Climate scientists said on Monday that global warming has greatly exacerbated the severe heat wave that is affecting much of Pakistan and India this spring and has increased the likelihood of it occurring.
According to scientists, the likelihood of such a heat wave has increased at least 30 times since the 19th century, before widespread emissions of the gases that warm the Earth began. The heat wave is on average one degree centigrade warmer than a similar event that occurred in those pre-industrial times, the researchers said.
“Climate change really changes everything when it comes to heat waves,” said Friedrich Otto, a climatologist at Imperial College London. “It’s a factor of greater importance.” Otto is the author of a report on the World Weather Attribution Heat Wave, a collaborative effort by scientists to investigate extreme weather events to see whether they have been affected by climate change.
Persistent heat, with temperatures rising above 38 degrees centigrade, has already killed at least 90 people, particularly in northwestern India and southeast Pakistan, triggered by melting glaciers in the Himalayas , electricity has contributed and India’s wheat crop has been affected. Help fuel an emerging global food crisis.
The study concluded that such a heat wave has about a 1 in 100 chance of occurring in any given year. Before climate warming began, the odds would have been 1 in 3,000 or less. And the chances will rise to 1 in 5, the scientists said, if the world reaches 2 degrees Fahrenheit, which it is on track to do, unless countries drastically reduce their emissions. The world has already warmed by about 1.1 °C since the late 19th century.
Summer is normal in South Asia at this time of year, but the current heat wave has begun near the beginning of March, and continues in some areas where there is little chance of respite until monsoon rains arrive in the next few years. ,
The scientists analyzed daily maximum temperatures from March and April and used computer simulations of the world as it is today and a hypothetical world with neither emissions nor warming. The study was not peer-reviewed, but these model-matching techniques were peer-reviewed in the past and are now widely used and accepted.
Because of a long observational record and the absence of other uncertainties, the researchers said, the findings are conservative, and the likelihood of such an event is 30 times more likely than previously thought for the planet’s warming.
The analysis also examined the effects of prolonged heat. Arpita Mandal, a climatologist at the Bombay Institute of Technology in Mumbai and one of the study’s authors, said it was difficult to gather data on the effects of a heat wave on wheat, which is sensitive to extreme heat, but there were anecdotal reports. Harm.
“But one thing that was surprising was that India banned the export of wheat to the rest of the world,” she said. “This is the only evidence that our agricultural productivity has been affected.”
Besides the impact on Ukraine’s wheat exports of the Russian invasion of Ukraine, India’s export ban is leading international agencies to fear a possible global famine.
Another study author, Roop Singh, climate risk advisor at the Red Cross Red Crescent Climate Center, said this heat wave, like others, shows that the impact is felt disproportionately by the poor.
According to Singh, there are reports of widespread power cuts, partly because the need for more cooling puts pressure on the system and partly because of the coal shortage in India. “This has a special impact on the poorest people, who may have access to a fan or air conditioner but may not be able to run it because they cannot afford a generator,” she explained.
The study’s findings are consistent with several other analyzes of similar events over the past two decades, including an extraordinary heat wave last summer in the Pacific Northwest and western Canada. Known as attribution analysis, this field of research has contributed to a growing understanding among scientists and the public that the harmful effects of global warming are not a problem of the distant future, but are already occurring.
As emissions have raised the world’s base temperatures, the link between heat waves and climate change is particularly clear. Otto said that in studies of other extreme events such as floods or droughts, climate change is often only one factor among many taken into account.
In a recent paper, she and other scientists argued that the effect of global warming on heat waves is already so clear that “it is rapidly becoming an obsolete question.” He wrote that the next frontier of attribution science will provide information to help people decide when to adapt to extreme heat.
Translation by Clara Allen
