and rights-based approaches,
    including 3.3 to 3.6 billion people living in contexts that are highly vulnerable
    to climate change. Vulnerability is higher in locations with poverty, governance
    challenges and limited access to basic services and resources, violent conflict
    and high levels of climate-sensitive livelihoods  . Several risks can be moderated
    with adaptation. The largest adaptation gaps exist among lower income population
    groups and adaptation progress is unevenly distributed with observed adaptation
    gaps. Present development challenges causing high vulnerability are influenced
    by historical and ongoing patterns of inequity such as colonialism, especially
    for many Indigenous Peoples and local communities. Vulnerability is exacerbated
    by inequity and marginalisation linked to gender, ethnicity, low income or combinations
    thereof, especially for many Indigenous Peoples and local communities.  Meaningful
    participation and inclusive planning, informed by cultural values, Indigenous
    Knowledge, local knowledge, and scientific knowledge can help address adaptation
    gaps and avoid maladaptation. Such actions with flexible pathways may encourage
    low-regret and timely actions . Integrating climate adaptation into social protection
    programmes, including cash transfers and public works programmes, would increase
    resilience to climate change, especially when supported by basic services and
    infrastructure.  Equity, inclusion, just transitions, broad and meaningful participation
    of all relevant actors in decision making at all scales enable deeper societal
    ambitions for accelerated mitigation, and climate action more broadly, and build
    social trust, support transformative changes and an equitable sharing of benefits
    and burdens. Equity remains a central element in the UN climate regime, notwithstanding
    shifts in differentiation between states over time and challenges in assessing
    fair shares. Ambitious mitigation pathways imply large and sometimes disruptive
    changes in economic structure, with significant distributional consequences, within
    and between countries, including shifting of income and employment during the
    transition from high to low emissions activities. While some jobs may be lost,
    low-emissions development can also open up opportunities to enhance skills and
    create jobs. Broadening equitable access to finance, technologies and governance
    that facilitate mitigation, and consideration of climate justice can help equitable
    sharing of benefits and burdens, especially for vulnerable countries and communities.  Development
    priorities among countries also reflect different starting points and contexts,
    and enabling conditions for shifting development pathways towards increased sustainability
    will therefore differ, giving rise to different needs . Implementing just transition
    principles through collective and participatory decision-making processes is an
    effective way of integrating equity principles into policies at all scales depending
    on national circumstances, while in several countries just transition commissions,
    task forces and national policies have been established .  Many economic and regulatory
    instruments have been effective in reducing emissions and practical experience
    has informed instrument design to improve them while addressing distributional
    goals and social acceptance. The design of behavioural interventions, including
    the way that choices are presented to consumers work synergistically with price
    signals, making the combination more effective. Individuals with high socio-economic
    status contribute disproportionately to emissions, and have the highest potential
    for emissions reductions, e.g., as citizens, investors, consumers, role models,
    and professionals . There are options on design of instruments such as taxes,
    subsidies, prices, and consumption-based approaches, complemented by regulatory
    instruments to reduce high-emissions consumption while improving equity and societal
    well-being. Behaviour and lifestyle changes to help end-users adopt low-GHG-intensive
    options can be supported by policies, infrastructure and technology with multiple
    co-benefits for societal well-being. Broadening equitable access to domestic and
    international finance, technologies and capacity can also act as a catalyst for
    accelerating mitigation and shifting development pathways in low-income contexts
    . Eradicating extreme poverty, energy poverty, and providing decent living standards
    to all in these regions in the context of achieving sustainable development objectives,
    in the near term, can be achieved without significant global emissions growth.
    Technology development, transfer, capacity building and financing can support
    developing countries/ regions leapfrogging or transitioning to low-emissions transport
    systems thereby providing multiple co-benefits . Climate resilient development
    is advanced when actors work in equitable, just and enabling ways to reconcile
    divergent interests, values and worldviews, toward equitable and just outcomes
    .
  - 'Cities, Settlements and Infrastructure  Urban systems are critical for achieving
    deep emissions reductions and advancing climate resilient development, particularly
    when this involves integrated planning that incorporates physical, natural and
    social infrastructure . Deep emissions reductions and integrated adaptation actions
    are advanced by: integrated, inclusive land use planning and decision-making;
    compact urban form by co-locating jobs and housing; reducing or changing urban
    energy and material consumption; electrification in combination with low emissions
    sources; improved water and waste management infrastructure; and enhancing carbon
    uptake and storage in the urban environment . Cities can achieve net zero emissions
    if emissions are reduced within and outside of their administrative boundaries
    through supply chains, creating beneficial cascading effects across other sectors.  Considering
    climate change impacts and risks  in the design and planning of urban and rural
    settlements and infrastructure is critical for resilience and enhancing human
    well-being. Effective mitigation can be advanced at each of the design, construction,
    retrofit, use and disposal stages for buildings. Mitigation interventions for
    buildings include: at the construction phase, lowemission construction materials,
    highly efficient building envelope and the integration of renewable energy solutions;
    at the use phase, highly efficient appliances/equipment, the optimisation of the
    use of buildings and their supply with low-emission energy sources; and at the
    disposal phase, recycling and re-using construction materials. Sufficiency 155
    measures can limit the demand for energy and materials over the lifecycle of buildings
    and appliances.   Transport-related GHG emissions can be reduced by demand-side
    options and low-GHG emissions technologies. Changes in urban form, reallocation
    of street space for cycling and walking, digitalisation and programs that encourage
    changes in consumer behaviour can reduce demand for transport services and support
    the shift to more energy efficient transport modes. Electric vehicles powered
    by low-emissions electricity offer the largest decarbonisation potential for land-based
    transport, on a life cycle basis. Costs of electrified vehicles are decreasing
    and their adoption is accelerating, but they require continued investments in
    supporting infrastructure to increase scale of deployment. The environmental footprint
    of battery production and growing concerns about critical minerals can be addressed
    by material and supply diversification strategies, energy and material efficiency
    improvements, and circular material flows . Advances in battery technologies could
    facilitate the electrification of heavy-duty trucks and compliment conventional
    electric rail systems. Sustainable biofuels can offer additional mitigation benefits
    in land-based transport in the short and medium term. Sustainable biofuels, low-emissions
    hydrogen, and derivatives can support mitigation of CO2 emissions from shipping,
    aviation, and heavy-duty land transport but require production process improvements
    and cost reductions. Key infrastructure systems including sanitation, water, health,
    transport, communications and energy will be increasingly vulnerable if design
    standards do not account for changing climate conditions.  Green/natural and blue
    infrastructure such as urban forestry, green roofs, ponds and lakes, and river
    restoration can mitigate climate change through carbon uptake and storage, avoided
    emissions, and reduced energy use while reducing risk from extreme events such
    as heatwaves, heavy precipitation and droughts, and advancing co-benefits for
    health, well-being and livelihoods. Urban greening can provide local cooling.
    Combining green/natural and grey/physical infrastructure adaptation responses
    has potential to reduce adaptation costs and contribute to flood control, sanitation,
    water resources management, landslide prevention and coastal protection. Globally,
    more financing is directed at grey/physical infrastructure than green/natural
    infrastructure and social infrastructure, and there is limited evidence of investment
    in informal settlements . The greatest gains in well-being in urban areas can
    be achieved by prioritising finance to reduce climate risk for low-income and
    marginalised communities including people living in informal settlements.  Responses
    to ongoing sea level rise and land subsidence in low-lying coastal cities and
    settlements and small islands include protection, accommodation, advance and planned
    relocation. These responses are more effective if combined and/or sequenced, planned
    well ahead, aligned with sociocultural values and development priorities, and
    underpinned by inclusive community engagement processes. '
  - Health and Nutrition  Human health will benefit from integrated mitigation and
    adaptation options that mainstream health into food, infrastructure, social protection,
    and water policies . Balanced and sustainable healthy diets and reduced food loss
    and waste present important opportunities for adaptation and mitigation while
    generating significant co-benefits in terms of biodiversity and human health.
    Public health policies to improve nutrition, such as increasing the diversity
    of food sources in public procurement, health insurance, financial incentives,
    and awareness-raising campaigns, can potentially influence food demand, reduce
    food waste, reduce healthcare costs, contribute to lower GHG emissions and enhance
    adaptive capacity. Improved access to clean energy sources and technologies, and
    shifts to active mobility and public transport can deliver socioeconomic, air
    quality and health benefits, especially for women and children.  Effective adaptation
    options exist to help protect human health and well-being. Health Action Plans
    that include early warning and response systems are effective for extreme heat
    . Effective options for water-borne and food-borne diseases include improving
    access to potable water, reducing exposure of water and sanitation systems to
    flooding and extreme weather events, and improved early warning systems. For vector-borne
    diseases, effective adaptation options include surveillance, early warning systems,
    and vaccine development. Effective adaptation options for reducing mental health
    risks under climate change include improving surveillance and access to mental
    health care, and monitoring of psychosocial impacts from extreme weather events.
    A key pathway to climate resilience in the health sector is universal access to
    healthcare.
  - Society, Livelihoods, and Economies  Enhancing knowledge on risks and available
    adaptation options promotes societal responses, and behaviour and lifestyle changes
    supported by policies, infrastructure and technology can help reduce global GHG
    emissions. Climate literacy and information provided through climate services
    and community approaches, including those that are informed by Indigenous Knowledge
    and local knowledge, can accelerate behavioural changes and planning . Educational
    and information programmes, using the arts, participatory modelling and citizen
    science can facilitate awareness, heighten risk perception, and influence behaviours
    . The way choices are presented can enable adoption of low GHG intensive socio-cultural
    options, such as shifts to balanced, sustainable healthy diets, reduced food waste,
    and active mobility. Judicious labelling, framing, and communication of social
    norms can increase the effect of mandates, subsidies, or taxes.  A range of adaptation
    options, such as disaster risk management, early warning systems, climate services
    and risk spreading and sharing approaches, have broad applicability across sectors
    and provide greater risk reduction benefits when combined . Climate services that
    are demand-driven and inclusive of different users and providers can improve agricultural
    practices, inform better water use and efficiency, and enable resilient infrastructure
    planning. Policy mixes that include weather and health insurance, social protection
    and adaptive safety nets, contingent finance and reserve funds, and universal
    access to early warning systems combined with effective contingency plans, can
    reduce vulnerability and exposure of human systems. Integrating climate adaptation
    into social protection programs, including cash transfers and public works programs,
    is highly feasible and increases resilience to climate change, especially when
    supported by basic services and infrastructure. Social safety nets can build adaptive
    capacities, reduce socioeconomic vulnerability, and reduce risk linked to hazards.  Reducing
    future risks of involuntary migration and displacement due to climate change is
    possible through cooperative, international efforts to enhance institutional adaptive
    capacity and sustainable development. Increasing adaptive capacity minimises risk
    associated with involuntary migration and immobility and improves the degree of
    choice under which migration decisions are made, while policy interventions can
    remove barriers and expand the alternatives for safe, orderly and regular migration
    that allows vulnerable people to adapt to climate change.  Accelerating commitment
    and follow-through by the private sector is promoted for instance by building
    business cases for adaptation, accountability and transparency mechanisms, and
    monitoring and evaluation of adaptation progress . Integrated pathways for managing
    climate risks will be most suitable when so-called ‘low-regret’ anticipatory options
    are established jointly across sectors in a timely manner and are feasible and
    effective in their local context, and when path dependencies and maladaptations
    across sectors are avoided. Sustained adaptation actions are strengthened by mainstreaming
    adaptation into institutional budget and policy planning cycles, statutory planning,
    monitoring and evaluation frameworks and into recovery efforts from disaster events.
    Instruments that incorporate adaptation such as policy and legal frameworks, behavioural
    incentives, and economic instruments that address market failures, such as climate
    risk disclosure, inclusive and deliberative processes strengthen adaptation actions
    by public and private actors.
  C.5.4:
  - Observed Changes, Impacts and Attribution  Human activities, principally through
    emissions of greenhouse gases, have unequivocally caused global warming, with
    global surface temperature reaching 1.1°C above 1850–1900 in 2011–2020. Global
    greenhouse gas emissions have continued to increase over 2010–2019, with unequal
    historical and ongoing contributions arising from unsustainable energy use, land
    use and land-use change, lifestyles and patterns of consumption and production
    across regions, between and within countries, and between individuals. Human-caused
    climate change is already affecting many weather and climate extremes in every
    region across the globe. This has led to widespread adverse impacts on food and
    water security, human health and on economies and society and related losses and
    damages to nature and people. Vulnerable communities who have historically contributed
    the least to current climate change are disproportionately affected.
  - Equity and Inclusion in Climate Change Action  Actions that prioritise equity,
    climate justice, social justice and inclusion lead to more sustainable outcomes,
    co-benefits, reduce trade-offs, support transformative change and advance climate
    resilient development. Adaptation responses are immediately needed to reduce rising
    climate risks, especially for the most vulnerable. Equity, inclusion and just
    transitions are key to progress on adaptation and deeper societal ambitions for
    accelerated mitigation. Adaptation and mitigation actions, across scales, sectors
    and regions, that prioritise equity, climate justice, rights-based approaches,
    social justice and inclusivity, lead to more sustainable outcomes, reduce trade-offs,
    support transformative change and advance climate resilient development . Redistributive
    policies across sectors and regions that shield the poor and vulnerable, social
    safety nets, equity, inclusion and just transitions, at all scales can enable
    deeper societal ambitions and resolve trade-offs with sustainable development
    goals., particularly education, hunger, poverty, gender and energy access . Mitigation
    efforts embedded within the wider development context can increase the pace, depth
    and breadth of emission reductions . Equity, inclusion and just transitions at
    all scales enable deeper societal ambitions for accelerated mitigation, and climate
    action more broadly. The complexity in risk of rising food prices, reduced household
    incomes, and health and climate-related malnutrition  and mortality increases
    with little or low levels of adaptation.  Regions and people with considerable
    development constraints have high vulnerability to climatic hazards. Adaptation
    outcomes for the most vulnerable within and across countries and regions are enhanced
    through approaches focusing on equity, inclusivity, and rights-based approaches,
    including 3.3 to 3.6 billion people living in contexts that are highly vulnerable
    to climate change. Vulnerability is higher in locations with poverty, governance
    challenges and limited access to basic services and resources, violent conflict
    and high levels of climate-sensitive livelihoods  . Several risks can be moderated
    with adaptation. The largest adaptation gaps exist among lower income population
    groups and adaptation progress is unevenly distributed with observed adaptation
    gaps. Present development challenges causing high vulnerability are influenced
    by historical and ongoing patterns of inequity such as colonialism, especially
    for many Indigenous Peoples and local communities. Vulnerability is exacerbated
    by inequity and marginalisation linked to gender, ethnicity, low income or combinations
    thereof, especially for many Indigenous Peoples and local communities.  Meaningful
    participation and inclusive planning, informed by cultural values, Indigenous
    Knowledge, local knowledge, and scientific knowledge can help address adaptation
    gaps and avoid maladaptation. Such actions with flexible pathways may encourage
    low-regret and timely actions . Integrating climate adaptation into social protection
    programmes, including cash transfers and public works programmes, would increase
    resilience to climate change, especially when supported by basic services and
    infrastructure.  Equity, inclusion, just transitions, broad and meaningful participation
    of all relevant actors in decision making at all scales enable deeper societal
    ambitions for accelerated mitigation, and climate action more broadly, and build
    social trust, support transformative changes and an equitable sharing of benefits
    and burdens. Equity remains a central element in the UN climate regime, notwithstanding
    shifts in differentiation between states over time and challenges in assessing
    fair shares. Ambitious mitigation pathways imply large and sometimes disruptive
    changes in economic structure, with significant distributional consequences, within
    and between countries, including shifting of income and employment during the
    transition from high to low emissions activities. While some jobs may be lost,
    low-emissions development can also open up opportunities to enhance skills and
    create jobs. Broadening equitable access to finance, technologies and governance
    that facilitate mitigation, and consideration of climate justice can help equitable
    sharing of benefits and burdens, especially for vulnerable countries and communities.  Development
    priorities among countries also reflect different starting points and contexts,
    and enabling conditions for shifting development pathways towards increased sustainability
    will therefore differ, giving rise to different needs . Implementing just transition
    principles through collective and participatory decision-making processes is an
    effective way of integrating equity principles into policies at all scales depending
    on national circumstances, while in several countries just transition commissions,
    task forces and national policies have been established .  Many economic and regulatory
    instruments have been effective in reducing emissions and practical experience
    has informed instrument design to improve them while addressing distributional
    goals and social acceptance. The design of behavioural interventions, including
    the way that choices are presented to consumers work synergistically with price
    signals, making the combination more effective. Individuals with high socio-economic
    status contribute disproportionately to emissions, and have the highest potential
    for emissions reductions, e.g., as citizens, investors, consumers, role models,
    and professionals . There are options on design of instruments such as taxes,
    subsidies, prices, and consumption-based approaches, complemented by regulatory
    instruments to reduce high-emissions consumption while improving equity and societal
    well-being. Behaviour and lifestyle changes to help end-users adopt low-GHG-intensive
    options can be supported by policies, infrastructure and technology with multiple
    co-benefits for societal well-being. Broadening equitable access to domestic and
    international finance, technologies and capacity can also act as a catalyst for
    accelerating mitigation and shifting development pathways in low-income contexts
    . Eradicating extreme poverty, energy poverty, and providing decent living standards
    to all in these regions in the context of achieving sustainable development objectives,
    in the near term, can be achieved without significant global emissions growth.
    Technology development, transfer, capacity building and financing can support
    developing countries/ regions leapfrogging or transitioning to low-emissions transport
    systems thereby providing multiple co-benefits . Climate resilient development
    is advanced when actors work in equitable, just and enabling ways to reconcile
    divergent interests, values and worldviews, toward equitable and just outcomes
    .
  C.6.1:
  - Mitigation Actions to Date  There has been a consistent expansion of policies
    and laws addressing mitigation since AR5. Climate governance supports mitigation
    by providing frameworks through which diverse actors interact, and a basis for
    policy development and implementation. Many regulatory and economic instruments
    have already been deployed successfully. By 2020, laws primarily focussed on reducing
    GHG emissions existed in 56 countries covering 53% of global emissions. The application
    of diverse policy instruments for mitigation at the national and sub-national
    levels has grown consistently across a range of sectors. Policy coverage is uneven
    across sectors and remains limited for emissions from agriculture, and from industrial
    materials and feedstocks.  Practical experience has informed economic instrument
    design and helped to improve predictability, environmental effectiveness, economic
    efficiency, alignment with distributional goals, and social acceptance. Low-emission
    technological innovation is strengthened through the combination of technology-push
    policies, together with policies that create incentives for behaviour change and
    market opportunities. Comprehensive and consistent policy packages have been found
    to be more effective than single policies. Combining mitigation with policies
    to shift development pathways, policies that induce lifestyle or behaviour changes,
    for example, measures promoting walkable urban areas combined with electrification
    and renewable energy can create health co-benefits from cleaner air and enhanced
    active mobility . Climate governance enables mitigation by providing an overall
    direction, setting targets, mainstreaming climate action across policy domains
    and levels, based on national circumstances and in the context of international
    cooperation. Effective governance enhances regulatory certainty, creating specialised
    organisations and creating the context to mobilise finance. These functions can
    be promoted by climate-relevant laws, which are growing in number, or climate
    strategies, among others, based on national and sub-national context. Effective
    and equitable climate governance builds on engagement with civil society actors,
    political actors, businesses, youth, labour, media, Indigenous Peoples and local
    communities.  The unit costs of several low-emission technologies, including solar,
    wind and lithium-ion batteries, have fallen consistently since 2010. Design and
    process innovations in combination with the use of digital technologies have led
    to near-commercial availability of many low or zero emissions options in buildings,
    transport and industry. From 2010-2019, there have been sustained decreases in
    the unit costs of solar energy , wind energy, and lithium-ion batteries, and large
    increases in their deployment, e.g., >10× for solar and >100× for electric vehicles,
    albeit varying widely across regions. Electricity from PV and wind is now cheaper
    than electricity from fossil sources in many regions, electric vehicles are increasingly
    competitive with internal combustion engines, and large-scale battery storage
    on electricity grids is increasingly viable. In comparison to modular small-unit
    size technologies, the empirical record shows that multiple large-scale mitigation
    technologies, with fewer opportunities for learning, have seen minimal cost reductions
    and their adoption has grown slowly. Maintaining emission-intensive systems may,
    in some regions and sectors, be more expensive than transitioning to low emission
    systems.  For almost all basic materials – primary metals, building materials
    and chemicals – many low- to zero-GHG intensity production processes are at the
    pilot to near-commercial and in some cases commercial stage but they are not yet
    established industrial practice. Integrated design in construction and retrofit
    of buildings has led to increasing examples of zero energy or zero carbon buildings.
    Technological innovation made possible the widespread adoption of LED lighting.
    Digital technologies including sensors, the internet of things, robotics, and
    artificial intelligence can improve energy management in all sectors; they can
    increase energy efficiency, and promote the adoption of many low-emission technologies,
    including decentralised renewable energy, while creating economic opportunities.
    However, some of these climate change mitigation gains can be reduced or counterbalanced
    by growth in demand for goods and services due to the use of digital devices.
    Several mitigation options, notably solar energy, wind energy, electrification
    of urban systems, urban green infrastructure, energy efficiency, demand side management,
    improved forest- and crop/grassland management, and reduced food waste and loss,
    are technically viable, are becoming increasingly cost effective and are generally
    supported by the public, and this enables expanded deployment in many regions.  The
    magnitude of global climate finance flows has increased and financing channels
    have broadened. Annual tracked total financial flows for climate mitigation and
    adaptation increased by up to 60% between 2013/14 and 2019/20, but average growth
    has slowed since 2018 and most climate finance stays within national borders.
    Markets for green bonds, environmental, social and governance and sustainable
    finance products have expanded significantly since AR5 . Investors, central banks,
    and financial regulators are driving increased awareness of climate risk to support
    climate policy development and implementation. Accelerated international financial
    cooperation is a critical enabler of low-GHG and just transitions.  Economic instruments
    have been effective in reducing emissions, complemented by regulatory instruments
    mainly at the national and also sub-national and regional level. By 2020, over
    20% of global GHG emissions were covered by carbon taxes or emissions trading
    systems, although coverage and prices have been insufficient to achieve deep reductions.
    Equity and distributional impacts of carbon pricing instruments can be addressed
    by using revenue from carbon taxes or emissions trading to support low-income
    households, among other approaches. The mix of policy instruments which reduced
    costs and stimulated adoption of solar energy, wind energy and lithium-ion batteries
    includes public R&D, funding for demonstration and pilot projects, and demand-pull
    instruments such as deployment subsidies to attain scale .  Mitigation actions,
    supported by policies, have contributed to a decrease in global energy and carbon
    intensity between 2010 and 2019, with a growing number of countries achieving
    absolute GHG emission reductions for more than a decade . While global net GHG
    emissions have increased since 2010, global energy intensity decreased by 2% yr
    –1 between 2010 and 2019. Global carbon intensity also decreased by 0.3% yr –1
    , mainly due to fuel switching from coal to gas, reduced expansion of coal capacity,
    and increased use of renewables, and with large regional variations over the same
    period. In many countries, policies have enhanced energy efficiency, reduced rates
    of deforestation and accelerated technology deployment, leading to avoided and
    in some cases reduced or removed emissions. At least 18 countries have sustained
    production-based CO2 and GHG and consumption-based CO2 absolute emission reductions
    for longer than 10 years since 2005 through energy supply decarbonization, energy
    efficiency gains, and energy demand reduction, which resulted from both policies
    and changes in economic structure. Some countries have reduced production-based
    GHG emissions by a third or more since peaking, and some have achieved reduction
    rates of around 4% yr–1 for several years consecutively. Multiple lines of evidence
    suggest that mitigation policies have led to avoided global emissions of several
    GtCO 2-eq yr–1. At least 1.8 GtCO2-eq yr–1 of avoided emissions can be accounted
    for by aggregating separate estimates for the effects of economic and regulatory
    instruments. Growing numbers of laws and executive orders have impacted global
    emissions and are estimated to have resulted in 5.9 GtCO2 -eq yr–1 of avoided
    emissions in 2016. These reductions have only partly offset global emissions growth.
  - Governance and Policy for Near-Term Climate Change Action  Effective climate action
    requires political commitment, well-aligned multi-level governance and institutional
    frameworks, laws, policies and strategies. It needs clear goals, adequate finance
    and financing tools, coordination across multiple policy domains, and inclusive
    governance processes. Many mitigation and adaptation policy instruments have been
    deployed successfully, and could support deep emissions reductions and climate
    resilience if scaled up and applied widely, depending on national circumstances.
    Adaptation and mitigation action benefits from drawing on diverse knowledge. Effective
    climate governance enables mitigation and adaptation by providing overall direction
    based on national circumstances, setting targets and priorities, mainstreaming
    climate action across policy domains and levels, based on national circumstances
    and in the context of international cooperation. Effective governance enhances
    monitoring and evaluation and regulatory certainty, prioritising inclusive, transparent
    and equitable decision-making, and improves access to finance and technology.
    These functions can be promoted by climate-relevant laws and plans, which are
    growing in number across sectors and regions, advancing mitigation outcomes and
    adaptation benefits . Climate laws have been growing in number and have helped
    deliver mitigation and adaptation outcomes .  Effective municipal, national and
    sub-national climate institutions, such as expert and co-ordinating bodies, enable
    co-produced, multi-scale decision-processes, build consensus for action among
    diverse interests, and inform strategy settings . This requires adequate institutional
    capacity at all levels. Vulnerabilities and climate risks are often reduced through
    carefully designed and implemented laws, policies, participatory processes, and
    interventions that address context specific inequities such as based on gender,
    ethnicity, disability, age, location and income. Policy support is influenced
    by Indigenous Peoples, businesses, and actors in civil society, including, youth,
    labour, media, and local communities, and effectiveness is enhanced by partnerships
    between many different groups in society . Climate-related litigation is growing,
    with a large number of cases in some developed countries and with a much smaller
    number in some developing countries, and in some cases has influenced the outcome
    and ambition of climate governance.  Effective climate governance is enabled by
    inclusive decision processes, allocation of appropriate resources, and institutional
    review, monitoring and evaluation. Multi-level, hybrid and cross-sector governance
    facilitates appropriate consideration for co-benefits and trade-offs, particularly
    in land sectors where decision processes range from farm level to national scale.
    Consideration of climate justice can help to facilitate shifting development pathways
    towards sustainability.  Drawing on diverse knowledge and partnerships, including
    with women, youth, Indigenous Peoples, local communities, and ethnic minorities
    can facilitate climate resilient development and has allowed locally appropriate
    and socially acceptable solutions.  Many regulatory and economic instruments have
    already been deployed successfully. These instruments could support deep emissions
    reductions if scaled up and applied more widely. Practical experience has informed
    instrument design and helped to improve predictability, environmental effectiveness,
    economic efficiency, and equity.  Scaling up and enhancing the use of regulatory
    instruments, consistent with national circumstances, can improve mitigation outcomes
    in sectoral applications, and regulatory instruments that include flexibility
    mechanisms can reduce costs of cutting emissions.  Where implemented, carbon pricing
    instruments have incentivized low-cost emissions reduction measures, but have
    been less effective, on their own and at prevailing prices during the assessment
    period, to promote higher-cost measures necessary for further reductions. Revenue
    from carbon taxes or emissions trading can be used for equity and distributional
    goals, for example to support low-income households, among other approaches. There
    is no consistent evidence that current emission trading systems have led to significant
    emissions leakage.  Removing fossil fuel subsidies would reduce emissions, improve
    public revenue and macroeconomic performance, and yield other environmental and
    sustainable development benefits such as improved public revenue, macroeconomic
    and sustainability performance; subsidy removal can have adverse distributional
    impacts especially on the most economically vulnerable groups which, in some cases,
    can be mitigated by measures such as re-distributing revenue saved, and depend
    on national circumstances. Fossil fuel subsidy removal is projected by various
    studies to reduce global CO 2 emissions by 1–4%, and GHG emissions by up to 10%
    by 2030, varying across regions .  National policies to support technology development,
    and participation in international markets for emission reduction, can bring positive
    spillover effects for other countries , although reduced demand for fossil fuels
    as a result of climate policy could result in costs to exporting countries . Economy-wide
    packages can meet short-term economic goals while reducing emissions and shifting
    development pathways towards sustainability. Examples are public spending commitments;
    pricing reforms; and investment in education and training, R&D and infrastructure.
    Effective policy packages would be comprehensive in coverage, harnessed to a clear
    vision for change, balanced across objectives, aligned with specific technology
    and system needs, consistent in terms of design and tailored to national circumstances
    .
  C.6.2:
  - Responses Undertaken to Date  International climate agreements, rising national
    ambitions for climate action, along with rising public awareness are accelerating
    efforts to address climate change at multiple levels of governance. Mitigation
    policies have contributed to a decrease in global energy and carbon intensity,
    with several countries achieving GHG emission reductions for over a decade. Low-emission
    technologies are becoming more affordable, with many low or zero emissions options
    now available for energy, buildings, transport, and industry. Adaptation planning
    and implementation progress has generated multiple benefits, with effective adaptation
    options having the potential to reduce climate risks and contribute to sustainable
    development. Global tracked finance for mitigation and adaptation has seen an
    upward trend since AR5, but falls short of needs.
  - Governance and Policy for Near-Term Climate Change Action  Effective climate action
    requires political commitment, well-aligned multi-level governance and institutional
    frameworks, laws, policies and strategies. It needs clear goals, adequate finance
    and financing tools, coordination across multiple policy domains, and inclusive
    governance processes. Many mitigation and adaptation policy instruments have been
    deployed successfully, and could support deep emissions reductions and climate
    resilience if scaled up and applied widely, depending on national circumstances.
    Adaptation and mitigation action benefits from drawing on diverse knowledge. Effective
    climate governance enables mitigation and adaptation by providing overall direction
    based on national circumstances, setting targets and priorities, mainstreaming
    climate action across policy domains and levels, based on national circumstances
    and in the context of international cooperation. Effective governance enhances
    monitoring and evaluation and regulatory certainty, prioritising inclusive, transparent
    and equitable decision-making, and improves access to finance and technology.
    These functions can be promoted by climate-relevant laws and plans, which are
    growing in number across sectors and regions, advancing mitigation outcomes and
    adaptation benefits . Climate laws have been growing in number and have helped
    deliver mitigation and adaptation outcomes .  Effective municipal, national and
    sub-national climate institutions, such as expert and co-ordinating bodies, enable
    co-produced, multi-scale decision-processes, build consensus for action among
    diverse interests, and inform strategy settings . This requires adequate institutional
    capacity at all levels. Vulnerabilities and climate risks are often reduced through
    carefully designed and implemented laws, policies, participatory processes, and
    interventions that address context specific inequities such as based on gender,
    ethnicity, disability, age, location and income. Policy support is influenced
    by Indigenous Peoples, businesses, and actors in civil society, including, youth,
    labour, media, and local communities, and effectiveness is enhanced by partnerships
    between many different groups in society . Climate-related litigation is growing,
    with a large number of cases in some developed countries and with a much smaller
    number in some developing countries, and in some cases has influenced the outcome
    and ambition of climate governance.  Effective climate governance is enabled by
    inclusive decision processes, allocation of appropriate resources, and institutional
    review, monitoring and evaluation. Multi-level, hybrid and cross-sector governance
    facilitates appropriate consideration for co-benefits and trade-offs, particularly
    in land sectors where decision processes range from farm level to national scale.
    Consideration of climate justice can help to facilitate shifting development pathways
    towards sustainability.  Drawing on diverse knowledge and partnerships, including
    with women, youth, Indigenous Peoples, local communities, and ethnic minorities
    can facilitate climate resilient development and has allowed locally appropriate
    and socially acceptable solutions.  Many regulatory and economic instruments have
    already been deployed successfully. These instruments could support deep emissions
    reductions if scaled up and applied more widely. Practical experience has informed
    instrument design and helped to improve predictability, environmental effectiveness,
    economic efficiency, and equity.  Scaling up and enhancing the use of regulatory
    instruments, consistent with national circumstances, can improve mitigation outcomes
    in sectoral applications, and regulatory instruments that include flexibility
    mechanisms can reduce costs of cutting emissions.  Where implemented, carbon pricing
    instruments have incentivized low-cost emissions reduction measures, but have
    been less effective, on their own and at prevailing prices during the assessment
    period, to promote higher-cost measures necessary for further reductions. Revenue
    from carbon taxes or emissions trading can be used for equity and distributional
    goals, for example to support low-income households, among other approaches. There
    is no consistent evidence that current emission trading systems have led to significant
    emissions leakage.  Removing fossil fuel subsidies would reduce emissions, improve
    public revenue and macroeconomic performance, and yield other environmental and
    sustainable development benefits such as improved public revenue, macroeconomic
    and sustainability performance; subsidy removal can have adverse distributional
    impacts especially on the most economically vulnerable groups which, in some cases,
    can be mitigated by measures such as re-distributing revenue saved, and depend
    on national circumstances. Fossil fuel subsidy removal is projected by various
    studies to reduce global CO 2 emissions by 1–4%, and GHG emissions by up to 10%
    by 2030, varying across regions .  National policies to support technology development,
    and participation in international markets for emission reduction, can bring positive
    spillover effects for other countries , although reduced demand for fossil fuels
    as a result of climate policy could result in costs to exporting countries . Economy-wide
    packages can meet short-term economic goals while reducing emissions and shifting
    development pathways towards sustainability. Examples are public spending commitments;
    pricing reforms; and investment in education and training, R&D and infrastructure.
    Effective policy packages would be comprehensive in coverage, harnessed to a clear
    vision for change, balanced across objectives, aligned with specific technology
    and system needs, consistent in terms of design and tailored to national circumstances
    .
  C.6.3:
  - Equity and Inclusion in Climate Change Action  Actions that prioritise equity,
    climate justice, social justice and inclusion lead to more sustainable outcomes,
    co-benefits, reduce trade-offs, support transformative change and advance climate
    resilient development. Adaptation responses are immediately needed to reduce rising
    climate risks, especially for the most vulnerable. Equity, inclusion and just
    transitions are key to progress on adaptation and deeper societal ambitions for
    accelerated mitigation. Adaptation and mitigation actions, across scales, sectors
    and regions, that prioritise equity, climate justice, rights-based approaches,
    social justice and inclusivity, lead to more sustainable outcomes, reduce trade-offs,
    support transformative change and advance climate resilient development . Redistributive
    policies across sectors and regions that shield the poor and vulnerable, social
    safety nets, equity, inclusion and just transitions, at all scales can enable
    deeper societal ambitions and resolve trade-offs with sustainable development
    goals., particularly education, hunger, poverty, gender and energy access . Mitigation
    efforts embedded within the wider development context can increase the pace, depth
    and breadth of emission reductions . Equity, inclusion and just transitions at
    all scales enable deeper societal ambitions for accelerated mitigation, and climate
    action more broadly. The complexity in risk of rising food prices, reduced household
    incomes, and health and climate-related malnutrition  and mortality increases
    with little or low levels of adaptation.  Regions and people with considerable
    development constraints have high vulnerability to climatic hazards. Adaptation
    outcomes for the most vulnerable within and across countries and regions are enhanced
    through approaches focusing on equity, inclusivity, and rights-based approaches,
    including 3.3 to 3.6 billion people living in contexts that are highly vulnerable
    to climate change. Vulnerability is higher in locations with poverty, governance
    challenges and limited access to basic services and resources, violent conflict
    and high levels of climate-sensitive livelihoods  . Several risks can be moderated
    with adaptation. The largest adaptation gaps exist among lower income population
    groups and adaptation progress is unevenly distributed with observed adaptation
    gaps. Present development challenges causing high vulnerability are influenced
    by historical and ongoing patterns of inequity such as colonialism, especially
    for many Indigenous Peoples and local communities. Vulnerability is exacerbated
    by inequity and marginalisation linked to gender, ethnicity, low income or combinations
    thereof, especially for many Indigenous Peoples and local communities.  Meaningful
    participation and inclusive planning, informed by cultural values, Indigenous
    Knowledge, local knowledge, and scientific knowledge can help address adaptation
    gaps and avoid maladaptation. Such actions with flexible pathways may encourage
    low-regret and timely actions . Integrating climate adaptation into social protection
    programmes, including cash transfers and public works programmes, would increase
    resilience to climate change, especially when supported by basic services and
    infrastructure.  Equity, inclusion, just transitions, broad and meaningful participation
    of all relevant actors in decision making at all scales enable deeper societal
    ambitions for accelerated mitigation, and climate action more broadly, and build
    social trust, support transformative changes and an equitable sharing of benefits
    and burdens. Equity remains a central element in the UN climate regime, notwithstanding
    shifts in differentiation between states over time and challenges in assessing
    fair shares. Ambitious mitigation pathways imply large and sometimes disruptive
    changes in economic structure, with significant distributional consequences, within
    and between countries, including shifting of income and employment during the
    transition from high to low emissions activities. While some jobs may be lost,
    low-emissions development can also open up opportunities to enhance skills and
    create jobs. Broadening equitable access to finance, technologies and governance
    that facilitate mitigation, and consideration of climate justice can help equitable
    sharing of benefits and burdens, especially for vulnerable countries and communities.  Development
    priorities among countries also reflect different starting points and contexts,
    and enabling conditions for shifting development pathways towards increased sustainability
    will therefore differ, giving rise to different needs . Implementing just transition
    principles through collective and participatory decision-making processes is an
    effective way of integrating equity principles into policies at all scales depending
    on national circumstances, while in several countries just transition commissions,
    task forces and national policies have been established .  Many economic and regulatory
    instruments have been effective in reducing emissions and practical experience
    has informed instrument design to improve them while addressing distributional
    goals and social acceptance. The design of behavioural interventions, including
    the way that choices are presented to consumers work synergistically with price
    signals, making the combination more effective. Individuals with high socio-economic
    status contribute disproportionately to emissions, and have the highest potential
    for emissions reductions, e.g., as citizens, investors, consumers, role models,
    and professionals . There are options on design of instruments such as taxes,
    subsidies, prices, and consumption-based approaches, complemented by regulatory
    instruments to reduce high-emissions consumption while improving equity and societal
    well-being. Behaviour and lifestyle changes to help end-users adopt low-GHG-intensive
    options can be supported by policies, infrastructure and technology with multiple
    co-benefits for societal well-being. Broadening equitable access to domestic and
    international finance, technologies and capacity can also act as a catalyst for
    accelerating mitigation and shifting development pathways in low-income contexts
    . Eradicating extreme poverty, energy poverty, and providing decent living standards
    to all in these regions in the context of achieving sustainable development objectives,
    in the near term, can be achieved without significant global emissions growth.
    Technology development, transfer, capacity building and financing can support
    developing countries/ regions leapfrogging or transitioning to low-emissions transport
    systems thereby providing multiple co-benefits . Climate resilient development
    is advanced when actors work in equitable, just and enabling ways to reconcile
    divergent interests, values and worldviews, toward equitable and just outcomes
    .
  - Governance and Policy for Near-Term Climate Change Action  Effective climate action
    requires political commitment, well-aligned multi-level governance and institutional
    frameworks, laws, policies and strategies. It needs clear goals, adequate finance
    and financing tools, coordination across multiple policy domains, and inclusive
    governance processes. Many mitigation and adaptation policy instruments have been
    deployed successfully, and could support deep emissions reductions and climate
    resilience if scaled up and applied widely, depending on national circumstances.
    Adaptation and mitigation action benefits from drawing on diverse knowledge. Effective
    climate governance enables mitigation and adaptation by providing overall direction
    based on national circumstances, setting targets and priorities, mainstreaming
    climate action across policy domains and levels, based on national circumstances
    and in the context of international cooperation. Effective governance enhances
    monitoring and evaluation and regulatory certainty, prioritising inclusive, transparent
    and equitable decision-making, and improves access to finance and technology.
    These functions can be promoted by climate-relevant laws and plans, which are
    growing in number across sectors and regions, advancing mitigation outcomes and
    adaptation benefits . Climate laws have been growing in number and have helped
    deliver mitigation and adaptation outcomes .  Effective municipal, national and
    sub-national climate institutions, such as expert and co-ordinating bodies, enable
    co-produced, multi-scale decision-processes, build consensus for action among
    diverse interests, and inform strategy settings . This requires adequate institutional
    capacity at all levels. Vulnerabilities and climate risks are often reduced through
    carefully designed and implemented laws, policies, participatory processes, and
    interventions that address context specific inequities such as based on gender,
    ethnicity, disability, age, location and income. Policy support is influenced
    by Indigenous Peoples, businesses, and actors in civil society, including, youth,
    labour, media, and local communities, and effectiveness is enhanced by partnerships
    between many different groups in society . Climate-related litigation is growing,
    with a large number of cases in some developed countries and with a much smaller
    number in some developing countries, and in some cases has influenced the outcome
    and ambition of climate governance.  Effective climate governance is enabled by
    inclusive decision processes, allocation of appropriate resources, and institutional
    review, monitoring and evaluation. Multi-level, hybrid and cross-sector governance
    facilitates appropriate consideration for co-benefits and trade-offs, particularly
    in land sectors where decision processes range from farm level to national scale.
    Consideration of climate justice can help to facilitate shifting development pathways
    towards sustainability.  Drawing on diverse knowledge and partnerships, including
    with women, youth, Indigenous Peoples, local communities, and ethnic minorities
    can facilitate climate resilient development and has allowed locally appropriate
    and socially acceptable solutions.  Many regulatory and economic instruments have
    already been deployed successfully. These instruments could support deep emissions
    reductions if scaled up and applied more widely. Practical experience has informed
    instrument design and helped to improve predictability, environmental effectiveness,
    economic efficiency, and equity.  Scaling up and enhancing the use of regulatory
    instruments, consistent with national circumstances, can improve mitigation outcomes
    in sectoral applications, and regulatory instruments that include flexibility
    mechanisms can reduce costs of cutting emissions.  Where implemented, carbon pricing
    instruments have incentivized low-cost emissions reduction measures, but have
    been less effective, on their own and at prevailing prices during the assessment
    period, to promote higher-cost measures necessary for further reductions. Revenue
    from carbon taxes or emissions trading can be used for equity and distributional
    goals, for example to support low-income households, among other approaches. There
    is no consistent evidence that current emission trading systems have led to significant
    emissions leakage.  Removing fossil fuel subsidies would reduce emissions, improve
    public revenue and macroeconomic performance, and yield other environmental and
    sustainable development benefits such as improved public revenue, macroeconomic
    and sustainability performance; subsidy removal can have adverse distributional
    impacts especially on the most economically vulnerable groups which, in some cases,
    can be mitigated by measures such as re-distributing revenue saved, and depend
    on national circumstances. Fossil fuel subsidy removal is projected by various
    studies to reduce global CO 2 emissions by 1–4%, and GHG emissions by up to 10%
    by 2030, varying across regions .  National policies to support technology development,
    and participation in international markets for emission reduction, can bring positive
    spillover effects for other countries , although reduced demand for fossil fuels
    as a result of climate policy could result in costs to exporting countries . Economy-wide
    packages can meet short-term economic goals while reducing emissions and shifting
    development pathways towards sustainability. Examples are public spending commitments;
    pricing reforms; and investment in education and training, R&D and infrastructure.
    Effective policy packages would be comprehensive in coverage, harnessed to a clear
    vision for change, balanced across objectives, aligned with specific technology
    and system needs, consistent in terms of design and tailored to national circumstances
    .
  C.6.4:
  - Mitigation Actions to Date  There has been a consistent expansion of policies
    and laws addressing mitigation since AR5. Climate governance supports mitigation
    by providing frameworks through which diverse actors interact, and a basis for
    policy development and implementation. Many regulatory and economic instruments
    have already been deployed successfully. By 2020, laws primarily focussed on reducing
    GHG emissions existed in 56 countries covering 53% of global emissions. The application
    of diverse policy instruments for mitigation at the national and sub-national
    levels has grown consistently across a range of sectors. Policy coverage is uneven
    across sectors and remains limited for emissions from agriculture, and from industrial
    materials and feedstocks.  Practical experience has informed economic instrument
    design and helped to improve predictability, environmental effectiveness, economic
    efficiency, alignment with distributional goals, and social acceptance. Low-emission
    technological innovation is strengthened through the combination of technology-push
    policies, together with policies that create incentives for behaviour change and
    market opportunities. Comprehensive and consistent policy packages have been found
    to be more effective than single policies. Combining mitigation with policies
    to shift development pathways, policies that induce lifestyle or behaviour changes,
    for example, measures promoting walkable urban areas combined with electrification
    and renewable energy can create health co-benefits from cleaner air and enhanced
    active mobility . Climate governance enables mitigation by providing an overall
    direction, setting targets, mainstreaming climate action across policy domains
    and levels, based on national circumstances and in the context of international
    cooperation. Effective governance enhances regulatory certainty, creating specialised
    organisations and creating the context to mobilise finance. These functions can
    be promoted by climate-relevant laws, which are growing in number, or climate
    strategies, among others, based on national and sub-national context. Effective
    and equitable climate governance builds on engagement with civil society actors,
    political actors, businesses, youth, labour, media, Indigenous Peoples and local
    communities.  The unit costs of several low-emission technologies, including solar,
    wind and lithium-ion batteries, have fallen consistently since 2010. Design and
    process innovations in combination with the use of digital technologies have led
    to near-commercial availability of many low or zero emissions options in buildings,
    transport and industry. From 2010-2019, there have been sustained decreases in
    the unit costs of solar energy , wind energy, and lithium-ion batteries, and large
    increases in their deployment, e.g., >10× for solar and >100× for electric vehicles,
    albeit varying widely across regions. Electricity from PV and wind is now cheaper
    than electricity from fossil sources in many regions, electric vehicles are increasingly
    competitive with internal combustion engines, and large-scale battery storage
    on electricity grids is increasingly viable. In comparison to modular small-unit
    size technologies, the empirical record shows that multiple large-scale mitigation
    technologies, with fewer opportunities for learning, have seen minimal cost reductions
    and their adoption has grown slowly. Maintaining emission-intensive systems may,
    in some regions and sectors, be more expensive than transitioning to low emission
    systems.  For almost all basic materials – primary metals, building materials
    and chemicals – many low- to zero-GHG intensity production processes are at the
    pilot to near-commercial and in some cases commercial stage but they are not yet
    established industrial practice. Integrated design in construction and retrofit
    of buildings has led to increasing examples of zero energy or zero carbon buildings.
    Technological innovation made possible the widespread adoption of LED lighting.
    Digital technologies including sensors, the internet of things, robotics, and
    artificial intelligence can improve energy management in all sectors; they can
    increase energy efficiency, and promote the adoption of many low-emission technologies,
    including decentralised renewable energy, while creating economic opportunities.
    However, some of these climate change mitigation gains can be reduced or counterbalanced
    by growth in demand for goods and services due to the use of digital devices.
    Several mitigation options, notably solar energy, wind energy, electrification
    of urban systems, urban green infrastructure, energy efficiency, demand side management,
    improved forest- and crop/grassland management, and reduced food waste and loss,
    are technically viable, are becoming increasingly cost effective and are generally
    supported by the public, and this enables expanded deployment in many regions.  The
    magnitude of global climate finance flows has increased and financing channels
    have broadened. Annual tracked total financial flows for climate mitigation and
    adaptation increased by up to 60% between 2013/14 and 2019/20, but average growth
    has slowed since 2018 and most climate finance stays within national borders.
    Markets for green bonds, environmental, social and governance and sustainable
    finance products have expanded significantly since AR5 . Investors, central banks,
    and financial regulators are driving increased awareness of climate risk to support
    climate policy development and implementation. Accelerated international financial
    cooperation is a critical enabler of low-GHG and just transitions.  Economic instruments
    have been effective in reducing emissions, complemented by regulatory instruments
    mainly at the national and also sub-national and regional level. By 2020, over
    20% of global GHG emissions were covered by carbon taxes or emissions trading
    systems, although coverage and prices have been insufficient to achieve deep reductions.
    Equity and distributional impacts of carbon pricing instruments can be addressed
    by using revenue from carbon taxes or emissions trading to support low-income
    households, among other approaches. The mix of policy instruments which reduced
    costs and stimulated adoption of solar energy, wind energy and lithium-ion batteries
    includes public R&D, funding for demonstration and pilot projects, and demand-pull
    instruments such as deployment subsidies to attain scale .  Mitigation actions,
    supported by policies, have contributed to a decrease in global energy and carbon
    intensity between 2010 and 2019, with a growing number of countries achieving
    absolute GHG emission reductions for more than a decade . While global net GHG
    emissions have increased since 2010, global energy intensity decreased by 2% yr
    –1 between 2010 and 2019. Global carbon intensity also decreased by 0.3% yr –1
    , mainly due to fuel switching from coal to gas, reduced expansion of coal capacity,
    and increased use of renewables, and with large regional variations over the same
    period. In many countries, policies have enhanced energy efficiency, reduced rates
    of deforestation and accelerated technology deployment, leading to avoided and
    in some cases reduced or removed emissions. At least 18 countries have sustained
    production-based CO2 and GHG and consumption-based CO2 absolute emission reductions
    for longer than 10 years since 2005 through energy supply decarbonization, energy
    efficiency gains, and energy demand reduction, which resulted from both policies
    and changes in economic structure. Some countries have reduced production-based
    GHG emissions by a third or more since peaking, and some have achieved reduction
    rates of around 4% yr–1 for several years consecutively. Multiple lines of evidence
    suggest that mitigation policies have led to avoided global emissions of several
    GtCO 2-eq yr–1. At least 1.8 GtCO2-eq yr–1 of avoided emissions can be accounted
    for by aggregating separate estimates for the effects of economic and regulatory
    instruments. Growing numbers of laws and executive orders have impacted global
    emissions and are estimated to have resulted in 5.9 GtCO2 -eq yr–1 of avoided
    emissions in 2016. These reductions have only partly offset global emissions growth.
  - Governance and Policy for Near-Term Climate Change Action  Effective climate action
    requires political commitment, well-aligned multi-level governance and institutional
    frameworks, laws, policies and strategies. It needs clear goals, adequate finance
    and financing tools, coordination across multiple policy domains, and inclusive
    governance processes. Many mitigation and adaptation policy instruments have been
    deployed successfully, and could support deep emissions reductions and climate
    resilience if scaled up and applied widely, depending on national circumstances.
    Adaptation and mitigation action benefits from drawing on diverse knowledge. Effective
    climate governance enables mitigation and adaptation by providing overall direction
    based on national circumstances, setting targets and priorities, mainstreaming
    climate action across policy domains and levels, based on national circumstances
    and in the context of international cooperation. Effective governance enhances
    monitoring and evaluation and regulatory certainty, prioritising inclusive, transparent
    and equitable decision-making, and improves access to finance and technology.
    These functions can be promoted by climate-relevant laws and plans, which are
    growing in number across sectors and regions, advancing mitigation outcomes and
    adaptation benefits . Climate laws have been growing in number and have helped
    deliver mitigation and adaptation outcomes .  Effective municipal, national and
    sub-national climate institutions, such as expert and co-ordinating bodies, enable
    co-produced, multi-scale decision-processes, build consensus for action among
    diverse interests, and inform strategy settings . This requires adequate institutional
    capacity at all levels. Vulnerabilities and climate risks are often reduced through
    carefully designed and implemented laws, policies, participatory processes, and
    interventions that address context specific inequities such as based on gender,
    ethnicity, disability, age, location and income. Policy support is influenced
    by Indigenous Peoples, businesses, and actors in civil society, including, youth,
    labour, media, and local communities, and effectiveness is enhanced by partnerships
    between many different groups in society . Climate-related litigation is growing,
    with a large number of cases in some developed countries and with a much smaller
    number in some developing countries, and in some cases has influenced the outcome
    and ambition of climate governance.  Effective climate governance is enabled by
    inclusive decision processes, allocation of appropriate resources, and institutional
    review, monitoring and evaluation. Multi-level, hybrid and cross-sector governance
    facilitates appropriate consideration for co-benefits and trade-offs, particularly
    in land sectors where decision processes range from farm level to national scale.
    Consideration of climate justice can help to facilitate shifting development pathways
    towards sustainability.  Drawing on diverse knowledge and partnerships, including
    with women, youth, Indigenous Peoples, local communities, and ethnic minorities
    can facilitate climate resilient development and has allowed locally appropriate
    and socially acceptable solutions.  Many regulatory and economic instruments have
    already been deployed successfully. These instruments could support deep emissions
    reductions if scaled up and applied more widely. Practical experience has informed
    instrument design and helped to improve predictability, environmental effectiveness,
    economic efficiency, and equity.  Scaling up and enhancing the use of regulatory
    instruments, consistent with national circumstances, can improve mitigation outcomes
    in sectoral applications, and regulatory instruments that include flexibility
    mechanisms can reduce costs of cutting emissions.  Where implemented, carbon pricing
    instruments have incentivized low-cost emissions reduction measures, but have
    been less effective, on their own and at prevailing prices during the assessment
    period, to promote higher-cost measures necessary for further reductions. Revenue
    from carbon taxes or emissions trading can be used for equity and distributional
    goals, for example to support low-income households, among other approaches. There
    is no consistent evidence that current emission trading systems have led to significant
    emissions leakage.  Removing fossil fuel subsidies would reduce emissions, improve
    public revenue and macroeconomic performance, and yield other environmental and
    sustainable development benefits such as improved public revenue, macroeconomic
    and sustainability performance; subsidy removal can have adverse distributional
    impacts especially on the most economically vulnerable groups which, in some cases,
    can be mitigated by measures such as re-distributing revenue saved, and depend
    on national circumstances. Fossil fuel subsidy removal is projected by various
    studies to reduce global CO 2 emissions by 1–4%, and GHG emissions by up to 10%
    by 2030, varying across regions .  National policies to support technology development,
    and participation in international markets for emission reduction, can bring positive
    spillover effects for other countries , although reduced demand for fossil fuels
    as a result of climate policy could result in costs to exporting countries . Economy-wide
    packages can meet short-term economic goals while reducing emissions and shifting
    development pathways towards sustainability. Examples are public spending commitments;
    pricing reforms; and investment in education and training, R&D and infrastructure.
    Effective policy packages would be comprehensive in coverage, harnessed to a clear
    vision for change, balanced across objectives, aligned with specific technology
    and system needs, consistent in terms of design and tailored to national circumstances
    .
  C.6.5:
  - Equity and Inclusion in Climate Change Action  Actions that prioritise equity,
    climate justice, social justice and inclusion lead to more sustainable outcomes,
    co-benefits, reduce trade-offs, support transformative change and advance climate
    resilient development. Adaptation responses are immediately needed to reduce rising
    climate risks, especially for the most vulnerable. Equity, inclusion and just
    transitions are key to progress on adaptation and deeper societal ambitions for
    accelerated mitigation. Adaptation and mitigation actions, across scales, sectors
    and regions, that prioritise equity, climate justice, rights-based approaches,
    social justice and inclusivity, lead to more sustainable outcomes, reduce trade-offs,
    support transformative change and advance climate resilient development . Redistributive
    policies across sectors and regions that shield the poor and vulnerable, social
    safety nets, equity, inclusion and just transitions, at all scales can enable
    deeper societal ambitions and resolve trade-offs with sustainable development
    goals., particularly education, hunger, poverty, gender and energy access . Mitigation
    efforts embedded within the wider development context can increase the pace, depth
    and breadth of emission reductions . Equity, inclusion and just transitions at
    all scales enable deeper societal ambitions for accelerated mitigation, and climate
    action more broadly. The complexity in risk of rising food prices, reduced household
    incomes, and health and climate-related malnutrition  and mortality increases
    with little or low levels of adaptation.  Regions and people with considerable
    development constraints have high vulnerability to climatic hazards. Adaptation
    outcomes for the most vulnerable within and across countries and regions are enhanced
    through approaches focusing on equity, inclusivity, and rights-based approaches,
    including 3.3 to 3.6 billion people living in contexts that are highly vulnerable
    to climate change. Vulnerability is higher in locations with poverty, governance
    challenges and limited access to basic services and resources, violent conflict
    and high levels of climate-sensitive livelihoods  . Several risks can be moderated
    with adaptation. The largest adaptation gaps exist among lower income population
    groups and adaptation progress is unevenly distributed with observed adaptation
    gaps. Present development challenges causing high vulnerability are influenced
    by historical and ongoing patterns of inequity such as colonialism, especially
    for many Indigenous Peoples and local communities. Vulnerability is exacerbated
    by inequity and marginalisation linked to gender, ethnicity, low income or combinations
    thereof, especially for many Indigenous Peoples and local communities.  Meaningful
    participation and inclusive planning, informed by cultural values, Indigenous
    Knowledge, local knowledge, and scientific knowledge can help address adaptation
    gaps and avoid maladaptation. Such actions with flexible pathways may encourage
    low-regret and timely actions . Integrating climate adaptation into social protection
    programmes, including cash transfers and public works programmes, would increase
    resilience to climate change, especially when supported by basic services and
    infrastructure.  Equity, inclusion, just transitions, broad and meaningful participation
    of all relevant actors in decision making at all scales enable deeper societal
    ambitions for accelerated mitigation, and climate action more broadly, and build
    social trust, support transformative changes and an equitable sharing of benefits
    and burdens. Equity remains a central element in the UN climate regime, notwithstanding
    shifts in differentiation between states over time and challenges in assessing
    fair shares. Ambitious mitigation pathways imply large and sometimes disruptive
    changes in economic structure, with significant distributional consequences, within
    and between countries, including shifting of income and employment during the
    transition from high to low emissions activities. While some jobs may be lost,
    low-emissions development can also open up opportunities to enhance skills and
    create jobs. Broadening equitable access to finance, technologies and governance
    that facilitate mitigation, and consideration of climate justice can help equitable
    sharing of benefits and burdens, especially for vulnerable countries and communities.  Development
    priorities among countries also reflect different starting points and contexts,
    and enabling conditions for shifting development pathways towards increased sustainability
    will therefore differ, giving rise to different needs . Implementing just transition
    principles through collective and participatory decision-making processes is an
    effective way of integrating equity principles into policies at all scales depending
    on national circumstances, while in several countries just transition commissions,
    task forces and national policies have been established .  Many economic and regulatory
    instruments have been effective in reducing emissions and practical experience
    has informed instrument design to improve them while addressing distributional
    goals and social acceptance. The design of behavioural interventions, including
    the way that choices are presented to consumers work synergistically with price
    signals, making the combination more effective. Individuals with high socio-economic
    status contribute disproportionately to emissions, and have the highest potential
    for emissions reductions, e.g., as citizens, investors, consumers, role models,
    and professionals . There are options on design of instruments such as taxes,
    subsidies, prices, and consumption-based approaches, complemented by regulatory
    instruments to reduce high-emissions consumption while improving equity and societal
    well-being. Behaviour and lifestyle changes to help end-users adopt low-GHG-intensive
    options can be supported by policies, infrastructure and technology with multiple
    co-benefits for societal well-being. Broadening equitable access to domestic and
    international finance, technologies and capacity can also act as a catalyst for
    accelerating mitigation and shifting development pathways in low-income contexts
    . Eradicating extreme poverty, energy poverty, and providing decent living standards
    to all in these regions in the context of achieving sustainable development objectives,
    in the near term, can be achieved without significant global emissions growth.
    Technology development, transfer, capacity building and financing can support
    developing countries/ regions leapfrogging or transitioning to low-emissions transport
    systems thereby providing multiple co-benefits . Climate resilient development
    is advanced when actors work in equitable, just and enabling ways to reconcile
    divergent interests, values and worldviews, toward equitable and just outcomes
    .
  - Society, Livelihoods, and Economies  Enhancing knowledge on risks and available
    adaptation options promotes societal responses, and behaviour and lifestyle changes
    supported by policies, infrastructure and technology can help reduce global GHG
    emissions. Climate literacy and information provided through climate services
    and community approaches, including those that are informed by Indigenous Knowledge
    and local knowledge, can accelerate behavioural changes and planning . Educational
    and information programmes, using the arts, participatory modelling and citizen
    science can facilitate awareness, heighten risk perception, and influence behaviours
    . The way choices are presented can enable adoption of low GHG intensive socio-cultural
    options, such as shifts to balanced, sustainable healthy diets, reduced food waste,
    and active mobility. Judicious labelling, framing, and communication of social
    norms can increase the effect of mandates, subsidies, or taxes.  A range of adaptation
    options, such as disaster risk management, early warning systems, climate services
    and risk spreading and sharing approaches, have broad applicability across sectors
    and provide greater risk reduction benefits when combined . Climate services that
    are demand-driven and inclusive of different users and providers can improve agricultural
    practices, inform better water use and efficiency, and enable resilient infrastructure
    planning. Policy mixes that include weather and health insurance, social protection
    and adaptive safety nets, contingent finance and reserve funds, and universal
    access to early warning systems combined with effective contingency plans, can
    reduce vulnerability and exposure of human systems. Integrating climate adaptation
    into social protection programs, including cash transfers and public works programs,
    is highly feasible and increases resilience to climate change, especially when
    supported by basic services and infrastructure. Social safety nets can build adaptive
    capacities, reduce socioeconomic vulnerability, and reduce risk linked to hazards.  Reducing
    future risks of involuntary migration and displacement due to climate change is
    possible through cooperative, international efforts to enhance institutional adaptive
    capacity and sustainable development. Increasing adaptive capacity minimises risk
    associated with involuntary migration and immobility and improves the degree of
    choice under which migration decisions are made, while policy interventions can
    remove barriers and expand the alternatives for safe, orderly and regular migration
    that allows vulnerable people to adapt to climate change.  Accelerating commitment
    and follow-through by the private sector is promoted for instance by building
    business cases for adaptation, accountability and transparency mechanisms, and
    monitoring and evaluation of adaptation progress . Integrated pathways for managing
    climate risks will be most suitable when so-called ‘low-regret’ anticipatory options
    are established jointly across sectors in a timely manner and are feasible and
    effective in their local context, and when path dependencies and maladaptations
    across sectors are avoided. Sustained adaptation actions are strengthened by mainstreaming
    adaptation into institutional budget and policy planning cycles, statutory planning,
    monitoring and evaluation frameworks and into recovery efforts from disaster events.
    Instruments that incorporate adaptation such as policy and legal frameworks, behavioural
    incentives, and economic instruments that address market failures, such as climate
    risk disclosure, inclusive and deliberative processes strengthen adaptation actions
    by public and private actors.
  - Governance and Policy for Near-Term Climate Change Action  Effective climate action
    requires political commitment, well-aligned multi-level governance and institutional
    frameworks, laws, policies and strategies. It needs clear goals, adequate finance
    and financing tools, coordination across multiple policy domains, and inclusive
    governance processes. Many mitigation and adaptation policy instruments have been
    deployed successfully, and could support deep emissions reductions and climate
    resilience if scaled up and applied widely, depending on national circumstances.
    Adaptation and mitigation action benefits from drawing on diverse knowledge. Effective
    climate governance enables mitigation and adaptation by providing overall direction
    based on national circumstances, setting targets and priorities, mainstreaming
    climate action across policy domains and levels, based on national circumstances
    and in the context of international cooperation. Effective governance enhances
    monitoring and evaluation and regulatory certainty, prioritising inclusive, transparent
    and equitable decision-making, and improves access to finance and technology.
    These functions can be promoted by climate-relevant laws and plans, which are
    growing in number across sectors and regions, advancing mitigation outcomes and
    adaptation benefits . Climate laws have been growing in number and have helped
    deliver mitigation and adaptation outcomes .  Effective municipal, national and
    sub-national climate institutions, such as expert and co-ordinating bodies, enable
    co-produced, multi-scale decision-processes, build consensus for action among
    diverse interests, and inform strategy settings . This requires adequate institutional
    capacity at all levels. Vulnerabilities and climate risks are often reduced through
    carefully designed and implemented laws, policies, participatory processes, and
    interventions that address context specific inequities such as based on gender,
    ethnicity, disability, age, location and income. Policy support is influenced
    by Indigenous Peoples, businesses, and actors in civil society, including, youth,
    labour, media, and local communities, and effectiveness is enhanced by partnerships
    between many different groups in society . Climate-related litigation is growing,
    with a large number of cases in some developed countries and with a much smaller
    number in some developing countries, and in some cases has influenced the outcome
    and ambition of climate governance.  Effective climate governance is enabled by
    inclusive decision processes, allocation of appropriate resources, and institutional
    review, monitoring and evaluation. Multi-level, hybrid and cross-sector governance
    facilitates appropriate consideration for co-benefits and trade-offs, particularly
    in land sectors where decision processes range from farm level to national scale.
    Consideration of climate justice can help to facilitate shifting development pathways
    towards sustainability.  Drawing on diverse knowledge and partnerships, including
    with women, youth, Indigenous Peoples, local communities, and ethnic minorities
    can facilitate climate resilient development and has allowed locally appropriate
    and socially acceptable solutions.  Many regulatory and economic instruments have
    already been deployed successfully. These instruments could support deep emissions
    reductions if scaled up and applied more widely. Practical experience has informed
    instrument design and helped to improve predictability, environmental effectiveness,
    economic efficiency, and equity.  Scaling up and enhancing the use of regulatory
    instruments, consistent with national circumstances, can improve mitigation outcomes
    in sectoral applications, and regulatory instruments that include flexibility
    mechanisms can reduce costs of cutting emissions.  Where implemented, carbon pricing
    instruments have incentivized low-cost emissions reduction measures, but have
    been less effective, on their own and at prevailing prices during the assessment
    period, to promote higher-cost measures necessary for further reductions. Revenue
    from carbon taxes or emissions trading can be used for equity and distributional
    goals, for example to support low-income households, among other approaches. There
    is no consistent evidence that current emission trading systems have led to significant
    emissions leakage.  Removing fossil fuel subsidies would reduce emissions, improve
    public revenue and macroeconomic performance, and yield other environmental and
    sustainable development benefits such as improved public revenue, macroeconomic
    and sustainability performance; subsidy removal can have adverse distributional
    impacts especially on the most economically vulnerable groups which, in some cases,
    can be mitigated by measures such as re-distributing revenue saved, and depend
    on national circumstances. Fossil fuel subsidy removal is projected by various
    studies to reduce global CO 2 emissions by 1–4%, and GHG emissions by up to 10%
    by 2030, varying across regions .  National policies to support technology development,
    and participation in international markets for emission reduction, can bring positive
    spillover effects for other countries , although reduced demand for fossil fuels
    as a result of climate policy could result in costs to exporting countries . Economy-wide
    packages can meet short-term economic goals while reducing emissions and shifting
    development pathways towards sustainability. Examples are public spending commitments;
    pricing reforms; and investment in education and training, R&D and infrastructure.
    Effective policy packages would be comprehensive in coverage, harnessed to a clear
    vision for change, balanced across objectives, aligned with specific technology
    and system needs, consistent in terms of design and tailored to national circumstances
    .
  C.7.1:
  - Finance for Mitigation and Adaptation Actions  Improved availability and access
    to finance will enable accelerated climate action. Addressing needs and gaps and
    broadening equitable access to domestic and international finance, when combined
    with other supportive actions, can act as a catalyst for accelerating mitigation
    and shifting development pathways. Climate resilient development is enabled by
    increased international cooperation including improved access to financial resources,
    particularly for vulnerable regions, sectors and groups, and inclusive governance
    and coordinated policies . Accelerated international financial cooperation is
    a critical enabler of low-GHG and just transitions, and can address inequities
    in access to finance and the costs of, and vulnerability to, the impacts of climate
    change.  Both adaptation and mitigation finance need to increase many-fold, to
    address rising climate risks and to accelerate investments in emissions reduction.
    Increased finance would address soft limits to adaptation and rising climate risks
    while also averting some related losses and damages, particularly in vulnerable
    developing countries. Enhanced mobilisation of and access to finance, together
    with building capacity, are essential for implementation of adaptation actions
    and to reduce adaptation gaps given rising risks and costs, especially for the
    most vulnerable groups, regions and sectors . Public finance is an important enabler
    of adaptation and mitigation, and can also leverage private finance. Adaptation
    funding predominately comes from public sources, and public mechanisms and finance
    can leverage private sector finance by addressing real and perceived regulatory,
    cost and market barriers, for instance via public-private partnerships. Financial
    and technological resources enable effective and ongoing implementation of adaptation,
    especially when supported by institutions with a strong understanding of adaptation
    needs and capacity. Average annual modelled mitigation investment requirements
    for 2020 to 2030 in scenarios that limit warming to 2°C or 1.5°C are a factor
    of three to six greater than current levels, and total mitigation investments
    would need to increase across all sectors and regions. Even if extensive global
    mitigation efforts are implemented, there will be a large need for financial,
    technical, and human resources for adaptation .
  C.7.3:
  - Finance for Mitigation and Adaptation Actions  Improved availability and access
    to finance will enable accelerated climate action. Addressing needs and gaps and
    broadening equitable access to domestic and international finance, when combined
    with other supportive actions, can act as a catalyst for accelerating mitigation
    and shifting development pathways. Climate resilient development is enabled by
    increased international cooperation including improved access to financial resources,
    particularly for vulnerable regions, sectors and groups, and inclusive governance
    and coordinated policies . Accelerated international financial cooperation is
    a critical enabler of low-GHG and just transitions, and can address inequities
    in access to finance and the costs of, and vulnerability to, the impacts of climate
    change.  Both adaptation and mitigation finance need to increase many-fold, to
    address rising climate risks and to accelerate investments in emissions reduction.
    Increased finance would address soft limits to adaptation and rising climate risks
    while also averting some related losses and damages, particularly in vulnerable
    developing countries. Enhanced mobilisation of and access to finance, together
    with building capacity, are essential for implementation of adaptation actions
    and to reduce adaptation gaps given rising risks and costs, especially for the
    most vulnerable groups, regions and sectors . Public finance is an important enabler
    of adaptation and mitigation, and can also leverage private finance. Adaptation
    funding predominately comes from public sources, and public mechanisms and finance
    can leverage private sector finance by addressing real and perceived regulatory,
    cost and market barriers, for instance via public-private partnerships. Financial
    and technological resources enable effective and ongoing implementation of adaptation,
    especially when supported by institutions with a strong understanding of adaptation
    needs and capacity. Average annual modelled mitigation investment requirements
    for 2020 to 2030 in scenarios that limit warming to 2°C or 1.5°C are a factor
    of three to six greater than current levels, and total mitigation investments
    would need to increase across all sectors and regions. Even if extensive global
    mitigation efforts are implemented, there will be a large need for financial,
    technical, and human resources for adaptation .
  C.7.4:
  - Finance for Mitigation and Adaptation Actions  Improved availability and access
    to finance will enable accelerated climate action. Addressing needs and gaps and
    broadening equitable access to domestic and international finance, when combined
    with other supportive actions, can act as a catalyst for accelerating mitigation
    and shifting development pathways. Climate resilient development is enabled by
    increased international cooperation including improved access to financial resources,
    particularly for vulnerable regions, sectors and groups, and inclusive governance
    and coordinated policies . Accelerated international financial cooperation is
    a critical enabler of low-GHG and just transitions, and can address inequities
    in access to finance and the costs of, and vulnerability to, the impacts of climate
    change.  Both adaptation and mitigation finance need to increase many-fold, to
    address rising climate risks and to accelerate investments in emissions reduction.
    Increased finance would address soft limits to adaptation and rising climate risks
    while also averting some related losses and damages, particularly in vulnerable
    developing countries. Enhanced mobilisation of and access to finance, together
    with building capacity, are essential for implementation of adaptation actions
    and to reduce adaptation gaps given rising risks and costs, especially for the
    most vulnerable groups, regions and sectors . Public finance is an important enabler
    of adaptation and mitigation, and can also leverage private finance. Adaptation
    funding predominately comes from public sources, and public mechanisms and finance
    can leverage private sector finance by addressing real and perceived regulatory,
    cost and market barriers, for instance via public-private partnerships. Financial
    and technological resources enable effective and ongoing implementation of adaptation,
    especially when supported by institutions with a strong understanding of adaptation
    needs and capacity. Average annual modelled mitigation investment requirements
    for 2020 to 2030 in scenarios that limit warming to 2°C or 1.5°C are a factor
    of three to six greater than current levels, and total mitigation investments
    would need to increase across all sectors and regions. Even if extensive global
    mitigation efforts are implemented, there will be a large need for financial,
    technical, and human resources for adaptation .
  C.7.5:
  - 'Technology Innovation, Adoption, Diffusion and  Transfer Enhancing technology
    innovation systems can provide opportunities to lower emissions growth and create
    social and environmental co-benefits. Policy packages tailored to national contexts
    and technological characteristics have been effective in supporting low-emission
    innovation and technology diffusion. Support for successful low-carbon technological
    innovation includes public policies such as training and R&D, complemented by
    regulatory and market-based instruments that create incentives and market opportunities
    such as appliance performance standards and building codes.  International cooperation
    on innovation systems and technology development and transfer, accompanied by
    capacity building, knowledge sharing, and technical and financial support can
    accelerate the global diffusion of mitigation technologies, practices and policies
    and align these with other development objectives. Choice architecture can help
    end-users adopt technology and low-GHG-intensive options. Adoption of low-emission
    technologies lags in most developing countries, particularly least developed ones,
    due in part to weaker enabling conditions, including limited finance, technology
    development and transfer, and capacity building.  International cooperation on
    innovation works best when tailored to and beneficial for local value chains,
    when partners collaborate on an equal footing, and when capacity building is an
    integral part of the effort.  Technological innovation can have trade-offs that
    include externalities such as new and greater environmental impacts and social
    inequalities; rebound effects leading to lower net emission reductions or even
    emission increases; and overdependence on foreign knowledge and providers. Appropriately
    designed policies and governance have helped address distributional impacts and
    rebound effects. For example, digital technologies can promote large increases
    in energy efficiency through coordination and an economic shift to services. However,
    societal digitalization can induce greater consumption of goods and energy and
    increased electronic waste as well as negatively impacting labour markets and
    worsening inequalities between and within countries. Digitalisation requires appropriate
    governance and policies in order to enhance mitigation potential. Effective policy
    packages can help to realise synergies, avoid trade-offs and/or reduce rebound
    effects: these might include a mix of efficiency targets, performance standards,
    information provision, carbon pricing, finance and technical assistance .  Technology
    transfer to expand use of digital technologies for land use monitoring, sustainable
    land management, and improved agricultural productivity supports reduced emissions
    from deforestation and land use change while also improving GHG accounting and
    standardisation .'
paragraph_topics:
  A.1.1: Observed Warming and its Causes
  A.1.3: Observed Warming and its Causes
  A.1.5: Observed Warming and its Causes
  A.2.1: Observed Changes and Impacts
  A.2.2: Observed Changes and Impacts
  A.2.3: Observed Changes and Impacts
  A.2.4: Observed Changes and Impacts
  A.2.5: Observed Changes and Impacts
  A.2.6: Observed Changes and Impacts
  A.2.7: Observed Changes and Impacts
  A.3.1: Current Progress in Adaptation and Gaps and Challenges
  A.3.2: Current Progress in Adaptation and Gaps and Challenges
  A.3.3: Current Progress in Adaptation and Gaps and Challenges
  A.3.6: Current Progress in Adaptation and Gaps and Challenges
  A.4.1: Current Mitigation Progress, Gaps and Challenges
  A.4.2: Current Mitigation Progress, Gaps and Challenges
  A.4.3: Current Mitigation Progress, Gaps and Challenges
  A.4.4: Current Mitigation Progress, Gaps and Challenges
  A.4.5: Current Mitigation Progress, Gaps and Challenges
  B.1.1: Future Climate Change
  B.1.4: Future Climate Change
  B.1.5: Future Climate Change
  B.2.1: Climate Change Impacts and Climate-Related Risks
  B.2.2: Climate Change Impacts and Climate-Related Risks
  B.3.1: Likelihood and Risks of Unavoidable, Irreversible or Abrupt Changes
  B.3.2: Likelihood and Risks of Unavoidable, Irreversible or Abrupt Changes
  B.4.1: Adaptation Options and their Limits in a Warmer World
  B.4.2: Adaptation Options and their Limits in a Warmer World
  B.4.3: Adaptation Options and their Limits in a Warmer World
  B.5.1: Carbon Budgets and Net Zero Emissions
  B.5.3: Carbon Budgets and Net Zero Emissions
  B.6.1: Mitigation Pathways
  B.6.2: Mitigation Pathways
  B.6.3: Mitigation Pathways
  B.6.4: Mitigation Pathways
  B.7.1: 'Overshoot: Exceeding a Warming Level and Returning'
  B.7.2: 'Overshoot: Exceeding a Warming Level and Returning'
  B.7.3: 'Overshoot: Exceeding a Warming Level and Returning'
  C.1.1: Urgency of Near-Term Integrated Climate Action
  C.1.2: Urgency of Near-Term Integrated Climate Action
  C.1.3: Urgency of Near-Term Integrated Climate Action
  C.2.1: The Benefits of Near-Term Action
  C.2.2: The Benefits of Near-Term Action
  C.2.3: The Benefits of Near-Term Action
  C.2.4: The Benefits of Near-Term Action
  C.2.5: The Benefits of Near-Term Action
  C.3.1: Mitigation and Adaptation Options across Systems
  C.3.2: Mitigation and Adaptation Options across Systems
  C.3.3: Mitigation and Adaptation Options across Systems
  C.3.4: Mitigation and Adaptation Options across Systems
  C.3.5: Mitigation and Adaptation Options across Systems
  C.3.6: Mitigation and Adaptation Options across Systems
  C.3.7: Mitigation and Adaptation Options across Systems
  C.3.8: Mitigation and Adaptation Options across Systems
  C.4.1: Synergies and Trade-Offs with Sustainable Development
  C.4.2: Synergies and Trade-Offs with Sustainable Development
  C.4.3: Synergies and Trade-Offs with Sustainable Development
  C.5.1: Equity and Inclusion
  C.5.2: Equity and Inclusion
  C.5.3: Equity and Inclusion
  C.5.4: Equity and Inclusion
  C.6.1: Governance and Policies
  C.6.2: Governance and Policies
  C.6.3: Governance and Policies
  C.6.4: Governance and Policies
  C.6.5: Governance and Policies
  C.7.1: Finance, Technology and International Cooperation
  C.7.3: Finance, Technology and International Cooperation
  C.7.4: Finance, Technology and International Cooperation
  C.7.5: Finance, Technology and International Cooperation
pointers:
  A.1.1:
  - 2.1.1
  A.1.3:
  - 2.1.1
  A.1.5:
  - 2.1.1
  A.2.1:
  - 2.1.2
  A.2.2:
  - 2.1.2
  - '4.4'
  A.2.3:
  - 2.1.2
  A.2.4:
  - 2.1.2
  A.2.5:
  - 2.1.2
  A.2.6:
  - 2.1.2
  A.2.7:
  - 2.1.2
  A.3.1:
  - 2.2.3
  A.3.2:
  - 2.2.3
  A.3.3:
  - 2.3.2
  A.3.6:
  - 2.3.2
  - 2.3.3
  A.4.1:
  - 2.2.1
  - 2.2.2
  A.4.2:
  - 2.2.2
  A.4.3:
  - 2.3.1
  - '4.1'
  A.4.4:
  - 2.2.2
  - 2.3.1
  - 3.1.1
  A.4.5:
  - 2.2.2
  - 2.3.1
  - 2.3.3
  B.1.1:
  - 3.1.1
  - 3.3.4
  - '4.3'
  B.1.4:
  - 3.1.1
  - 3.1.3
  B.1.5:
  - '4.3'
  B.2.1:
  - '4.3'
  B.2.2:
  - 3.1.2
  - 3.1.3
  B.3.1:
  - 3.1.3
  B.3.2:
  - 3.1.2
  - 3.1.3
  B.4.1:
  - '3.2'
  - '4.1'
  - '4.2'
  B.4.2:
  - 2.3.2
  - '3.2'
  - '4.3'
  B.4.3:
  - 2.3.2
  - '3.2'
  B.5.1:
  - 3.1.1
  - 3.3.1
  - 3.3.2
  - 3.3.3
  B.5.3:
  - 2.3.1
  - 3.3.1
  B.6.1:
  - 3.3.2
  - 3.3.4
  - '4.1'
  B.6.2:
  - 3.3.2
  - 3.3.3
  B.6.3:
  - 3.3.3
  - '4.1'
  - '4.5'
  B.6.4:
  - 3.4.1
  B.7.1:
  - 3.3.2
  - 3.3.4
  B.7.2:
  - 3.1.2
  - 3.3.4
  B.7.3:
  - 3.3.3
  - 3.3.4
  - 3.4.1
  C.1.1:
  - '3.4'
  - 3.4.2
  - '4.1'
  C.1.2:
  - '3.4'
  - '4.2'
  - '4.4'
  - '4.5'
  - '4.7'
  - '4.8'
  C.1.3:
  - 3.1.3
  - 3.3.3
  - 3.4.1
  - '4.1'
  - '4.2'
  - '4.3'
  - '4.4'
  C.2.1:
  - '4.1'
  - '4.2'
  - '4.3'
  C.2.2:
  - 2.1.2
  - 3.1.2
  - '3.2'
  - 3.3.1
  - 3.3.3
  - '4.1'
  - '4.2'
  - '4.3'
  C.2.3:
  - '4.2'
  - 4.5.4
  - 4.5.5
  - '4.6'
  C.2.4:
  - 3.4.1
  - '4.2'
  C.2.5:
  - '4.2'
  - '4.4'
  - '4.7'
  - 4.8.1
  C.3.1:
  - '4.1'
  - 4.5.1
  - 4.5.6
  - 4.5.2
  - 4.5.3
  - 4.5.4
  - 4.5.5
  C.3.2:
  - 4.5.1
  C.3.3:
  - 4.5.2
  - 4.5.3
  C.3.4:
  - 4.5.3
  C.3.5:
  - 4.5.4
  C.3.6:
  - 4.5.4
  - '4.6'
  C.3.7:
  - 4.5.5
  C.3.8:
  - 4.5.6
  C.4.1:
  - '4.4'
  - '4.6'
  C.4.2:
  - 3.4.1
  - '4.6'
  - '4.9'
  C.4.3:
  - '4.2'
  - 4.5.3
  - 4.5.5
  - '4.6'
  - '4.9'
  C.5.1:
  - '4.4'
  C.5.2:
  - '4.4'
  C.5.3:
  - '4.4'
  - 4.5.3
  - 4.5.5
  - 4.5.6
  C.5.4:
  - '2.1'
  - '4.4'
  C.6.1:
  - 2.2.2
  - '4.7'
  C.6.2:
  - '2.2'
  - '4.7'
  C.6.3:
  - '4.4'
  - '4.7'
  C.6.4:
  - 2.2.2
  - '4.7'
  C.6.5:
  - '4.4'
  - 4.5.6
  - '4.7'
  C.7.1:
  - 4.8.1
  C.7.3:
  - 4.8.1
  C.7.4:
  - 4.8.1
  C.7.5:
  - 4.8.3
section_topics:
  A.1.1: Current Status and Trends
  A.1.3: Current Status and Trends
  A.1.5: Current Status and Trends
  A.2.1: Current Status and Trends
  A.2.2: Current Status and Trends
  A.2.3: Current Status and Trends
  A.2.4: Current Status and Trends
  A.2.5: Current Status and Trends
  A.2.6: Current Status and Trends
  A.2.7: Current Status and Trends
  A.3.1: Current Status and Trends
  A.3.2: Current Status and Trends
  A.3.3: Current Status and Trends
  A.3.6: Current Status and Trends
  A.4.1: Current Status and Trends
  A.4.2: Current Status and Trends
  A.4.3: Current Status and Trends
  A.4.4: Current Status and Trends
  A.4.5: Current Status and Trends
  B.1.1: Future Climate Change, Risks, and Long-Term Responses
  B.1.4: Future Climate Change, Risks, and Long-Term Responses
  B.1.5: Future Climate Change, Risks, and Long-Term Responses
  B.2.1: Future Climate Change, Risks, and Long-Term Responses
  B.2.2: Future Climate Change, Risks, and Long-Term Responses
  B.3.1: Future Climate Change, Risks, and Long-Term Responses
  B.3.2: Future Climate Change, Risks, and Long-Term Responses
  B.4.1: Future Climate Change, Risks, and Long-Term Responses
  B.4.2: Future Climate Change, Risks, and Long-Term Responses
  B.4.3: Future Climate Change, Risks, and Long-Term Responses
  B.5.1: Future Climate Change, Risks, and Long-Term Responses
  B.5.3: Future Climate Change, Risks, and Long-Term Responses
  B.6.1: Future Climate Change, Risks, and Long-Term Responses
  B.6.2: Future Climate Change, Risks, and Long-Term Responses
  B.6.3: Future Climate Change, Risks, and Long-Term Responses
  B.6.4: Future Climate Change, Risks, and Long-Term Responses
  B.7.1: Future Climate Change, Risks, and Long-Term Responses
  B.7.2: Future Climate Change, Risks, and Long-Term Responses
  B.7.3: Future Climate Change, Risks, and Long-Term Responses
  C.1.1: Responses in the Near Term
  C.1.2: Responses in the Near Term
  C.1.3: Responses in the Near Term
  C.2.1: Responses in the Near Term
  C.2.2: Responses in the Near Term
  C.2.3: Responses in the Near Term
  C.2.4: Responses in the Near Term
  C.2.5: Responses in the Near Term
  C.3.1: Responses in the Near Term
  C.3.2: Responses in the Near Term
  C.3.3: Responses in the Near Term
  C.3.4: Responses in the Near Term
  C.3.5: Responses in the Near Term
  C.3.6: Responses in the Near Term
  C.3.7: Responses in the Near Term
  C.3.8: Responses in the Near Term
  C.4.1: Responses in the Near Term
  C.4.2: Responses in the Near Term
  C.4.3: Responses in the Near Term
  C.5.1: Responses in the Near Term
  C.5.2: Responses in the Near Term
  C.5.3: Responses in the Near Term
  C.5.4: Responses in the Near Term
  C.6.1: Responses in the Near Term
  C.6.2: Responses in the Near Term
  C.6.3: Responses in the Near Term
  C.6.4: Responses in the Near Term
  C.6.5: Responses in the Near Term
  C.7.1: Responses in the Near Term
  C.7.3: Responses in the Near Term
  C.7.4: Responses in the Near Term
  C.7.5: Responses in the Near Term
summaries:
  A.1.1: Global surface temperature was 1.09 [0.95 to 1.20]°C5 higher in 2011–2020
    than 1850–19006, with larger increases  over land than over the ocean. Global
    surface temperature in the first two decades of the 21st century was 0.99 [0.84
    to 1.10]°C higher than 1850–1900. Global surface temperature has increased faster
    since 1970 than in any other 50-year period over at least the last 2000 years.
    The likely range of total human-caused global surface temperature increase from
    1850–1900 to 2010–20197 is 0.8°C to  1.3°C, with a best estimate of 1.07°C. Over
    this period, it is likely that well-mixed greenhouse gases contributed a warming
    of 1.0°C to 2.0°C8, and other human drivers contributed a cooling of 0.0°C to
    0.8°C, natural drivers changed global surface temperature by –0.1°C to +0.1°C,
    and internal variability changed it by –0.2°C to +0.2°C.
  A.1.3: Observed increases in well-mixed GHG concentrations since around 1750 are
    unequivocally caused by GHG emissions  from human activities over this period.
    Historical cumulative net CO2 emissions from 1850 to 2019 were 2400 ± 240 GtCO2
    of which more than half occurred between 1850 and 1989, and about 42% occurred
    between 1990 and 2019 . In 2019, atmospheric CO2 concentrations were higher than
    at any time in at least 2 million years, and concentrations of methane and nitrous
    oxide  were higher than at any time in at least 800, years. Global net anthropogenic
    GHG emissions have been estimated to be 59 ± 6.6 GtCO2-eq9 in 2019, about 12%   higher
    than in 2010 and 54% higher than in 1990, with the largest share and growth in
    gross GHG emissions occurring in CO2 from fossil fuels combustion and industrial
    processes followed by methane, whereas the highest relative growth occurred in
    fluorinated gases, starting from low levels in 1990. Average annual GHG emissions
    during 2010–2019 were higher than in any previous decade on record, while the
    rate of growth between 2010 and 2019 was lower than that between 2000 and 2009.
    In 2019, approximately 79% of global GHG emissions came from the sectors of energy,
    industry, transport, and buildings together and 22%10 from agriculture, forestry
    and other land use. Emissions reductions in CO2-FFI due to improvements in energy
    intensity of GDP and carbon intensity of energy, have been less than emissions
    increases from rising global activity levels in industry, energy supply, transport,
    agriculture and buildings.
  A.1.5: Historical contributions of CO2 emissions vary substantially across regions
    in terms of total magnitude, but also in  terms of contributions to CO2-FFI and
    net CO2 emissions from land use, land-use change and forestry. In 2019, around
    35% of the global population live in countries emitting more than 9 tCO2-eq per
    capita  while 41% live in countries emitting less than 3 tCO2-eq per capita; of
    the latter a substantial share lacks access to modern energy services. Least Developed
    Countries and Small Island Developing States have much lower per capita emissions
    than the global average, excluding CO2-LULUCF. The 10% of households with the
    highest per capita emissions contribute 34–45% of global consumption-based household
    GHG emissions, while the bottom 50% contribute 13–15%.
  A.2.1: It is unequivocal that human influence has warmed the atmosphere, ocean and
    land. Global mean sea level increased by  0.20 [0.15 to 0.25] m between 1901 and
    2018. The average rate of sea level rise was 1.3 [0.6 to 2.1] mm yr-1 between
    1901 and 1971, increasing to 1.9 [0.8 to 2.9] mm yr-1 between 1971 and 2006, and
    further increasing to 3.7 [3.2 to 4.2] mm yr-1 between 2006 and 2018. Human influence
    was very likely the main driver of these increases since at least 1971. Evidence
    of observed changes in extremes such as heatwaves, heavy precipitation, droughts,
    and tropical cyclones, and, in particular, their attribution to human influence,
    has further strengthened since AR5. Human influence has likely increased the chance
    of compound extreme events since the 1950s, including increases in the frequency
    of concurrent heatwaves and droughts.
  A.2.2: Approximately 3.3 to 3.6 billion people live in contexts that are highly
    vulnerable to climate change. Human and  ecosystem vulnerability are interdependent.
    Regions and people with considerable development constraints have high vulnerability
    to climatic hazards. Increasing weather and climate extreme events have exposed
    millions of people to acute food insecurity and reduced water security, with the
    largest adverse impacts observed in many locations and/or communities in Africa,
    Asia, Central and South America, LDCs, Small Islands and the Arctic, and globally
    for Indigenous Peoples, small-scale food producers and low-income households.
    Between 2010 and 2020, human mortality from floods, droughts and storms was 15
    times higher in highly vulnerable regions, compared to regions with very low vulnerability.
  A.2.3: Climate change has caused substantial damages, and increasingly irreversible
    losses, in terrestrial, freshwater,  cryospheric, and coastal and open ocean ecosystems.
    Hundreds of local losses of species have been driven by increases in the magnitude
    of heat extremes with mass mortality events recorded on land and in the ocean.
    Impacts on some ecosystems are approaching irreversibility such as the impacts
    of hydrological changes resulting from the retreat of glaciers, or the changes
    in some mountain  and Arctic ecosystems driven by permafrost thaw.
  A.2.4: Climate change has reduced food security and affected water security, hindering
    efforts to meet Sustainable  Development Goals. Although overall agricultural
    productivity has increased, climate change has slowed this growth over the past
    50 years globally, with related negative impacts mainly in midand low latitude
    regions but positive impacts in some high latitude regions. Ocean warming and
    ocean acidification have adversely affected food production from fisheries and
    shellfish aquaculture in some oceanic regions. Roughly half of the world’s population
    currently experience severe water scarcity for at least part of the year due to
    a combination of climatic and non-climatic drivers.
  A.2.5: In all regions increases in extreme heat events have resulted in human mortality
    and morbidity .  The occurrence of climate-related food-borne and water-borne
    diseases and the incidence of vector-borne diseases have increased. In assessed
    regions, some mental health challenges are associated with increasing temperatures,
    trauma from extreme events, and loss of livelihoods and culture. Climate and weather
    extremes are increasingly driving displacement in Africa, Asia, North America,
    and Central and South America, with small island states in the Caribbean and South
    Pacific being disproportionately affected relative to their small population size
    .
  A.2.6: Climate change has caused widespread adverse impacts and related losses and
    damages to nature and people that are  unequally distributed across systems, regions
    and sectors. Economic damages from climate change have been detected in climate-exposed
    sectors, such as agriculture, forestry, fishery, energy, and tourism. Individual
    livelihoods have been affected through, for example, destruction of homes and
    infrastructure, and loss of property and income, human health and food security,
    with adverse effects on gender and social equity.
  A.2.7: In urban areas, observed climate change has caused adverse impacts on human
    health, livelihoods and key infrastructure.  Hot extremes have intensified in
    cities. Urban infrastructure, including transportation, water, sanitation and
    energy systems have been compromised by extreme and slow-onset events, with resulting
    economic losses, disruptions of services and negative impacts to well-being. Observed
    adverse impacts are concentrated amongst economically and socially marginalised
    urban residents.
  A.3.1: Progress in adaptation planning and implementation has been observed across
    all sectors and regions, generating  multiple benefits. Growing public and political
    awareness of climate impacts and risks has resulted in at least 170 countries
    and many cities including adaptation in their climate policies and planning processes
    .
  A.3.2: 'Effectiveness of adaptation in reducing climate risks16 is documented for
    specific contexts, sectors and regions . Examples of effective adaptation options
    include: cultivar improvements, on-farm water management and storage, soil moisture
    conservation, irrigation, agroforestry, community-based adaptation, farm and landscape
    level diversification in agriculture, sustainable land management approaches,
    use of agroecological principles and practices and other approaches that work
    with natural processes. Ecosystem-based adaptation approaches such as urban greening,
    restoration of wetlands and upstream forest ecosystems have been effective in
    reducing flood risks and urban heat. Combinations of non-structural measures like
    early warning systems and structural measures like levees have reduced loss of
    lives in case of inland flooding. Adaptation options such as disaster risk management,
    early warning systems, climate services and social safety nets have broad applicability
    across multiple sectors.'
  A.3.3: Most observed adaptation responses are fragmented, incremental, sector-specific
    and unequally distributed across  regions. Despite progress, adaptation gaps exist
    across sectors and regions, and will continue to grow under current levels of
    implementation, with the largest adaptation gaps among lower income groups. There
    is increased evidence of maladaptation in various sectors and regions. Maladaptation
    especially affects  marginalised and vulnerable groups adversely. Soft limits
    to adaptation are currently being experienced by small-scale farmers and households
    along some low-  lying coastal areas resulting from financial, governance, institutional
    and policy constraints . Some tropical, coastal, polar and mountain ecosystems
    have reached hard adaptation limits . Adaptation does not prevent all losses and
    damages, even with effective adaptation and before reaching soft and hard limits.
  A.3.6: Key barriers to adaptation are limited resources, lack of private sector
    and citizen engagement, insufficient mobilization  of finance, low climate literacy,
    lack of political commitment, limited research and/or slow and low uptake of adaptation
    science, and low sense of urgency. There are widening disparities between the
    estimated costs of adaptation and the finance allocated to adaptation. Adaptation
    finance has come predominantly from public sources, and a small proportion of
    global tracked climate finance was targeted to adaptation and an overwhelming
    majority to mitigation. Although global tracked climate finance has shown an upward
    trend since AR5, current global financial flows for adaptation, including from
    public and private finance sources, are insufficient and constrain implementation
    of adaptation options, especially in developing countries . Adverse climate impacts
    can reduce the availability of financial resources by incurring losses and damages
    and through impeding national economic growth, thereby further increasing financial
    constraints for adaptation, particularly for developing and least developed countries.
  A.4.1: The UNFCCC, Kyoto Protocol, and the Paris Agreement are supporting rising
    levels of national ambition. The Paris Agreement,  adopted under the UNFCCC, with
    near universal participation, has led to policy development and target-setting
    at national and sub-national levels, in particular in relation to mitigation,
    as well as enhanced transparency of climate action and support. Many regulatory
    and economic instruments have already been deployed successfully . In many countries,
    policies have enhanced energy efficiency, reduced rates of deforestation and accelerated
    technology deployment, leading to avoided and in some cases reduced or removed
    emissions . Multiple lines of evidence suggest that mitigation policies have led
    to several Gt CO2-eq yr-1 of avoided global emissions. At least 18 countries have
    sustained absolute production-based GHG and consumption-based CO2 reductions for
    longer than 10 years. These reductions have only partly offset global emissions
    growth.
  A.4.2: Several mitigation options, notably solar energy, wind energy, electrification
    of urban systems, urban green infrastructure,  energy efficiency, demand-side
    management, improved forest and crop/grassland management, and reduced food waste
    and loss, are technically viable, are becoming increasingly cost effective and
    are generally supported by the public. From 2010 to 2019 there have been sustained
    decreases in the unit costs of solar energy, wind energy , and lithium-ion batteries,
    and large increases in their deployment, e.g., >10× for solar and >100× for electric
    vehicles, varying widely across regions. The mix of policy instruments that reduced
    costs and stimulated adoption includes public R&D, funding for demonstration and
    pilot projects, and demand-pull instruments such as deployment subsidies to attain
    scale. Maintaining emission-intensive systems may, in some regions and sectors,
    be more expensive than transitioning to low emission systems.
  A.4.3: A substantial ‘emissions gap’ exists between global GHG emissions in 2030
    associated with the implementation of  NDCs announced prior to COP2626 and those
    associated with modelled mitigation pathways that limit warming to 1.5°C with
    no or limited overshoot or limit warming to 2°C assuming immediate action. This
    would make it likely that warming will exceed 1.5°C during the 21st century. Global
    modelled mitigation pathways that limit warming to 1.5°C with no or limited overshoot
    or limit warming to 2°C assuming immediate action imply deep global GHG emissions
    reductions this decade 27. Modelled pathways that are consistent with NDCs announced
    prior to COP26 until 2030 and assume no increase in ambition thereafter have higher
    emissions, leading to a median global warming of 2.8 [2.1 to 3.4] °C by 2100 .
    Many countries have signalled an intention to achieve net zero GHG or net zero
    CO2 by around mid-century but pledges differ across countries in terms of scope
    and specificity, and limited policies are to date in place to deliver on them.
  A.4.4: Policy coverage is uneven across sectors . Policies implemented by the end
    of 2020 are projected to  result in higher global GHG emissions in 2030 than emissions
    implied by NDCs, indicating an ‘implementation gap’ . Without a strengthening
    of policies, global warming of 3.2 [2.2 to 3.5] °C is projected by 2100 .
  A.4.5: The adoption of low-emission technologies lags in most developing countries,
    particularly least developed ones, due  in part to limited finance, technology
    development and transfer, and capacity. The magnitude of climate finance flows
    has increased over the last decade and financing channels have broadened but growth
    has slowed since 2018. Financial flows have developed heterogeneously across regions
    and sectors . Public and private finance flows for fossil fuels are still greater
    than those for climate adaptation and mitigation. The overwhelming majority of
    tracked climate finance is directed towards mitigation, but nevertheless falls
    short of the levels needed to limit warming to below 2°C or to 1.5°C across all
    sectors and regions. In 2018, public and publicly mobilised private climate finance
    flows from developed to developing countries were below the collective goal under
    the UNFCCC and Paris Agreement to mobilise USD 100 billion per year by 2020 in
    the context of meaningful mitigation action and transparency on implementation
    .
  B.1.1: Global warming will continue to increase in the near term  mainly due to
    increased cumulative  CO2 emissions in nearly all considered scenarios and modelled
    pathways. In the near term, global warming is more likely than not to reach 1.5°C
    even under the very low GHG emission scenario and likely or very likely to exceed
    1.5°C under higher emissions scenarios. In the considered scenarios and modelled
    pathways, the best estimates of the time when the level of global warming of 1.5°C
    is reached lie in the near term. Global warming declines back to below 1.5°C by
    the end of the 21st century in some scenarios and modelled pathways. The assessed
    climate response to GHG emissions scenarios results in a best estimate of warming
    for 2081–2100 that spans a range from 1.4°C for a very low GHG emissions scenario
    to 2.7°C for an intermediate GHG emissions scenario and 4.4°C for a very high
    GHG emissions scenario 30, with narrower uncertainty ranges than for corresponding
    scenarios in AR5. Discernible differences in trends of global surface temperature
    between contrasting GHG emissions scenarios  would begin to emerge from natural
    variability within around 20 years. Under these contrasting scenarios, discernible
    effects would emerge within years for GHG concentrations, and sooner for air quality
    improvements, due to the combined targeted air pollution controls and strong and
    sustained methane emissions reductions. Targeted reductions of air pollutant emissions
    lead to more rapid improvements in air quality within years compared to reductions
    in GHG emissions only, but in the long term, further improvements are projected
    in scenarios that combine efforts to reduce air pollutants as well as GHG emissions.
    Continued emissions will further affect all major climate system components. With
    every additional increment of global  warming, changes in extremes continue to
    become larger. Continued global warming is projected to further intensify the
    global water cycle, including its variability, global monsoon precipitation, and
    very wet and very dry weather and climate events and seasons. In scenarios with
    increasing CO2 emissions, natural land and ocean carbon sinks are projected to
    take up a decreasing proportion of these emissions. Other projected changes include
    further reduced extents and/or volumes of almost all cryospheric elements, further
    global mean sea level rise, and increased ocean acidification and deoxygenation
    .
  B.1.4: With further warming, every region is projected to increasingly experience
    concurrent and multiple changes in climatic  impact-drivers. Compound heatwaves
    and droughts are projected to become more frequent, including concurrent events
    across multiple locations. Due to relative sea level rise, current 1-in-100 year
    extreme sea level events are projected to occur at least annually in more than
    half of all tide gauge locations by 2100 under all considered scenarios. Other
    projected regional changes include intensification of tropical cyclones and/or
    extratropical storms, and increases in aridity and fire weather.
  B.1.5: Natural variability will continue to modulate human-caused climate changes,
    either attenuating or amplifying projected  changes, with little effect on centennial-scale
    global warming. These modulations are important to consider in adaptation planning,
    especially at the regional scale and in the near term. If a large explosive volcanic
    eruption were to occur, it would temporarily and partially mask human-caused climate
    change by reducing global surface temperature and precipitation for one to three
    years.
  B.2.1: In the near term, every region in the world is projected to face further
    increases in climate hazards , increasing multiple risks to ecosystems and humans
    . Hazards and associated risks expected in the near term include an increase in
    heat-related human mortality and morbidity, food-borne, water-borne, and vector-borne
    diseases, and mental health challenges, flooding in coastal and other low-lying
    cities and regions, biodiversity loss in land, freshwater and ocean ecosystems,
    and a decrease in food production in some regions. Cryosphere-related changes
    in floods, landslides, and water availability have the potential to lead to severe
    consequences for people, infrastructure and the economy in most mountain regions.
    The projected increase in frequency and intensity of heavy precipitation  will
    increase rain-generated local flooding.
  B.2.2: Risks and projected adverse impacts and related losses and damages from climate
    change will escalate with every  increment of global warming. They are higher
    for global warming of 1.5°C than at present, and even higher at 2°C. Compared
    to the AR5, global aggregated risk levels are assessed to become high to very
    high at lower levels of global warming due to recent evidence of observed impacts,
    improved process understanding, and new knowledge on exposure and vulnerability
    of human and natural systems, including limits to adaptation. Due to unavoidable
    sea level rise, risks for coastal ecosystems, people and infrastructure will continue
    to increase beyond 2100. With further warming, climate change risks will become
    increasingly complex and more difficult to manage. Multiple  climatic and non-climatic
    risk drivers will interact, resulting in compounding overall risk and risks cascading
    across sectors and regions. Climate-driven food insecurity and supply instability,
    for example, are projected to increase with increasing global warming, interacting
    with non-climatic risk drivers such as competition for land between urban expansion
    and food production, pandemics and conflict. For any given warming level, the
    level of risk will also depend on trends in vulnerability and exposure of humans
    and  ecosystems. Future exposure to climatic hazards is increasing globally due
    to socio-economic development trends including migration, growing inequality and
    urbanisation. Human vulnerability will concentrate in informal settlements and
    rapidly growing smaller settlements. In rural areas vulnerability will be heightened
    by high reliance on climatesensitive livelihoods. Vulnerability of ecosystems
    will be strongly influenced by past, present, and future patterns of unsustainable
    consumption and production, increasing demographic pressures, and persistent unsustainable
    use and management of land, ocean, and water. Loss of ecosystems and their services
    has cascading and long-term impacts on people globally, especially for Indigenous
    Peoples and local communities who are directly dependent on ecosystems to meet
    basic needs.
  B.3.1: Limiting global surface temperature does not prevent continued changes in
    climate system components that have  multi-decadal or longer timescales of response.
    Sea level rise is unavoidable for centuries to millennia due to continuing deep
    ocean warming and ice sheet melt, and sea levels will remain elevated for thousands
    of years . However, deep, rapid, and sustained GHG emissions reductions would
    limit further sea level rise acceleration and projected long-term sea level rise
    commitment. Relative to 1995–2014, the likely global mean sea level rise under
    the SSP1-1.9 GHG emissions scenario is 0.15–0.23 m by 2050 and 0.28–0.55 m by
    2100; while for the SSP5-8.5 GHG emissions scenario it is 0.20–0.29 m by 2050
    and 0.63–1.01 m by 2100. Over the next 2000 years, global mean sea level will
    rise by about 2–3 m if warming is limited to 1.5°C and 2–6 m if limited to 2°C.
  B.3.2: The likelihood and impacts of abrupt and/or irreversible changes in the climate
    system, including changes triggered  when tipping points are reached, increase
    with further global warming. As warming levels increase, so do the risks of species
    extinction or irreversible loss of biodiversity in ecosystems including forests,
    coral reefs and in Arctic regions. At sustained warming levels between 2°C and
    3°C, the Greenland and West Antarctic ice sheets will be lost almost completely
    and irreversibly over multiple millennia, causing several metres of sea level
    rise. The probability and rate of ice mass loss increase with higher global surface
    temperatures. The probability of low-likelihood outcomes associated with potentially
    very large impacts increases with higher global  warming levels. Due to deep uncertainty
    linked to ice-sheet processes, global mean sea level rise above the likely range
    – approaching 2 m by 2100 and in excess of 15 m by 2300 under the very high GHG
    emissions scenario  – cannot be excluded. There is medium confidence that the
    Atlantic Meridional Overturning Circulation will not collapse abruptly before
    2100, but if it were to occur, it would very likely cause abrupt shifts in regional
    weather patterns, and large impacts on ecosystems and human activities.
  B.4.1: The effectiveness of adaptation, including ecosystem-based and most water-related
    options, will decrease with  increasing warming. The feasibility and effectiveness
    of options increase with integrated, multi-sectoral solutions that differentiate
    responses based on climate risk, cut across systems and address social inequities.
    As adaptation options often have long implementation times, long-term planning
    increases their efficiency.
  B.4.2: With additional global warming, limits to adaptation and losses and damages,
    strongly concentrated among vulnerable  populations, will become increasingly
    difficult to avoid. Above 1.5°C of global warming, limited freshwater resources
    pose potential hard adaptation limits for small islands and for regions dependent
    on glacier and snow melt. Above that level, ecosystems such as some warm-water
    coral reefs, coastal wetlands, rainforests, and polar and mountain ecosystems
    will have reached or surpassed hard adaptation limits and as a consequence, some
    Ecosystem-based Adaptation measures will also lose their effectiveness.
  B.4.3: Actions that focus on sectors and risks in isolation and on short-term gains
    often lead to maladaptation over the long  term, creating lock-ins of vulnerability,
    exposure and risks that are difficult to change. For example, seawalls effectively
    reduce impacts to people and assets in the short term but can also result in lock-ins
    and increase exposure to climate risks in the long term unless they are integrated
    into a long-term adaptive plan. Maladaptive responses can worsen existing inequities
    especially for Indigenous Peoples and marginalised groups and decrease ecosystem
    and biodiversity resilience. Maladaptation can be avoided by flexible, multi-sectoral,
    inclusive, long-term planning and implementation of adaptation actions, with co-benefits
    to many sectors and systems.
  B.5.1: From a physical science perspective, limiting human-caused global warming
    to a specific level requires limiting cumulative  CO2 emissions, reaching at least
    net zero CO2 emissions, along with strong reductions in other greenhouse gas emissions.
    Reaching net zero GHG emissions primarily requires deep reductions in CO2, methane,
    and other GHG emissions, and implies net negative CO2 emissions. Carbon dioxide
    removal will be necessary to achieve net negative CO2 emissions. Net zero GHG
    emissions, if sustained, are projected to result in a gradual decline in global
    surface temperatures after an earlier peak. For every 1000 GtCO2 emitted by human
    activity, global surface temperature rises by 0.45°C . The best estimates of the
    remaining carbon budgets from the beginning of 2020 are 500 GtCO2 for a 50% likelihood
    of limiting global warming to 1.5°C and 1150 GtCO2 for a 67% likelihood of limiting
    warming to 2°C40. The stronger the reductions in non-CO2 emissions, the lower
    the resulting temperatures are for a given remaining carbon budget or the larger
    remaining carbon budget for the same level of temperature change.
  B.5.3: If the annual CO2 emissions between 2020–2030 stayed, on average, at the
    same level as 2019, the resulting cumulative  emissions would almost exhaust the
    remaining carbon budget for 1.5°C, and deplete more than a third of the remaining
    carbon budget for 2°C. Estimates of future CO2 emissions from existing fossil
    fuel infrastructures without additional abatement already exceed the remaining
    carbon budget for limiting warming to 1.5°C . Projected cumulative future CO2
    emissions over the lifetime of existing and planned fossil fuel infrastructure,
    if historical operating patterns are maintained and without additional abatement,
    are approximately equal to the remaining carbon budget for limiting warming to
    2°C with a likelihood of 83%44.
  B.6.1: 'Global modelled pathways provide information on limiting warming to different
    levels; these pathways, particularly  their sectoral and regional aspects, depend
    on the assumptions described in Box SPM.1. Global modelled pathways that limit
    warming to 1.5°C with no or limited overshoot or limit warming to 2°C are characterized
    by deep, rapid, and, in most cases, immediate GHG emissions reductions. Pathways
    that limit warming to 1.5 °C with no or limited overshoot reach net zero CO2 in
    the early 2050s, followed by net negative CO2 emissions. Those pathways that reach
    net zero GHG emissions do so around the 2070s. Pathways that limit warming to
    2 °C reach net zero CO2 emissions in the early 2070s. Global GHG emissions are
    projected to peak between 2020 and at the latest before 2025 in global modelled
    pathways that limit warming to 1.5°C with no or limited overshoot and in those
    that limit warming to 2°C and assume immediate action.  '
  B.6.2: Reaching net zero CO2 or GHG emissions primarily requires deep and rapid
    reductions in gross emissions of CO2, as  well as substantial reductions of non-CO2
    GHG emissions. For example, in modelled pathways that limit warming to 1.5°C with
    no or limited overshoot, global methane emissions are reduced by 34 [21–57] %
    by 2030 relative to 2019. However, some hard-to-abate residual GHG emissions  remain
    and would need to be counterbalanced by deployment of CDR methods to achieve net
    zero CO2 or GHG emissions. As a result, net zero CO2 is reached earlier than net
    zero GHGs.
  B.6.3: Global modelled mitigation pathways reaching net zero CO2 and GHG emissions
    include transitioning from fossil fuels  without carbon capture and storage to
    very low- or zero-carbon energy sources, such as renewables or fossil fuels with
    CCS, demand-side measures and improving efficiency, reducing non-CO2 GHG emissions,
    and CDR47. In most global modelled pathways, land-use change and forestry and
    the energy supply sector reach net zero CO2 emissions earlier than the buildings,
    industry and transport sectors.
  B.6.4: Mitigation options often have synergies with other aspects of sustainable
    development, but some options can also  have trade-offs. There are potential synergies
    between sustainable development and, for instance, energy efficiency and renewable
    energy. Similarly, depending on the context, biological CDR methods like reforestation,
    improved forest management, soil carbon sequestration, peatland restoration and
    coastal blue carbon management can enhance biodiversity and ecosystem functions,
    employment and local livelihoods. However, afforestation or production of biomass
    crops can have adverse socio-economic and environmental impacts, including on
    biodiversity, food and water security, local livelihoods and the rights of Indigenous
    Peoples, especially if implemented at large scales and where land tenure is insecure.
    Modelled pathways that assume using resources more efficiently or that shift global
    development towards sustainability include fewer challenges, such as less dependence
    on CDR and pressure on land and biodiversity.
  B.7.1: Only a small number of the most ambitious global modelled pathways limit
    global warming to 1.5°C  by 2100  without exceeding this level temporarily. Achieving
    and sustaining net negative global CO2 emissions, with annual rates of CDR greater
    than residual CO2 emissions, would gradually reduce the warming level again. Adverse
    impacts that occur during this period of overshoot and cause additional warming
    via feedback mechanisms, such as increased wildfires, mass mortality of trees,
    drying of peatlands, and permafrost thawing, weakening natural land carbon sinks
    and increasing releases of GHGs would make the return more challenging.
  B.7.2: The higher the magnitude and the longer the duration of overshoot, the more
    ecosystems and societies are exposed  to greater and more widespread changes in
    climatic impact-drivers, increasing risks for many natural and human systems.
    Compared to pathways without overshoot, societies would face higher risks to infrastructure,
    low-lying coastal settlements, and associated livelihoods. Overshooting 1.5°C
    will result in irreversible adverse impacts on certain ecosystems with low resilience,
    such as polar, mountain, and coastal ecosystems, impacted by ice-sheet melt, glacier
    melt, or by accelerating and higher committed sea level rise.
  B.7.3: 'The larger the overshoot, the more net negative CO2 emissions would be needed
    to return to 1.5°C by 2100. Transitioning  towards net zero CO2 emissions faster
    and reducing non-CO2 emissions such as methane more rapidly would limit peak warming
    levels and reduce the requirement for net negative CO2 emissions, thereby reducing
    feasibility and sustainability concerns, and social and environmental risks associated
    with CDR deployment at large scales. '
  C.1.1: Evidence of observed adverse impacts and related losses and damages, projected
    risks, levels and trends in vulnerability  and adaptation limits, demonstrate
    that worldwide climate resilient development action is more urgent than previously
    assessed in AR5. Climate resilient development integrates adaptation and GHG mitigation
    to advance sustainable development for all. Climate resilient development pathways
    have been constrained by past development, emissions and climate change and are
    progressively constrained by every increment of warming, in particular beyond
    1.5°C.
  C.1.2: 'Government actions at sub-national, national and international levels, with
    civil society and the private sector, play a  crucial role in enabling and accelerating
    shifts in development pathways towards sustainability and climate resilient development.
    Climate resilient development is enabled when governments, civil society and the
    private sector make inclusive development choices that prioritize risk reduction,
    equity and justice, and when decision-making processes, finance and actions are
    integrated across governance levels, sectors, and timeframes . Enabling conditions
    are differentiated by national, regional and local circumstances and geographies,
    according to capabilities, and include: political commitment and follow-through,
    coordinated policies, social and international cooperation, ecosystem stewardship,
    inclusive governance, knowledge diversity, technological innovation, monitoring
    and evaluation, and improved access to adequate financial resources, especially
    for vulnerable regions, sectors and communities.'
  C.1.3: Continued emissions will further affect all major climate system components,
    and many changes will be irreversible on  centennial to millennial time scales
    and become larger with increasing global warming. Without urgent, effective, and
    equitable mitigation and adaptation actions, climate change increasingly threatens
    ecosystems, biodiversity, and the livelihoods, health and well-being of current
    and future generations.
  C.2.1: Deep, rapid, and sustained mitigation and accelerated implementation of adaptation
    actions in this decade would  reduce future losses and damages related to climate
    change for humans and ecosystems. As adaptation options often have long implementation
    times, accelerated implementation of adaptation in this decade is important to
    close adaptation gaps. Comprehensive, effective, and innovative responses integrating
    adaptation and mitigation can harness synergies and reduce trade-offs between
    adaptation and mitigation .
  C.2.2: Delayed mitigation action will further increase global warming and losses
    and damages will rise and additional human  and natural systems will reach adaptation
    limits. Challenges from delayed adaptation and mitigation actions include the
    risk of cost escalation, lock-in of infrastructure, stranded assets, and reduced
    feasibility and effectiveness of adaptation and mitigation options. Without rapid,
    deep and sustained mitigation and accelerated adaptation actions, losses and damages
    will continue to increase, including projected adverse impacts in Africa, LDCs,
    SIDS, Central and South America, Asia and the Arctic, and will disproportionately
    affect the most vulnerable populations.
  C.2.3: Accelerated climate action can also provide co-benefits  . Many mitigation
    actions would  have benefits for health through lower air pollution, active mobility,
    and shifts to sustainable healthy diets. Strong, rapid and sustained reductions
    in methane emissions can limit near-term warming and improve air quality by reducing
    global surface ozone. Adaptation can generate multiple additional benefits such
    as improving agricultural productivity, innovation, health and well-being, food
    security, livelihood, and biodiversity conservation.
  C.2.4: Cost-benefit analysis remains limited in its ability to represent all avoided
    damages from climate change . The economic benefits for human health from air
    quality improvement arising from mitigation action can be of the same order of
    magnitude as mitigation costs, and potentially even larger. Even without accounting
    for all the benefits of avoiding potential damages, the global economic and social
    benefit of limiting global warming to 2°C exceeds the cost of mitigation in most
    of the assessed literature 50. More rapid climate change mitigation, with emissions
    peaking earlier, increases co-benefits and reduces feasibility risks and costs
    in the long-term, but requires higher up-front investments.
  C.2.5: Ambitious mitigation pathways imply large and sometimes disruptive changes
    in existing economic structures, with  significant distributional consequences
    within and between countries. To accelerate climate action, the adverse consequences
    of these changes can be moderated by fiscal, financial, institutional and regulatory
    reforms and by integrating climate actions with macroeconomic policies through
    economy-wide packages, consistent with national circumstances, supporting sustainable
    low-emission growth paths; climate resilient safety nets and social protection;
    and improved access to finance for low-emissions infrastructure and technologies,
    especially in developing countries.
  C.3.1: 'The systemic change required to achieve rapid and deep emissions reductions
    and transformative adaptation to climate  change is unprecedented in terms of
    scale, but not necessarily in terms of speed. Systems transitions include: deployment
    of low- or zero-emission technologies; reducing and changing demand through infrastructure
    design and access, socio-cultural and behavioural changes, and increased technological
    efficiency and adoption; social protection, climate services or other services;
    and protecting and restoring ecosystems. Feasible, effective, and low-cost options
    for mitigation and adaptation are already available. The availability, feasibility
    and potential of mitigation and adaptation options in the near term differs across
    systems and regions .'
  C.3.2: 'Net zero CO2 energy systems entail: a substantial reduction in overall fossil
    fuel use, minimal use of unabated fossil  fuels, and use of carbon capture and
    storage in the remaining fossil fuel systems; electricity systems that emit no
    net CO2; widespread electrification; alternative energy carriers in applications
    less amenable to electrification; energy conservation and efficiency; and greater
    integration across the energy system. Large contributions to emissions reductions
    with costs less than USD 20 tCO2-eq-1 come from solar and wind energy, energy
    efficiency improvements, and methane emissions reductions. There are feasible
    adaptation options that support infrastructure resilience, reliable power systems
    and efficient water use for existing and new energy generation systems. Energy
    generation diversification  and demand-side management can increase energy reliability
    and reduce vulnerabilities to climate change. Climate responsive energy markets,
    updated design standards on energy assets according to current and projected climate
    change, smart-grid technologies, robust transmission systems and improved capacity
    to respond to supply deficits have high feasibility in the medium to long term,
    with mitigation co-benefits.'
  C.3.3: Reducing industry GHG emissions entails coordinated action throughout value
    chains to promote all mitigation  options, including demand management, energy
    and materials efficiency, circular material flows, as well as abatement technologies
    and transformational changes in production processes. In transport, sustainable
    biofuels, low-emissions hydrogen, and derivatives can support mitigation of CO2
    emissions from shipping, aviation, and heavy-duty land transport but require production
    process improvements and cost reductions. Sustainable biofuels can offer additional
    mitigation benefits in land-based transport in the short and medium term. Electric
    vehicles powered by low-GHG emissions electricity have large potential to reduce
    land-based transport GHG emissions, on a life cycle basis. Advances in battery
    technologies could facilitate the electrification of heavy-duty trucks and compliment
    conventional electric rail systems. The environmental footprint of battery production
    and growing concerns about critical minerals can be addressed by material and
    supply diversification strategies, energy and material efficiency improvements,
    and circular material flows.
  C.3.4: Urban systems are critical for achieving deep emissions reductions and advancing
    climate resilient development . Key adaptation and mitigation elements in cities
    include considering climate change impacts and risks in the design and planning
    of settlements and infrastructure; land use planning to achieve compact urban
    form, co-location of jobs and housing; supporting public transport and active
    mobility ; the efficient design, construction, retrofit, and use of buildings;
    reducing and changing energy and material consumption; sufficiency; material substitution;
    and electrification in combination with low emissions sources. Urban transitions
    that offer benefits for mitigation, adaptation, human health and wellbeing, ecosystem
    services, and vulnerability reduction for low-income communities are fostered
    by inclusive long-term planning that takes an integrated approach to physical,
    natural and social infrastructure. Green/ natural and blue infrastructure supports
    carbon uptake and storage and either singly or when combined with grey infrastructure
    can reduce energy use and risk from extreme events such as heatwaves, flooding,
    heavy precipitation and droughts, while generating co-benefits for health, well-being
    and livelihoods.
  C.3.5: Many agriculture, forestry, and other land use  options provide adaptation
    and mitigation benefits that could  be upscaled in the near term across most regions.
    Conservation, improved management, and restoration of forests and other ecosystems
    offer the largest share of economic mitigation potential, with reduced deforestation
    in tropical regions having the highest total mitigation potential. Ecosystem restoration,
    reforestation, and afforestation can lead to trade-offs due to competing demands
    on land. Minimizing trade-offs requires integrated approaches to meet multiple
    objectives including food security. Demand-side measures  and sustainable agricultural
    intensification can reduce ecosystem conversion, and methane and nitrous oxide
    emissions, and free up land for reforestation and ecosystem restoration. Sustainably
    sourced agricultural and forest products, including long-lived wood products,
    can be used instead of more GHG-intensive products in other sectors. Effective
    adaptation options include cultivar improvements, agroforestry, community-based
    adaptation, farm and landscape diversification, and urban agriculture. These AFOLU
    response options require integration of biophysical, socioeconomic and other enabling
    factors. Some options, such as conservation of high-carbon ecosystems , deliver
    immediate benefits, while others, such as restoration of high-carbon ecosystems,
    take decades to deliver measurable results.
  C.3.6: Maintaining the resilience of biodiversity and ecosystem services at a global
    scale depends on effective and equitable  conservation of approximately 30% to
    50% of Earth’s land, freshwater and ocean areas, including currently nearnatural
    ecosystems. Conservation, protection and restoration of terrestrial, freshwater,
    coastal and ocean ecosystems, together with targeted management to adapt to unavoidable
    impacts of climate change reduces the vulnerability of biodiversity and ecosystem
    services to climate change, reduces coastal erosion and flooding, and could increase
    carbon uptake and storage if global warming is limited . Rebuilding overexploited
    or depleted fisheries reduces negative climate change impacts on fisheries and
    supports food security, biodiversity, human health and well-being. Land restoration
    contributes to climate change mitigation and adaptation with synergies via enhanced
    ecosystem services and with economically positive returns and co-benefits for
    poverty reduction and improved livelihoods. Cooperation, and inclusive decision
    making, with Indigenous Peoples and local communities, as well as recognition
    of inherent rights of Indigenous Peoples, is integral to successful adaptation
    and mitigation across forests and other ecosystems.
  C.3.7: 'Human health will benefit from integrated mitigation and adaptation options
    that mainstream health into food,  infrastructure, social protection, and water
    policies. Effective adaptation options exist to help protect human health and
    well-being, including: strengthening public health programs related to climate-sensitive
    diseases, increasing health systems resilience, improving ecosystem health, improving
    access to potable water, reducing exposure of water and sanitation systems to
    flooding, improving surveillance and early warning systems, vaccine development,
    improving access to mental healthcare, and Heat Health Action Plans that include
    early warning and response systems. Adaptation strategies which reduce food loss
    and waste or support balanced, sustainable healthy diets contribute to nutrition,
    health, biodiversity and other environmental benefits.'
  C.3.8: Policy mixes that include weather and health insurance, social protection
    and adaptive social safety nets, contingent  finance and reserve funds, and universal
    access to early warning systems combined with effective contingency plans, can
    reduce vulnerability and exposure of human systems. Disaster risk management,
    early warning systems, climate services and risk spreading and sharing approaches
    have broad applicability across sectors. Increasing education including capacity
    building, climate literacy, and information provided through climate services
    and community approaches can facilitate heightened risk perception and accelerate
    behavioural changes and planning.
  C.4.1: Mitigation efforts embedded within the wider development context can increase
    the pace, depth and breadth of emission  reductions. Countries at all stages of
    economic development seek to improve the well-being of people, and their development
    priorities reflect different starting points and contexts. Different contexts
    include but are not limited to social, economic, environmental, cultural, political
    circumstances, resource endowment, capabilities, international environment, and
    prior development. In regions with high dependency on fossil fuels for, among
    other things, revenue and employment generation, mitigating risk for sustainable
    development requires policies that promote economic and energy sector diversification
    and considerations of just transitions principles, processes and practices. Eradicating
    extreme poverty, energy poverty, and providing decent living standards in low-emitting
    countries / regions in the context of achieving sustainable development objectives,
    in the near term, can be achieved without significant global emissions growth.
  C.4.2: Many mitigation and adaptation actions have multiple synergies with Sustainable
    Development Goals  and  sustainable development generally, but some actions can
    also have trade-offs. Potential synergies with SDGs exceed potential trade-offs;
    synergies and trade-offs depend on the pace and magnitude of change and the development
    context including inequalities with consideration of climate justice. Trade-offs
    can be evaluated and minimised by giving emphasis to capacity building, finance,
    governance, technology transfer, investments, development, context specific gender-based
    and other social equity considerations with meaningful participation of Indigenous
    Peoples, local communities and vulnerable populations.
  C.4.3: Implementing both mitigation and adaptation actions together and taking trade-offs
    into account supports co-benefits  and synergies for human health and well-being.
    For example, improved access to clean energy sources and technologies generates
    health benefits especially for women and children; electrification combined with
    low-GHG energy, and shifts to active mobility and public transport can enhance
    air quality, health, employment, and can elicit energy security and deliver equity.
  C.5.1: Equity remains a central element in the UN climate regime, notwithstanding
    shifts in differentiation between states  over time and challenges in assessing
    fair shares. Ambitious mitigation pathways imply large and sometimes disruptive
    changes in economic structure, with significant distributional consequences, within
    and between countries. Distributional consequences within and between countries
    include shifting of income and employment during the transition from high- to
    low-emissions activities.
  C.5.2: Adaptation and mitigation actions that prioritise equity, social justice,
    climate justice, rights-based approaches, and  inclusivity, lead to more sustainable
    outcomes, reduce trade-offs, support transformative change and advance climate
    resilient development. Redistributive policies across sectors and regions that
    shield the poor and vulnerable, social safety nets, equity, inclusion and just
    transitions, at all scales can enable deeper societal ambitions and resolve tradeoffs
    with sustainable development goals. Attention to equity and broad and meaningful
    participation of all relevant actors in decision making at all scales can build
    social trust which builds on equitable sharing of benefits and burdens of mitigation
    that deepen and widen support for transformative changes.
  C.5.3: 'Regions and people  with considerable development constraints have high
    vulnerability to  climatic hazards. Adaptation outcomes for the most vulnerable
    within and across countries and regions are enhanced through approaches focusing
    on equity, inclusivity and rights-based approaches. Vulnerability is exacerbated
    by inequity and marginalisation linked to e.g., gender, ethnicity, low incomes,
    informal settlements, disability, age, and historical and ongoing patterns of
    inequity such as colonialism, especially for many Indigenous Peoples and local
    communities. Integrating climate adaptation into social protection programs, including
    cash transfers and public works programs, is highly feasible and increases resilience
    to climate change, especially when supported by basic services and infrastructure.
    The greatest gains in well-being in urban areas can be achieved by prioritising
    access to finance to reduce climate risk for low-income and marginalised communities
    including people living in informal settlements. '
  C.5.4: The design of regulatory instruments and economic instruments and consumption-based
    approaches, can advance equity.  Individuals with high socio-economic status contribute
    disproportionately to emissions, and have the highest potential for emissions
    reductions. Many options are available for reducing emission-intensive consumption
    while improving societal well-being. Socio-cultural options, behaviour and lifestyle
    changes supported by policies, infrastructure, and technology can help end-users
    shift to low-emissions-intensive consumption, with multiple co-benefits. A substantial
    share of the population in low-emitting countries lack access to modern energy
    services. Technology development, transfer, capacity building and financing can
    support developing countries / regions leapfrogging or transitioning to low-emissions
    transport systems thereby providing multiple co-benefits. Climate resilient development
    is advanced when actors work in equitable, just and inclusive ways to reconcile
    divergent interests, values and worldviews, toward equitable and just outcomes.
  C.6.1: Effective climate governance enables mitigation and adaptation. Effective
    governance provides overall direction on  setting targets and priorities and mainstreaming
    climate action across policy domains and levels, based on national circumstances
    and in the context of international cooperation. It enhances monitoring and evaluation
    and regulatory certainty, prioritising inclusive, transparent and equitable decision-making,
    and improves access to finance and technology.
  C.6.2: Effective local, municipal, national and subnational institutions build consensus
    for climate action among diverse  interests, enable coordination and inform strategy
    setting but require adequate institutional capacity. Policy support is influenced
    by actors in civil society, including businesses, youth, women, labour, media,
    Indigenous Peoples, and local communities. Effectiveness is enhanced by political
    commitment and partnerships between different groups in society.
  C.6.3: 'Effective multilevel governence for mitigation, adaptation, risk management,
    and climate resilient development is  enabled by inclusive decision processes
    that prioritise equity and justice in planning and implementation, allocation
    of appropriate resources, institutional review, and monitoring and evaluation.
    Vulnerabilities and climate risks are often reduced through carefully designed
    and implemented laws, policies, participatory processes, and interventions that
    address context specific inequities such as those based on gender, ethnicity,
    disability, age, location and income. '
  C.6.4: Regulatory and economic instruments could support deep emissions reductions
    if scaled up and applied more widely  . Scaling up and enhancing the use of regulatory
    instruments can improve mitigation outcomes in sectoral applications, consistent
    with national circumstances. Where implemented, carbon pricing instruments have
    incentivized low-cost emissions reduction measures but have been less effective,
    on their own and at prevailing prices during the assessment period, to promote
    higher-cost measures necessary for further reductions . Equity and distributional
    impacts of such carbon pricing instruments, e.g., carbon taxes and emissions trading,
    can be addressed by using revenue to support low-income households, among other
    approaches. Removing fossil fuel subsidies would reduce emissions and yield benefits
    such as improved public revenue, macroeconomic and sustainability performance;
    subsidy removal can have adverse distributional impacts, especially on the most
    economically vulnerable groups which, in some cases can be mitigated by measures
    such as redistributing revenue saved, all of which depend on national circumstances.
    Economy-wide policy packages, such as public spending commitments and pricing
    reforms, can meet short-term economic goals while reducing emissions and shifting
    development pathways towards sustainability. Effective policy packages would be
    comprehensive, consistent, balanced across objectives, and tailored to national
    circumstances.
  C.6.5: Drawing on diverse knowledges and cultural values, meaningful participation
    and inclusive engagement processes—  including Indigenous Knowledge, local knowledge,
    and scientific knowledge—facilitates climate resilient development, builds capacity
    and allows locally appropriate and socially acceptable solutions.
  C.7.1: Improved availability of and access to finance55 would enable accelerated
    climate action .  Addressing needs and gaps and broadening equitable access to
    domestic and international finance, when combined with other supportive actions,
    can act as a catalyst for accelerating adaptation and mitigation, and enabling
    climate resilient development. If climate goals are to be achieved, and to address
    rising risks and accelerate investments in emissions reductions, both adaptation
    and mitigation finance would need to increase many-fold . Increased access to
    finance can build capacity and address soft limits to adaptation and avert rising
    risks, especially for  developing countries, vulnerable groups, regions and sectors.
    Public finance is an important enabler of adaptation and mitigation, and can also
    leverage private finance. Average annual modelled mitigation investment requirements
    for 2020 to 2030 in scenarios that limit warming to 2°C or 1.5°C are a factor
    of three to six greater than current levels, and total mitigation investments
    would need to increase across all sectors and regions. Even if extensive global
    mitigation efforts are implemented, there will be a need for financial, technical,
    and human resources for adaptation.
  C.7.3: 'There is sufficient global capital and liquidity to close global investment
    gaps, given the size of the global financial  system, but there are barriers to
    redirect capital to climate action both within and outside the global financial
    sector and in the context of economic vulnerabilities and indebtedness facing
    developing countries. Reducing financing barriers for scaling up financial flows
    would require clear signalling and support by governments, including a stronger
    alignment of public finances in order to lower real and perceived regulatory,
    cost and market barriers and risks and improving the risk-return profile of investments.
    At the same time, depending on national contexts, financial actors, including
    investors, financial intermediaries, central banks and financial regulators can
    shift the systemic underpricing of climaterelated risks, and reduce sectoral and
    regional mismatches between available capital and investment needs. '
  C.7.4: 'Tracked financial flows fall short of the levels needed for adaptation and
    to achieve mitigation goals across all sectors  and regions. These gaps create
    many opportunities and the challenge of closing gaps is largest in developing
    countries. Accelerated financial support for developing countries from developed
    countries and other sources is a critical enabler to enhance adaptation and mitigation
    actions and address inequities in access to finance, including its costs, terms
    and conditions, and economic vulnerability to climate change for developing countries.
    Scaled-up public grants for mitigation and adaptation funding for vulnerable regions,
    especially in Sub-Saharan Africa, would be cost-effective and have high social
    returns in terms of access to basic energy. Options for scaling up mitigation
    in developing countries include: increased levels of public finance and publicly
    mobilised private finance flows from developed to developing countries in the
    context of the USD 100 billion-a-year goal; increased use of public guarantees
    to reduce risks and leverage private flows at lower cost; local capital markets
    development; and building greater trust in international cooperation processes.
    A coordinated effort to make the post-pandemic recovery sustainable over the longer-term
    can accelerate climate action, including in developing regions and countries facing
    high debt costs, debt distress and macroeconomic uncertainty.'
  C.7.5: 'Enhancing technology innovation systems can provide opportunities to lower
    emissions growth, create social and  environmental co-benefits, and achieve other
    SDGs. Policy packages tailored to national contexts and technological characteristics
    have been effective in supporting low-emission innovation and technology diffusion.
    Public policies can support training and R&D, complemented by both regulatory
    and market-based instruments that create incentives and market opportunities.
    Technological innovation can have trade-offs such as new and greater environmental
    impacts, social inequalities, overdependence on foreign knowledge and providers,
    distributional impacts and rebound effects, requiring appropriate governance and
    policies to enhance potential and reduce trade-offs. Innovation and adoption of
    low-emission technologies lags in most developing countries, particularly least
    developed ones, due in part to weaker enabling conditions, including limited finance,
    technology development and transfer, and capacity building. '
summary_topics:
  A.1.1: Global Surface Temperature
  A.1.3: GHG Emissions
  A.1.5: CO2 Emissions
  A.2.1: Human Influence
  A.2.2: Vulnerability
  A.2.3: Damages
  A.2.4: Food Security
  A.2.5: Mortality and Disease
  A.2.6: Damage Distribution
  A.2.7: Urban Environment
  A.3.1: Progress in Adaptation
  A.3.2: Effectiveness of Adaptation
  A.3.3: Gaps and Limits in Adaptation
  A.3.6: Barriers to Adaptation
  A.4.1: International Agreements
  A.4.2: Mitigation Options
  A.4.3: Emission Gap
  A.4.4: Policy Coverage
  A.4.5: Adoption of Technology
  B.1.1: Global Warming Projections
  B.1.4: Future Effects of Global Warming
  B.1.5: Natural Variability
  B.2.1: Climate Hazards
  B.2.2: Risks and Impact
  B.3.1: Unavoidable Changes
  B.3.2: Likelihood of Unavoidable Changes
  B.4.1: Decrease in Effectiveness of Adaptation
  B.4.2: Limits to Adaptation
  B.4.3: Maladaptation
  B.5.1: Reasons to Limit CO2
  B.5.3: Effects of Not Limiting CO2
  B.6.1: Pathways for Limiting Warming
  B.6.2: Reacing Net Zero Emissions
  B.6.3: Transitioning from Fossil Fuel
  B.6.4: Mitigation Synergies
  B.7.1: Likelihood of Overshoot
  B.7.2: Degree of Overshoot
  B.7.3: Returning after Overshoot
  C.1.1: Urgency of Action
  C.1.2: Insitutional Action
  C.1.3: Risks of Continued Emissions
  C.2.1: Benefits of Adaptation and Mitigation
  C.2.2: Risks of Delayed Mitigation
  C.2.3: Co-Benefits
  C.2.4: Cost-benefit Analysis
  C.2.5: Economic Changes
  C.3.1: Scale of Change Required
  C.3.2: Reaching Net Zero CO2
  C.3.3: Reducing GHG Emissions
  C.3.4: Urban Systems
  C.3.5: Agricolture, Forestry and Land Use
  C.3.6: Conservation of Ecosystems and Biodiversity
  C.3.7: Human Health
  C.3.8: Policies
  C.4.1: Synergies with Different National Contexts
  C.4.2: Synergies with Sustainable Development Goals
  C.4.3: Co-benefits
  C.5.1: Equity
  C.5.2: Sustainable outcomes
  C.5.3: Vulnerable Regions and People
  C.5.4: Regulations
  C.6.1: Governance
  C.6.2: Insitutions
  C.6.3: Decision Processes
  C.6.4: Policy and Economic Instruments
  C.6.5: Diversity and Local Knowledge
  C.7.1: Financing
  C.7.3: Investment Gaps
  C.7.4: Gaps in Financing
  C.7.5: Technological Innovation
titles:
  A.1.1:
  - 'Observed Warming and its Causes

    '
  A.1.3:
  - 'Observed Warming and its Causes

    '
  A.1.5:
  - 'Observed Warming and its Causes

    '
  A.2.1:
  - 'Observed Climate System Changes and Impacts to

    '
  A.2.2:
  - 'Observed Climate System Changes and Impacts to

    '
  - 'Equity and Inclusion in Climate Change Action

    '
  A.2.3:
  - 'Observed Climate System Changes and Impacts to

    '
  A.2.4:
  - 'Observed Climate System Changes and Impacts to

    '
  A.2.5:
  - 'Observed Climate System Changes and Impacts to

    '
  A.2.6:
  - 'Observed Climate System Changes and Impacts to

    '
  A.2.7:
  - 'Observed Climate System Changes and Impacts to

    '
  A.3.1:
  - 'Adaptation Actions to Date

    '
  A.3.2:
  - 'Adaptation Actions to Date

    '
  A.3.3:
  - 'Adaptation Gaps and Barriers

    '
  A.3.6:
  - 'Adaptation Gaps and Barriers

    '
  - 'Lack of Finance as a Barrier to Climate Action

    '
  A.4.1:
  - 'Global Policy Setting

    '
  - 'Mitigation Actions to Date

    '
  A.4.2:
  - 'Mitigation Actions to Date

    '
  A.4.3:
  - 'The Gap Between Mitigation Policies, Pledges and

    '
  - 'The Timing and Urgency of Climate Action

    '
  A.4.4:
  - 'Mitigation Actions to Date

    '
  - 'The Gap Between Mitigation Policies, Pledges and

    '
  - 'Long-term Climate Change

    '
  A.4.5:
  - 'Mitigation Actions to Date

    '
  - 'The Gap Between Mitigation Policies, Pledges and

    '
  - 'Lack of Finance as a Barrier to Climate Action

    '
  B.1.1:
  - 'Long-term Climate Change

    '
  - 'Overshoot Pathways: Increased Risks and Other

    '
  - 'Near-Term Risks

    '
  B.1.4:
  - 'Long-term Climate Change

    '
  - 'The Likelihood and Risks of Abrupt and Irreversible

    '
  B.1.5:
  - 'Near-Term Risks

    '
  B.2.1:
  - 'Near-Term Risks

    '
  B.2.2:
  - 'Impacts and Related Risks

    '
  - 'The Likelihood and Risks of Abrupt and Irreversible

    '
  B.3.1:
  - 'The Likelihood and Risks of Abrupt and Irreversible

    '
  B.3.2:
  - 'Impacts and Related Risks

    '
  - 'The Likelihood and Risks of Abrupt and Irreversible

    '
  B.4.1:
  - 'Long-term Adaptation Options and Limits

    '
  - 'The Timing and Urgency of Climate Action

    '
  - 'Benefits of Strengthening Near-Term Action

    '
  B.4.2:
  - 'Adaptation Gaps and Barriers

    '
  - 'Long-term Adaptation Options and Limits

    '
  - 'Near-Term Risks

    '
  B.4.3:
  - 'Adaptation Gaps and Barriers

    '
  - 'Long-term Adaptation Options and Limits

    '
  B.5.1:
  - 'Long-term Climate Change

    '
  - 'Remaining Carbon Budgets

    '
  - 'Net Zero Emissions: Timing and Implications

    '
  - 'Sectoral Contributions to Mitigation

    '
  B.5.3:
  - 'The Gap Between Mitigation Policies, Pledges and

    '
  - 'Remaining Carbon Budgets

    '
  B.6.1:
  - 'Net Zero Emissions: Timing and Implications

    '
  - 'Overshoot Pathways: Increased Risks and Other

    '
  - 'The Timing and Urgency of Climate Action

    '
  B.6.2:
  - 'Net Zero Emissions: Timing and Implications

    '
  - 'Sectoral Contributions to Mitigation

    '
  B.6.3:
  - 'Sectoral Contributions to Mitigation

    '
  - 'The Timing and Urgency of Climate Action

    '
  - 'Near-Term Mitigation and Adaptation Actions

    '
  B.6.4:
  - 'Synergies and trade-offs, costs and benefits

    '
  B.7.1:
  - 'Net Zero Emissions: Timing and Implications

    '
  - 'Overshoot Pathways: Increased Risks and Other

    '
  B.7.2:
  - 'Impacts and Related Risks

    '
  - 'Overshoot Pathways: Increased Risks and Other

    '
  B.7.3:
  - 'Sectoral Contributions to Mitigation

    '
  - 'Overshoot Pathways: Increased Risks and Other

    '
  - 'Synergies and trade-offs, costs and benefits

    '
  C.1.1:
  - 'Long-Term Interactions Between Adaptation, Mitigation and Sustainable Development

    '
  - 'Advancing Integrated Climate Action for Sustainable

    '
  - 'The Timing and Urgency of Climate Action

    '
  C.1.2:
  - 'Long-Term Interactions Between Adaptation, Mitigation and Sustainable Development

    '
  - 'Benefits of Strengthening Near-Term Action

    '
  - 'Equity and Inclusion in Climate Change Action

    '
  - 'Near-Term Mitigation and Adaptation Actions

    '
  - 'Governance and Policy for Near-Term Climate Change Action

    '
  - 'Strengthening the Response: Finance, International Cooperation and Technology

    '
  C.1.3:
  - 'The Likelihood and Risks of Abrupt and Irreversible

    '
  - 'Sectoral Contributions to Mitigation

    '
  - 'Synergies and trade-offs, costs and benefits

    '
  - 'The Timing and Urgency of Climate Action

    '
  - 'Benefits of Strengthening Near-Term Action

    '
  - 'Near-Term Risks

    '
  - 'Equity and Inclusion in Climate Change Action

    '
  C.2.1:
  - 'The Timing and Urgency of Climate Action

    '
  - 'Benefits of Strengthening Near-Term Action

    '
  - 'Near-Term Risks

    '
  C.2.2:
  - 'Observed Climate System Changes and Impacts to

    '
  - 'Impacts and Related Risks

    '
  - 'Long-term Adaptation Options and Limits

    '
  - 'Remaining Carbon Budgets

    '
  - 'Sectoral Contributions to Mitigation

    '
  - 'The Timing and Urgency of Climate Action

    '
  - 'Benefits of Strengthening Near-Term Action

    '
  - 'Near-Term Risks

    '
  C.2.3:
  - 'Benefits of Strengthening Near-Term Action

    '
  - 'Land, Ocean, Food, and Water

    '
  - 'Health and Nutrition

    '
  - 'Co-Benefits of Adaptation and Mitigation for Sustainable Development Goals

    '
  C.2.4:
  - 'Synergies and trade-offs, costs and benefits

    '
  - 'Benefits of Strengthening Near-Term Action

    '
  C.2.5:
  - 'Benefits of Strengthening Near-Term Action

    '
  - 'Equity and Inclusion in Climate Change Action

    '
  - 'Governance and Policy for Near-Term Climate Change Action

    '
  - 'Finance for Mitigation and Adaptation Actions

    '
  C.3.1:
  - 'The Timing and Urgency of Climate Action

    '
  - 'Energy Systems

    '
  - 'Society, Livelihoods, and Economies

    '
  - 'Industry

    '
  - 'Cities, Settlements and Infrastructure

    '
  - 'Land, Ocean, Food, and Water

    '
  - 'Health and Nutrition

    '
  C.3.2:
  - 'Energy Systems

    '
  C.3.3:
  - 'Industry

    '
  - 'Cities, Settlements and Infrastructure

    '
  C.3.4:
  - 'Cities, Settlements and Infrastructure

    '
  C.3.5:
  - 'Land, Ocean, Food, and Water

    '
  C.3.6:
  - 'Land, Ocean, Food, and Water

    '
  - 'Co-Benefits of Adaptation and Mitigation for Sustainable Development Goals

    '
  C.3.7:
  - 'Health and Nutrition

    '
  C.3.8:
  - 'Society, Livelihoods, and Economies

    '
  C.4.1:
  - 'Equity and Inclusion in Climate Change Action

    '
  - 'Co-Benefits of Adaptation and Mitigation for Sustainable Development Goals

    '
  C.4.2:
  - 'Synergies and trade-offs, costs and benefits

    '
  - 'Co-Benefits of Adaptation and Mitigation for Sustainable Development Goals

    '
  - 'Integration of Near-Term Actions Across Sectors and Systems

    '
  C.4.3:
  - 'Benefits of Strengthening Near-Term Action

    '
  - 'Cities, Settlements and Infrastructure

    '
  - 'Health and Nutrition

    '
  - 'Co-Benefits of Adaptation and Mitigation for Sustainable Development Goals

    '
  - 'Integration of Near-Term Actions Across Sectors and Systems

    '
  C.5.1:
  - 'Equity and Inclusion in Climate Change Action

    '
  C.5.2:
  - 'Equity and Inclusion in Climate Change Action

    '
  C.5.3:
  - 'Equity and Inclusion in Climate Change Action

    '
  - 'Cities, Settlements and Infrastructure

    '
  - 'Health and Nutrition

    '
  - 'Society, Livelihoods, and Economies

    '
  C.5.4:
  - 'Observed Changes, Impacts and Attribution

    '
  - 'Equity and Inclusion in Climate Change Action

    '
  C.6.1:
  - 'Mitigation Actions to Date

    '
  - 'Governance and Policy for Near-Term Climate Change Action

    '
  C.6.2:
  - 'Responses Undertaken to Date

    '
  - 'Governance and Policy for Near-Term Climate Change Action

    '
  C.6.3:
  - 'Equity and Inclusion in Climate Change Action

    '
  - 'Governance and Policy for Near-Term Climate Change Action

    '
  C.6.4:
  - 'Mitigation Actions to Date

    '
  - 'Governance and Policy for Near-Term Climate Change Action

    '
  C.6.5:
  - 'Equity and Inclusion in Climate Change Action

    '
  - 'Society, Livelihoods, and Economies

    '
  - 'Governance and Policy for Near-Term Climate Change Action

    '
  C.7.1:
  - 'Finance for Mitigation and Adaptation Actions

    '
  C.7.3:
  - 'Finance for Mitigation and Adaptation Actions

    '
  C.7.4:
  - 'Finance for Mitigation and Adaptation Actions

    '
  C.7.5:
  - 'Technology Innovation, Adoption, Diffusion and

    '