The analysis also looked at the effects of the prolonged heat. Arpita Mondal, a climate scientist at the Indian Institute of Technology Bombay in Mumbai and an author of the study, said gathering data about the effects on wheat, a crop that is sensitive to extreme heat, was difficult, despite anecdotal reports of damage.
“But what has been quite startling is that India has banned its wheat exports to the rest of the world,” she said. “That in itself is evidence enough that our agricultural productivity has been affected.”
The ban, coupled with the effects of the Russian invasion of Ukraine on wheat exports from there, has international agencies concerned about the potential of a global food shortage.
Another author, Roop Singh, a climate risk adviser with the Red Cross Red Crescent Climate Center, said that, like other heat waves, this one shows that the effects tend to fall disproportionately on the poor.
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She said there have been reports of widespread power outages, in part because the need for more cooling strains the system, and in part because of a coal shortage in India. “This is particularly impactful for the poorest people who might have access to a fan or to a cooler, but might not be able to run it because they can’t afford a generator,” she said.
The findings of the study are consistent with many other analyses of similar events over the past two decades, including an extraordinary heat wave last summer in the Pacific Northwest and Western Canada. This field of research, called attribution analysis, has contributed to a growing understanding among scientists and the public that the damaging effects of global warming are not some far-off problem but are already occurring.
Because emissions have raised the world’s baseline temperature, the link between heat waves and climate change is especially clear. Dr. Otto said that in studies of other extreme events like floods or drought, climate change is usually only one factor among several.