South Asia, where one-fifth of the world's people live, could face summer heat waves that are impossible to survive without protection, thanks to global warming, new research suggests. Hardest hit regions are in northern India, Bangladesh, and southern Pakistan, home to 1.5 billion people. These are also among the poorest regions in South Asia. Many are dependent on subsistence farming that requires long hours of hard outdoor labor.

"That makes them very vulnerable to these climatic changes,” said MIT professor of environmental engineering Elfatih Eltahir, one of the co-authors.

The study shows that on the current business-as-usual trajectory of carbon emissions these deadly heat waves could hit the region within a few decades with potentially devastating impacts on the fertile Indus and Ganges River Basins that produce much of the region's food supply.

However, cuts in carbon emissions as pledged under the 2015 Paris Climate Agreement dramatically reduces the risk to the region.

“Emission cuts will make a big difference in the lives of the most vulnerable people in the region. This is not an abstract concept,” said Eltahir.

The study, published Wednesday in Science Advances, used state-of-the-art climate models to project potential future heat and humidity in South Asia, already one of the warmest regions of the world. Hot weather's most deadly effects result from a combination of high temperature and high humidity, called a wet-bulb temperature. A temperature of 94 degrees Fahrenheit (34.4 degrees Celsius) and 80% humidity produces a wet-bulb or “feels like” temperature of 129 degrees Fahrenheit (53.9 degrees Celsius) on the NOAA National Weather Service Heat Index. This is considered extremely dangerous without some way to cool down.

Climate Change 101 with Bill Nye

At a wet-bulb temperature of 35 degrees Celsius or 167 degrees Fahrenheit “feels like” (100 degrees Fahrenheit with 85% humidity for example), the human body cannot cool itself enough to survive more than a few hours. Such conditions are quite rare currently. However, lower temperatures are often deadly. A 2015 heat wave that killed at least 3,500 in India and Pakistan saw wet-bulb temperatures around 122 degrees Fahrenheit (50 degrees Celsius). A similar wet-bulb temperature was reached during the 1995 Chicago heat wave.

Currently about two percent of the Indian population sometimes gets exposed to extremes of 32-degree Celsius wet-bulb temperatures. According to Eltahir’s study, without carbon emissions cuts that will increase to about 70 percent of the population by 2100. And about two percent of the people will sometimes be exposed to the survivability limit of 35 degrees Celsius.

Heat Drives Human Migration

The rural poor have little capacity to cope with extreme heat and they are likely to move into cities in search of water, food, and cooling, said Robert McLeman, an expert on climate and migration at Canada’s Wilfred Laurier University.

“One study in Bangladesh showed that extreme heat is more likely to drive migration than flooding is,” McLeman said.

Future sea level rise gets far more attention and study than increases in extreme heat, which may actually have a larger impact a lot sooner. “No one’s really figured out practical solutions yet,” he said.

However, at a conference in Portland, Oregon, last year city officials from the northwest states met to discuss how to cope with the growing migration of people from California and the southwest who are moving because it’s getting hotter, said McLeman, a speaker at the meeting.

“Officials know more people are coming and they’re trying to figure out how to deal with that.”

While Florida and the southeast states will also face more extreme heat, America’s dangerous heat zone is in the middle of the country from Minnesota, along the Mississippi River Valley to New Orleans, said Richard Rood, a meteorologist and climate expert at the University of Michigan.

“Places like St Louis and Chicago often experience extended periods of hot and humid weather while extremes in coastal states are moderated by the ocean,” Rood said.

The U.S. has already experienced record heat waves with just 1C of warming from climate change. Without making carbon emission cuts the future will bring average increases of more than 4 degrees. That will be a “vastly different world,” he said.

For the past 20 to 30 years large numbers of American retirees, young professionals, and others have moved from the north to the south. In the future Rood says there will be a reverse migration back north to escape relentless heat in the southern half of the country.

People in the Middle East and parts of Africa are already moving because of extreme heat and drought, he said.

“Reducing our carbon emissions now will really make a difference in the future.”</s>Heat in South Asia could exceed survivable levels by 2100

A girl cools off in a fountain as a heatwave hits south of France in Nice, France August 2, 2017. — Reuters pic MIAMI, Aug 3 — South Asia, home to one-fifth of the world’s population, could see humid heat rise to unsurvivable levels by century’s end if nothing is done to halt global warming, researchers said yesterday.

The study in the journal Science Advances warned of “summer heat waves with levels of heat and humidity that exceed what humans can survive without protection.”

The research is based on two climate models.

One is a “business-as-usual” scenario in which little is done to contain climate change, and the second is aimed at limiting temperature rise to well below 2º Celsius, as pledged by more than 190 nations under the 2015 Paris climate accord.

The study is the first of its kind to look not just at temperatures, but at the forecast of “wet-bulb temperature,” which combines temperature, humidity and the human body’s ability to cool down in response.

The survivability threshold is considered to be 35º Celsius, or 95º Fahrenheit.

Under a business-as-usual scenario, “wet-bulb temperatures are projected to approach the survivability threshold over most of South Asia, and exceed it at a few locations, by the end of the century,” said the report.

About 30 per cent of the population in the region would be exposed to these harmful temperatures, up from zero per cent at present, said the report.

The densely populated farming regions of South Asia could fare the worst, because workers are exposed to heat with little opportunity for escape into air-conditioned environments.

“Deadly heat waves could begin within as little as a few decades to strike regions of India, Pakistan, and Bangladesh, including the fertile Indus and Ganges river basins that produce much of the region’s food supply,” said the report.

Indian is home to 1.25 billion people, while another 350 million live in Bangladesh and Pakistan.

Already in 2015, the fifth deadliest heat wave in modern history swept over large parts of India and Pakistan, killing some 3,500 people.

But researchers said their models gave cause for hope, too. Under the scenario in which steps are taken to limit warming over the coming decades, the population exposed to harmful wet-bulb temperatures would increase from zero to just two per cent.

Temperatures would still reach dangerous levels (over 31º Celsius), but would not be quite so close to the fatal threshold.

“There is value in mitigation, as far as public health and reducing heat waves,” said lead author Elfatih Eltahirhe, professor of environmental engineering at the Massachusetts Institute of Technology (MIT).

“With mitigation, we hope we will be able to avoid these severe projections. This is not something that is unavoidable.” — AFP</s>Temperatures in heavily populated South Asia will exceed habitable levels by the end of this century without efforts to stem manmade climate change, according to new research .

Researchers behind the study, published in the journal Science Advances, found that 4% percent of the South Asian population is expected to experience temperature and humidity conditions in which humans cannot survive without air conditioning by 2100. Three quarters of the population will experience environmental conditions considered dangerous, even if not downright unlivable.

The effects of unchecked temperature rise would extend beyond the health concerns associated with being outside in high temperatures. With workers unable to stay outdoors for extended periods of time, the region's economy and agricultural output would decline, experts say. “With the disruption to the agricultural production, it doesn’t need to be the heat wave itself that kills people," says study author Elfatih Eltahir, a professor of civil and environmental engineering at the Massachusetts Institute of Technology, in a press release . "Production will go down, so potentially everyone will suffer.”

Currently, extreme unhealthy temperatures in South Asia—a region that includes India, Pakistan and Bangladesh—affect around 15% of the region's population. A number of deadly extreme weather events in the region reflect that reality, including a 2015 heat wave that killed more than 2,500 people.

Researchers note that the disastrous scenario could be avoided if countries meet their commitments to keep temperatures from rising more than 2°C (3.6°F) by 2100. That goal, embedded in the 2015 Paris Agreement on climate change, will likely be difficult to meet without increasingly ambitious efforts to reduce greenhouse gas emissions.

South Asia ranks high on lists of the most threatened regions, but it is far from the only place where scientists say global warming could change the fabric of society. In a 2015 study in the journal Nature Climate Change , Eltahir found that a number of Persian Gulf cities would reach similarly unlivable temperature thresholds by 2100.

"We have built entire infrastructures with particular temperatures in mind," Matthew T. Huber, an associate professor of geography at Syracuse University, told TIME earlier this year. "When temperatures get really high, we don’t have the material capacity to deal with that."</s>Venturing outdoors could become deadly across various parts of South Asia by the end of the century as climate change drives heat and humidity to new extremes, a new study suggests.

According to the researchers at the Massachusetts Institute of Technology (MIT) and Hong Kong University of Science and Technology, the Indo-Gangetic Plain that stretches across India, Pakistan and Bangladesh could become too unbearable to reside 70 years from now.

The region is believed to be home to around 1.5 billion people.

“The most intense hazard from extreme future heat waves is concentrated around the densely populated agricultural regions of the Ganges and Indus river basins,” the study authors wrote.

While most climate studies have been mostly based on temperature projections, this one also considers humidity as well as the body’s ability to cool down in response to the weather.

Those three factors together make up what is called a “wet-bulb temperature,” which is the air temperature taken when a wet cloth is wrapped around the thermometer and can help estimate how easy it is for water to evaporate.

Scientists say humans can survive a wet-bulb temperature of up to about 35C, beyond which the human body has difficulty in sweating, leading to heat stroke and ultimately death within just a few hours. This can even occur in shaded, ventilated conditions.

So far, wet bulb temperatures have rarely exceeded 31C, a level that is already considered extremely hazardous.

“It is hard to imagine conditions that are too hot for people to survive for more than a few minutes, but that is exactly what is being discussed in this paper,” said Stanford University climate scientist Chris Field, who was not involved in the study.

“And of course, the danger threshold for punishing heat and humidity is lower for people who are ill or elderly.”

Most of those at risk in India, Pakistan and Bangladesh are poor farmers or outdoor construction workers who are unlikely to have air conditioners.

“What we see in this study is a convergence of intense weather projections and acute vulnerability,” said study co-author Elfatih AB Eltahir of MIT.

For the study, the researchers carried out computer simulations using global atmospheric circulation models under two scenarios – one in which the world comes close to meeting its goal of curbing emissions to limit Earth’s average temperature rise to 2C above pre-industrial levels, and one if it continues emitting at current levels.

Both scenarios play out dangerously for South Asia. But with no limit on global warming, about 30% of the region could see dangerous wet bulb temperatures above 31C on a regular basis within just a few decades.

The researchers say if the world can limit global warming, that risk exposure declines drastically.

Experts say countries must work towards meeting the Paris agreement goals to limit average global warming to 2C, especially since the world has already warmed by 1C.

That average will play out differently across the planet, and South Asia is expected to be hit harder than other regions.

Deadly heat is already common in that part of the world. In 2015, a heat wave across India and Pakistan killed 3,500 people.

Disaster management officials already have urged India’s cities and states to create heat action plans, after recording 13 of the country’s hottest 15 years on record since 2002.

The research is published in the journal Science Advances.</s>Scientists warn much of south Asia could be too hot to live in by 2100</s>Climate change could make much of South Asia – home to a fifth of the world’s population – too hot for human survival by the end of this century, scientists warned on Wednesday.

If climate change continues at its current pace, deadly heatwaves beginning in the next few decades will strike parts of India, Pakistan and Bangladesh, according to a study based on computer simulations by researchers at the Massachusetts Institute of Technology (MIT).

Key agricultural areas in the Indus and Ganges river basins will be particularly hard-hit, reducing crop yields and increasing hunger in some of the world’s most densely populated regions, researchers said.

“Climate change is not an abstract concept, it is impacting huge numbers of vulnerable people,” MIT professor Elfatih Eltahir told the Thomson Reuters Foundation.

“Business as usual runs the risk of having extremely lethal heat waves.”

The areas likely to be worst affected in northern India, southern Pakistan and Bangladesh are home to 1.5 billion people, said Eltahir, the study’s co-author.

Currently, about 2 per cent of India’s population is sometimes exposed to extreme combinations of heat and humidity; by 2100 that will increase to about 70 per cent if nothing is done to mitigate climate change, the study said.

Heatwaves across South Asia in the summer of 2015 killed an estimated 3,500 people and similar events will become more frequent and intense, researchers said.

Projections show the Gulf region will be the world’s hottest region by 2100 as a result of climate change.

But with small, wealthy populations and minimal domestic food production requirements, oil-rich states in the Gulf will be better able to respond to rising heat than countries in South Asia, Eltahir said.

The study does not directly address migration but researchers said it is likely that millions of people in South Asia will be forced to move due to blistering temperatures and crop failures unless steps are taken to reduce greenhouse gas emissions.

Disaster experts from South Asian countries met in Pakistan last month to launch a toolkit to help city governments develop ways to manage the impact of heatwaves in urban areas.

Ahmedabad, in western India, has already introduced a heat action plan – South Asia’s first early warning system against extreme heatwaves.

Authorities in the city of 5.5 million have mapped areas with vulnerable populations and set up “cooling spaces” in temples, public buildings and malls during the summer.</s>New study reveals that climate change in India, Pakistan and Bangladesh can drive heat and humidity to new extremes.

Venturing outdoors may become deadly across wide swaths of India, Pakistan and Bangladesh by the end of the century as climate change drives heat and humidity to new extremes, according to a new study.

These conditions could affect up to a third of the people living throughout the Indo-Gangetic Plain unless the global community ramps up efforts to rein in climate-warming carbon emissions.

Today, that vast region is home to some 1.5 billion people.

"The most intense hazard from extreme future heat waves is concentrated around the densely populated agricultural regions of the Ganges and Indus river basins," wrote the authors of the study, led by former MIT research scientist Eun-Soon Im, now an assistant professor at the Hong Kong University of Science and Technology.

While most climate studies have been based on temperature projections alone, this one - published on Wednesday in the journal Science Advances - also considers humidity as well as the body's ability to cool down in response.

Those three factors together make up what is called a "wet-bulb temperature", which is the air temperature taken when a wet cloth is wrapped around the thermometer.

It is always lower than the dry-bulb temperature - how much so depends on the humidity. It can help estimate how easy it is for water to evaporate.

It can also offer a gauge for where climate change might become dangerous.

Scientists say humans can survive a wet-bulb temperature of up to about 35 degrees Celsius (95 degrees Fahrenheit), beyond which the human body has difficulty sweating to cool down, or sweat doesn't evaporate, leading to heat stroke and ultimately death within just a few hours - even in shaded, ventilated conditions.

So far, wet bulb temperatures have rarely exceeded 31 C (88-90 degrees F), a level that is already considered extremely hazardous.

Most of those at risk in India, Pakistan and Bangladesh are poor farmworkers or outdoor construction labourers. They are unlikely to have air conditioners - up to 25 percent in of India's population still has no access to electricity.

In some areas that have been deforested for industry or agriculture, they may not even have very much shade.

READ MORE: The case for collaborating on climate change

"What we see in this study is a convergence of intense weather projections and acute vulnerability," co-author and MIT environmental engineering professor Elfatih A.B. Eltahir said.

For the study, the researchers carried out computer simulations using global atmospheric circulation models under two scenarios - one in which the world comes close to meeting its goal of curbing emissions to limit Earth's average temperature rise to 2 degrees C (3.6 degrees F) above pre-industrial levels, and one if it continues emitting at current levels.

Both scenarios play out dangerously for South Asia. But with no limit on global warming, about 30 percent of the region could see dangerous wet bulb temperatures above 31 degrees C (88 degrees F) on a regular basis within just a few decades.

That is nearly half a billion people by today's population levels, though the full scale could change as the population grows. Meanwhile, 4 percent of the population - or 60 million in today's population - would face deadly highs at or above 35 degrees C (95 degrees F) by 2100.

But if the world can limit global warming, that risk exposure declines drastically. About 2 percent of the population would face average wet bulb temperatures of 31 degrees C (88 degrees F) or higher.

"This is an avoidable, preventable problem," Eltahir said. "There is a significant difference between these two scenarios, which people need to understand."

Experts say countries must work toward meeting the Paris agreement goals to limit average global warming to 2 degrees C (3.6 degrees F), especially since the world has already warmed by 1 degree C (1.8 degrees F). That average will play out differently across the planet, and South Asia is expected to be hit harder than other regions.

But while scientists have warned for years that climate change will exacerbate the risks faced by South Asia's poor, including storms, droughts and heat waves, humidity hasn't always been considered.

READ MORE: UN demands more ambition as US weighs climate pullout

For India, it is a key factor. The country is a peninsula that experiences seasonal monsoon rains, which can make a day outdoors in July seem like a suffocating steam room.

Infections fester. Mosquitoes flourish. People lie sprawled atop woven cots for hours a day, moving as little as possible as they wait out the heat.

In 2015, a heat wave across India and Pakistan killed 3,500 people. Disaster management officials already have urged India's cities and states to create heat action plans, after recording 13 of the country's hottest 15 years on record since 2002.</s>India, Pakistan, Bangladesh and other parts of South Asia may experience heat waves, in which people cannot survive, by the end of this century if nothing is done to curb global warming, says a new study. About 30% of the population in the South Asia would be exposed to high temperature coupled with rising humidity.

The study, which was published in the journal Science Advances on Wednesday, warned of “summer heat waves with levels of heat and humidity that exceed what humans can survive without protection”.

Researchers have come up with a “wet bulb temperature” that combines temperature, humidity and the human body’s ability to cool down. A wet bulb temperature of 35°C is considered the upper limit for human survival. The wet bulb temperatures on earth have rarely exceeded 31°C, reported BBC. Only once, in Iran in 2015, during a deadly heat wave, the wet bulb temperature was close to 35°C.

If the UN Paris accord is not followed...

The study takes into account two climate models. One is a “business-as-usual” scenario in which nothing is done to curb global warming, and the other is if steps are taken as per the 2015 Paris climate accord.

If no measures are taken to reduce greenhouse emissions, the densely-populated farming areas of South Asia will be affected the most by this heat and humidity. “Deadly heat waves could begin within as little as a few decades to strike regions of India, Pakistan, and Bangladesh, including the fertile Indus and Ganges river basins that produce much of the region’s food supply,” said the report.

However, the results could change if steps are taken to limit affects of global warming. Researchers said that if the Paris climate accord is followed, only 2% population will be exposed to harmful wet bulb temperatures. But, temperatures will still go over 31°C, according to the study.</s>A new study has shown that temperatures in parts of South Asia could reach unsurvivable levels before the turn of the next century.

The research ties to rising wet-bulb temperature, a way of measuring the air's humidity. Across swathes of India, Pakistan and Bangladesh, coming heat waves could see the wet-bulb temperature reach 35C, considered the upper limit of temperatures humans can survive in.

As the humid air reaches that level, it leaves the human body unable to properly regulate its internal temperature - one that needs to stay within a small margin.

The areas likely to be hit is also a cause for concern - some of the poorest in the region where many live on subsistance farming and hard labour while having little access to services like air conditioning.

The researchers from the Massachusetts Institute of Technology and Loyola Marmount University said that the findings raise new issues of environmental justice around climate change policy discussions.

"In the absence of serious mitigation, some of the most severe hazards associated with climate change will fall on some of the most vulnerable populations," the paper by Eun-Soom Im, Jeremy S. Pal and Elfatih A. B. Eltahir said.

The study also noted the India itself has had rapidly increasing levels of greenhouse gas emissions as its economy and population has boomed. "The findings from this study may present a significant dilemma for India because the continuation of this current trajectory of rising emissions will likely impose significant added human health risks to some of its most vulnerable populations," the study said.

Speaking to the BBC, Professor Eltahir said "climate change doesn't look like an abstract concept if you look at India." Before adding: "This is something that is going to impact your most vulnerable population in ways that are potentially pretty lethal. But it is avoidable, it is preventable."</s>Wheat marked with spray paint grows in research fields at the University of Minnesota's St. Paul campus in Minnesota, July 30, 2009. Reuters Climate change is not only making the planet more at risk for flooding, economic collapse, record heat waves, disease, and extinction of certain animal species — it could also make some food less nutritious.

If carbon-dioxide levels continue to rise as projected, 18 countries may lose over 5% of their dietary protein from staple crops like rice and wheat by 2050, according to a new study by Harvard University.

The findings, published August 2, suggest that 150 million people could face protein deficiency due to the impact of high CO2 levels. This is the first study to quantify the risk of protein deficiency from rising CO2.

Currently, 76% of the world's population derives most of its daily protein from plants. To estimate the current and future risk of protein deficiency, the Harvard researchers analyzed experiments in which crops were exposed to high concentrations of CO2. They also looked at dietary information from the United Nations .

They found that, under elevated CO2 levels, the protein in rice, wheat, barley, and potatoes decreased by 7.6%, 7.8%, 14.1%, and 6.4%, respectively. Essentially, the crops lose some of their ability to absorb nitrate (the most common type of nitrogen in agricultural soil) and convert it into organic compounds, like protein. Those most at risk include 354 million children under 5 and 1.06 billion women—predominantly in South Asia and North Africa — who live in countries already experiencing high rates of protein deficiency.

There's an overwhelming consensus within the scientific community that human activity is contributing to increasing levels of carbon dioxide and methane in the Earth's atmosphere. Recent research also points to a strong link between rising carbon dioxide and rising global temperatures, which are already affecting agriculture in the US and abroad.

Cattle, for example, are less productive when it's warmer, causing some American farmers to install air conditioning in their barns to maintain productivity. High temperatures and CO2 have also been linked to extreme weather events, like hurricanes in Bangladesh and monsoons in Southeast Asia, which can make growing processes more unpredictable for farmers.

Research suggests that the planet will continue too get warmer if countries do not drastically reduce carbon emissions. A recent study, for example, estimates that there's only a 5% chance that the world won't warm more than 2 degrees Celsius by 2100. Most scientists consider that level to be the tipping point when the consequences of climate change become catastrophic.

"This study highlights the need for countries that are most at risk to actively monitor their populations' nutritional sufficiency, and, more fundamentally, the need for countries to curb human-caused CO2 emissions," Samuel Myers, senior research scientist in Harvard's Department of Environmental Health, said in a press release.

Meanwhile, Finnish researchers from the VTT Technical Research Centre recently figured out how to turn excess CO2 into edible protein. The process - which can run on renewable energy — requires electricity and a small amount of water and nutrients. It's one solution for curbing CO2, or at least turning it into something productive.
New research suggests that large parts of Southern Asia may be uninhabitable by 2100 due to levels of humidity dangerous to humans.