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Daniel Marques
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9c42005
1
Parent(s):
7b6b04f
feat: add dataset
Browse files- SOURCE_DOCUMENTS/dataset.txt +417 -0
SOURCE_DOCUMENTS/dataset.txt
CHANGED
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1 |
One of the wettest wet seasons in northern Australia transformed
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large areas of the country’s desert landscape over the course of many months in 2023. A string
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1 |
+
Global climate change is not a future problem. Changes to Earth’s climate driven by increased human
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2 |
+
emissions of heat-trapping greenhouse gases are already having widespread effects on the environment:
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3 |
+
glaciers and ice sheets are shrinking, river and lake ice is breaking up earlier, plant and animal geographic
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ranges are shifting, and plants and trees are blooming sooner.
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Effects that scientists had long predicted would result from global climate change are now occurring,
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such as sea ice loss, accelerated sea level rise, and longer, more intense heat waves.
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+
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+
Some changes (such as droughts, wildfires, and extreme rainfall)
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are happening faster than scientists previously assessed. In fact,
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according to the Intergovernmental Panel on Climate Change (IPCC) — the United Nations
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body established to assess the science related to climate change — modern humans have
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never before seen the observed changes in our global climate, and some of these changes
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are irreversible over the next hundreds to thousands of years.
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+
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Scientists have high confidence that global temperatures will continue to rise
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for many decades, mainly due to greenhouse gases produced by human activities
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+
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+
The IPCC’s Sixth Assessment report, published in 2021, found that human
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emissions of heat-trapping gases have already warmed the climate by nearly 2 degrees Fahrenheit
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+
(1.1 degrees Celsius) since 1850-1900.1 The global average temperature is expected to reach or
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exceed 1.5 degrees C (about 3 degrees F) within the next few decades. These changes will affect all regions of Earth.
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+
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The severity of effects caused by climate change will depend on the path of future human activities.
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More greenhouse gas emissions will lead to more climate extremes and widespread damaging effects
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across our planet. However, those future effects depend on the total amount of carbon dioxide we emit.
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So, if we can reduce emissions, we may avoid some of the worst effects.
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+
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+
What’s the difference between climate change and global warming?
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+
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+
The terms “global warming” and “climate change” are sometimes used interchangeably, but "global warming" is only one aspect of climate change.
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+
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“Global warming” refers to the long-term warming of the planet. Global temperature shows a
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well-documented rise since the early 20th century and most notably since the late 1970s.
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Worldwide since 1880, the average surface temperature has risen about 1°C (about 2°F), relative to
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the mid-20th century baseline (of 1951-1980). This is on top of about an additional 0.15°C of
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warming from between 1750 and 1880.
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“Climate change” encompasses global warming, but refers to the broader range of changes that are
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happening to our planet. These include rising sea levels; shrinking mountain glaciers; accelerating
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ice melt in Greenland, Antarctica and the Arctic; and shifts in flower/plant blooming times.
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These are all consequences of warming, which is caused mainly by people burning fossil fuels
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and putting out heat-trapping gases into the air.
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Global temperature rise from 1880 to 2022. Higher-than-normal
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temperatures are shown in red and lower-than-normal temperatures are shown in blue.
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Each frame represents global temperature anomalies (changes) averaged over the five years
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previous to that particular year. Credit: NASA Goddard Space Flight Center/NASA Scientific
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Visualization Studio/NASA Goddard Institute for Space Studies.
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What Is Climate Change?
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Climate change is a long-term change in the average weather patterns that have come to define Earth’s local,
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regional and global climates. These changes have a broad range of observed effects that are synonymous with the term.
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Changes observed in Earth’s climate since the mid-20th century are driven by human activities, particularly
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fossil fuel burning, which increases heat-trapping greenhouse gas levels in Earth’s atmosphere, raising Earth’s
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average surface temperature. Natural processes, which have been overwhelmed by human activities, can also contribute
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to climate change, including internal variability (e.g., cyclical ocean patterns like El Niño, La Niña and the Pacific
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Decadal Oscillation) and external forcings (e.g., volcanic activity, changes in the Sun’s energy output, variations in Earth’s orbit).
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Scientists use observations from the ground, air, and space, along with computer models, to monitor and study
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past, present, and future climate change. Climate data records provide evidence of climate change key indicators,
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such as global land and ocean temperature increases; rising sea levels; ice loss at Earth’s poles and in mountain
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glaciers; frequency and severity changes in extreme weather such as hurricanes, heatwaves, wildfires, droughts,
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floods, and precipitation; and cloud and vegetation cover changes.
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“Climate change” and “global warming” are often used interchangeably but have distinct meanings. Similarly, the
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terms "weather" and "climate" are sometimes confused, though they refer to events with broadly different
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spatial- and timescales.
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What Is Global Warming?
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Global warming is the long-term heating of Earth’s surface observed since the pre-industrial period
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(between 1850 and 1900) due to human activities, primarily fossil fuel burning, which increases
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heat-trapping greenhouse gas levels in Earth’s atmosphere. This term is not interchangeable with the term "climate change."
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Since the pre-industrial period, human activities are estimated to have increased Earth’s global
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average temperature by about 1 degree Celsius (1.8 degrees Fahrenheit), a number that is currently
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increasing by more than 0.2 degrees Celsius (0.36 degrees Fahrenheit) per decade. The current warming
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trend is unequivocally the result of human activity since the 1950s and is proceeding at
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an unprecedented rate over millennia.
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Weather refers to atmospheric conditions that occur locally over short periods of time—from
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minutes to hours or days. Familiar examples include rain, snow, clouds, winds, floods, or thunderstorms.
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Climate, on the other hand, refers to the long-term (usually at least 30 years) regional or
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even global average of temperature, humidity, and rainfall patterns over seasons, years, or
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decades.
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The Causes of Climate Change
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Four Major Gases That Contribute to the Greenhouse Effect:
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FORCING: Something acting upon Earth's climate that causes a change in how energy flows
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through it (such as long-lasting, heat-trapping gases - also known as greenhouse gases).
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These gases slow outgoing heat in the atmosphere and cause the planet to warm.
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Carbon Dioxide
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A very important component of the atmosphere, carbon dioxide (CO2)
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is released through natural processes (like volcanic eruptions) and through
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human activities, like burning fossil fuels and deforestation.
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Human activities have increased the amount of CO2 in the atmosphere by 50% since the
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Industrial Revolution began (1750). This sharp rise in CO2 is the most important
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climate change driver over the last century.
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Methane
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Like many atmospheric gases, methane comes from both natural and human-caused sources.
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Methane comes from plant-matter breakdown in wetlands and is also released from landfills
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and rice farming. Livestock animals emit methane from their digestion and manure.
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Leaks from fossil fuel production and transportation are another major source of methane,
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and natural gas is 70% to 90% methane. As a single molecule, methane is a far more effective
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greenhouse gas than carbon dioxide but is much less common in the atmosphere. The amount of
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methane in our atmosphere has more than doubled since pre-industrial times.
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Nitrous Oxide
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A potent greenhouse gas produced by farming practices, nitrous oxide is released during
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commercial and organic fertilizer production and use. Nitrous oxide also
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comes from burning fossil fuels and burning vegetation and has increased
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by 18% in the last 100 years.
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Chlorofluorocarbons (CFCs)
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These chemical compounds do not exist in nature – they are entirely of industrial origin. They were used as refrigerants,
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solvents (a substance that dissolves others), and spray-can propellants. An international agreement,
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known as the Montreal Protocol, now regulates CFCs because they damage the ozone layer. Despite this,
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emissions of some types of CFCs spiked for about five years due to violations of the international agreement.
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Once members of the agreement called for immediate action and better enforcement, emissions dropped sharply starting in 2018.
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Another Gas That Contributes to the Greenhouse Effect:
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Water Vapor
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Water vapor is the most abundant greenhouse gas,
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but because the warming ocean increases the amount of it in our atmosphere,
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it is not a direct cause of climate change. Rather, as other forcings (like carbon dioxide)
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change global temperatures, water vapor in the atmosphere responds, amplifying climate change
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already in motion. Water vapor increases as Earth's climate warms. Clouds and precipitation
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(rain or snow) also respond to temperature changes and can be important feedback mechanisms as well.
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Human Activity Is the Cause of Increased Greenhouse Gas Concentrations
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Over the last century, burning of fossil fuels like coal and oil has increased the concentration of
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atmospheric carbon dioxide (CO2). This increase happens because the coal or oil burning process
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combines carbon with oxygen in the air to make CO2. To a lesser extent, clearing of land for agriculture,
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industry, and other human activities has increased concentrations of greenhouse gases.
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How do we know what greenhouse gas and temperature levels were in the distant past?
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The industrial activities that our modern civilization depends upon have raised atmospheric
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carbon dioxide levels by nearly 50% since 17502. This increase is due to human activities, because
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scientists can see a distinctive isotopic fingerprint in the atmosphere.
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In its Sixth Assessment Report, the Intergovernmental Panel on Climate Change, composed of
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scientific experts from countries all over the world, concluded that it is unequivocal that
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the increase of CO2, methane, and nitrous oxide in the atmosphere over the industrial era is
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the result of human activities and that human influence is the principal driver of many changes
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observed across the atmosphere, ocean, cryosphere and biosphere.
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How do we know what greenhouse gas and temperature levels were in the distant past?
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Ice cores are scientists’ best source for historical climate data. Every winter, some snow coating Arctic
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and Antarctic ice sheets is left behind and compressed into a layer of ice. By extracting cylinders of ice
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from sheets thousands of meters thick, scientists can analyze dust, ash, pollen and bubbles of atmospheric
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gas trapped inside. The deepest discovered ice cores are an estimated 800,000 years old. The particles trapped
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inside give scientists clues about volcanic eruptions, desert extent and forest fires. The presence of certain
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ions indicates past ocean activity, levels of sea ice and even the intensity of the Sun. The bubbles can be
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released to reveal the make-up of the ancient atmosphere, including greenhouse gas levels.
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Other tools for learning about Earth’s ancient atmosphere include growth rings in trees,
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which keep a rough record of each growing season’s temperature, moisture and cloudiness
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going back about 2,000 years. Corals also form growth rings that provide information about
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temperature and nutrients in the tropical ocean. Other proxies, such as benthic cores,
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extend our knowledge of past climate back about a billion years.
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Evidence Shows That Current Global Warming Cannot Be Explained by Solar Irradiance
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Scientists use a metric called Total Solar Irradiance (TSI) to measure the changes in
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energy the Earth receives from the Sun. TSI incorporates the 11-year solar cycle and solar flares/storms from the Sun's surface.
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Studies show that solar variability has played a role in past climate changes.
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For example, a decrease in solar activity coupled with increased volcanic activity
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helped trigger the Little Ice Age.
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But several lines of evidence show that current global warming cannot be explained by changes in energy from the Sun:
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Since 1750, the average amount of energy from the Sun either remained constant or decreased slightly3.
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If a more active Sun caused the warming, scientists would expect warmer temperatures
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in all layers of the atmosphere. Instead, they have observed a cooling in the upper
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tmosphere and a warming at the surface and lower parts of the atmosphere.
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That's because greenhouse gases are slowing heat loss from the lower atmosphere.
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Climate models that include solar irradiance changes can’t reproduce the observed
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temperature trend over the past century or more without including a rise in greenhouse gases.
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What Is Climate Change?
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Climate change describes a change in the average conditions — such as temperature and rainfall —
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in a region over a long period of time. NASA scientists have observed Earth’s surface is warming,
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and many of the warmest years on record have happened in the past 20 years.
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Weather describes the conditions outside right now in a specific place. For example,
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if you see that it’s raining outside right now, that’s a way to describe today’s weather.
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Rain, snow, wind, hurricanes, tornadoes — these are all weather events.
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Climate, on the other hand, is more than just one or two rainy days. Climate describes the
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weather conditions that are expected in a region at a particular time of year.
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Is it usually rainy or usually dry? Is it typically hot or typically cold? A region’s climate is
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determined by observing its weather over a period of many years—generally 30 years or more.
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So, for example, one or two weeks of rainy weather wouldn’t change the fact that Phoenix typically
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has a dry, desert climate. Even though it’s rainy right now, we still expect Phoenix to be dry
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because that's what is usually the case.
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Climate change describes a change in the average conditions — such as temperature and rainfall — in a
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region over a long period of time. For example, 20,000 years ago, much of the United States was covered in
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glaciers. In the United States today, we have a warmer climate and fewer glaciers.
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Global climate change refers to the average long-term changes over the entire Earth. These include warming
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temperatures and changes in precipitation, as well as the effects of Earth’s warming, such as:
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Rising sea levels
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Shrinking mountain glaciers
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Ice melting at a faster rate than usual in Greenland, Antarctica and the Arctic
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Changes in flower and plant blooming times.
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Earth’s climate has constantly been changing — even long before humans came into the picture. However, scientists
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have observed unusual changes recently. For example, Earth’s average temperature has been increasing much more
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quickly than they would expect over the past 150 years.
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How Much Is Earth’s Climate Changing Right Now?
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Some parts of Earth are warming faster than others. But on average, global air temperatures near
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Earth's surface have gone up about 2 degrees Fahrenheit in the past 100 years. In fact, the past five
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years have been the warmest five years in centuries.
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Many people, including scientists, are concerned about this warming. As Earth’s climate continues to warm,
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the intensity and amount of rainfall during storms such as hurricanes is expected to increase.
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Droughts and heat waves are also expected to become more intense as the climate warms.
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When the whole Earth’s temperature changes by one or two degrees, that change can have big
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impacts on the health of Earth's plants and animals, too.
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There are lots of factors that contribute to Earth’s climate. However, scientists agree that Earth has been
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getting warmer in the past 50 to 100 years due to human activities.
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Certain gases in Earth’s atmosphere block heat from escaping. This is called the greenhouse effect. These gases
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keep Earth warm like the glass in a greenhouse keeps plants warm.
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Human activities — such as burning fuel to power factories, cars and buses — are changing the natural greenhouse.
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These changes cause the atmosphere to trap more heat than it used to, leading to a warmer Earth.
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What are greenhouse gases?
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Greenhouse gases are gases in Earth’s atmosphere that trap heat.
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They let sunlight pass through the atmosphere, but they prevent the heat that the sunlight brings from leaving
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the atmosphere. The main greenhouse gases are:
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Water vapor
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Carbon dioxide
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Methane
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Ozone
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Nitrous oxide
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Chlorofluorocarbons
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+
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Greenhouse gases are gases that can trap heat. They get their name from greenhouses.
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A greenhouse is full of windows that let in sunlight. That sunlight creates warmth.
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The big trick of a greenhouse is that it doesn’t let that warmth escape.
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That’s exactly how greenhouse gases act. They let sunlight pass through the atmosphere,
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but they prevent the heat that the sunlight brings from leaving the atmosphere. Overall,
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greenhouse gases are a good thing. Without them, our planet would be too cold, and life as
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we know it would not exist. But there can be too much of a good thing. Scientists are worried
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that human activities are adding too much of these gases to the atmosphere.
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+
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How Do We Know Climate Change Is Real?
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While Earth’s climate has changed throughout its history, the
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current warming is happening at a rate not seen in the past 10,000 years.
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+
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According to the Intergovernmental Panel on Climate Change (IPCC),
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"Since systematic scientific assessments began in the 1970s, the influence
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of human activity on the warming of the climate system has evolved from theory to established fact."1
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Scientific information taken from natural sources (such as ice cores, rocks, and tree rings)
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and from modern equipment (like satellites and instruments) all show the signs of a changing climate.
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From global temperature rise to melting ice sheets, the evidence of a warming planet abounds.
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+
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The rate of change since the mid-20th century is unprecedented over millennia.
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Earth's climate has changed throughout history. Just in the last 800,000 years, there have been eight
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cycles of ice ages and warmer periods, with the end of the last ice age about 11,700 years
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ago marking the beginning of the modern climate era — and of human civilization. Most of
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these climate changes are attributed to very small variations in Earth’s orbit that change
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the amount of solar energy our planet receives.
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+
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The current warming trend is different because it is clearly the result of
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human activities since the mid-1800s, and is proceeding at a rate not seen over
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many recent millennia.1 It is undeniable that human activities have produced the atmospheric
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gases that have trapped more of the Sun’s energy in the Earth system. This extra energy has warmed
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the atmosphere, ocean, and land, and widespread and rapid changes in the atmosphere, ocean, cryosphere,
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and biosphere have occurred.
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+
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Ice cores drawn from Greenland, Antarctica, and tropical mountain
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glaciers show that Earth’s climate responds to changes in greenhouse gas
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levels. Ancient evidence can also be found in tree rings, ocean sediments,
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coral reefs, and layers of sedimentary rocks. This ancient, or paleoclimate, evidence reveals that
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current warming is occurring roughly 10 times faster than the average rate of warming after an ice age.
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Carbon dioxide from human activities is increasing about 250 times faster than it did from natural
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sources after the last Ice Age.
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+
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Do scientists agree on climate change?
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+
|
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Earth-orbiting satellites and new technologies
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have helped scientists see the big picture, collecting many different types of information
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about our planet and its climate all over the world. These data, collected over many years,
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reveal the signs and patterns of a changing climate.
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+
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Scientists demonstrated the heat-trapping nature of carbon dioxide and other gases in the mid-19th
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century.2 Many of the science instruments NASA uses to study our climate focus on how these gases
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affect the movement of infrared radiation through the atmosphere. From the measured impacts of
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increases in these gases, there is no question that increased greenhouse gas levels warm Earth in
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response.
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+
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The Evidence for Rapid Climate Change Is Compelling:
|
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+
|
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+
Global Temperature Is Rising
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+
The planet's average surface temperature has risen about degrees Fahrenheit (1 degrees Celsius)
|
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+
since the late 19th century, a change driven largely by increased carbon dioxide emissions into
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the atmosphere and other human activities.4 Most of the warming occurred in the past 40 years,
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+
with the seven most recent years being the warmest. The years 2016 and 2020 are tied for the
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warmest year on record.
|
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+
|
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+
The Ocean Is Getting Warmer
|
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+
The ocean has absorbed much of this increased heat,
|
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+
with the top 100 meters (about 328 feet) of ocean showing warming of 0.67 degrees Fahrenheit
|
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+
(0.33 degrees Celsius) since 1969.6 Earth stores 90% of the extra energy
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+
in the ocean.
|
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+
|
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+
Glaciers Are Retreating
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Glaciers are retreating almost everywhere around the world —
|
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+
including in the Alps, Himalayas, Andes, Rockies, Alaska,
|
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+
and Africa.
|
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+
|
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+
The Ice Sheets Are Shrinking
|
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+
The Greenland and Antarctic ice sheets have decreased in mass. Data from NASA's Gravity Recovery
|
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+
and Climate Experiment show Greenland lost an average of 279 billion tons of ice per year between
|
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+
1993 and 2019, while Antarctica lost about 148 billion tons of ice per year.7 Image: The Antarctic Peninsula, Credit: NASA
|
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+
|
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+
Snow Cover Is Decreasing
|
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+
Satellite observations reveal that the amount of spring snow cover in the Northern Hemisphere has
|
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+
decreased over the past five decades and the snow is melting earlier
|
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+
|
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+
Sea Level Is Rising
|
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+
Global sea level rose about 8 inches (20 centimeters) in the last century.
|
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+
The rate in the last two decades, however, is nearly double that of the last century and accelerating slightly every year
|
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+
|
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+
Arctic Sea Ice Is Declining
|
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+
Both the extent and thickness of Arctic sea ice has declined rapidly over the last several decades.
|
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+
|
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+
Extreme Events Are Increasing in Frequency
|
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+
The number of record high temperature events in the United States has been increasing,
|
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+
while the number of record low temperature events has been decreasing, since 1950.
|
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+
The U.S. has also witnessed increasing numbers of intense rainfall events.
|
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+
|
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+
Since the beginning of the Industrial Revolution, the acidity of surface ocean waters has
|
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+
increased by about 30%.13,14 This increase is due to humans emitting more
|
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+
carbon dioxide into the atmosphere and hence more being absorbed into the ocean.
|
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+
The ocean has absorbed between 20% and 30% of total anthropogenic carbon dioxide emissions
|
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+
in recent decades (7.2 to 10.8 billion metric tons per year).
|
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+
|
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+
Solimões and Negro Rivers
|
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+
The largest river on the planet, the Amazon, forms from the confluence of the
|
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+
Solimões (the upper Amazon River) and the Negro at the Brazilian city of Manaus in central Amazonas.
|
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+
At the river conjunction, the muddy, tan-colored waters of the Solimões meet the “black” water of
|
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+
the Negro River. The unique mixing zone where the waters meet extends downstream through the rainforest
|
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+
for hundreds of miles, and attracts tourists from all over the world, which has contributed to substantial
|
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+
growth in the city of Manaus.
|
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+
|
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+
It is the vast quantity of sediment eroded from the Andes Mountains that gives
|
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+
the Solimões its tan color. By comparison, water in the Negro derives from the
|
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+
low jungles where reduced physical erosion of rock precludes mud entering the river.
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+
In place of sediment, organic matter from the forest floor stains the river the color of black tea.
|
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+
|
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+
The Solimões provides nutrient-rich mud to lakes on the floodplain (lower right).
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+
The ecology of muddy lakes differs correspondingly from that of nutrient-poor,
|
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+
blackwater rivers and lakes. Solimões water can be seen leaking into the Negro west of the main
|
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+
meeting zone (lower left). The Solimões is much shallower than the Negro because it has
|
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+
filled its valley and bed with great quantities of sediment since the valleys were excavated.
|
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+
|
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+
NASA is an expert in climate and Earth science. While its role is not to set climate policy or prescribe particular responses or solutions to climate change, its job does include providing the scientific data needed to understand climate change. NASA then makes this information available to the global community – the public, policy-, and decision-makers and scientific and planning agencies around the world. (For more information, see NASA's role.)
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|
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With that said, NASA takes sustainability very seriously. NASA’s sustainability policy is to execute its mission as efficiently as possible. In doing so, we continually improve our space and ground operations.
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+
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Sustainability involves taking action now to protect the environment for both current and future living conditions. In implementing sustainability practices, NASA supports its missions by reducing risks to the environment and our communities.
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|
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In executing its mission, NASA's sustainability objectives are to:
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|
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+
increase energy efficiency;
|
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+
|
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increase the use of renewable energy;
|
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+
|
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+
measure, report, and reduce NASA's direct and indirect greenhouse gas emissions;
|
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+
|
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+
conserve and protect water resources through efficiency, reuse, and stormwater management;
|
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+
|
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+
eliminate waste, prevent pollution, and increase recycling;
|
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+
|
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+
leverage agency acquisitions to foster markets for sustainable technologies and environmentally preferable materials, products, and services;
|
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+
|
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+
design, construct, maintain, and operate high-performance sustainable buildings;
|
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+
|
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+
utilize power management options and reduce the number of agency data centers;
|
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+
|
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+
support economic growth and livability of the communities where NASA conducts business;
|
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+
evaluate agency climate change risks and vulnerabilities and develop mitigation and
|
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+
adaptation measures to manage both the short-and long-term effects of climate change on the agency's mission and operations;
|
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+
|
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+
raise employee awareness and encourage each individual in the NASA community to apply
|
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]the concepts of sustainability to every aspect of their daily work to achieve these goals;
|
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+
|
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maintain compliance with all applicable federal, state, local or territorial law and regulations related to energy security, a
|
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healthy environment, and environmentally-sound operations;
|
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+
and comply with internal NASA requirements and agreements with other entities.
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+
|
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One of the wettest wet seasons in northern Australia transformed
|
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|
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large areas of the country’s desert landscape over the course of many months in 2023. A string
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