India is likely to experience deadly heat waves more frequently in the years ahead, even though there only has been a slight increase in human-driven warming over the past few decades, according to a study released Wednesday.
"It's getting hotter, and of course more heat waves are going to kill more people,'' said climatologist Omid Mazdiyasni of the University of California, Irvine, who led an international team of scientists analyzing a half-century of data collected by the Indian Meteorological Department.
After tracking temperature, heat waves and heat-related mortality, Mazdiyasni said, "We knew there was going to be an impact, but we didn't expect it to be this big." The findings are especially sobering considering the average temperature in India rose about one-half of one degree Celsius over 49 years.
The unveiling of the study, published in the journal Science Advances, follows President Donald Trump's decision to pull the United States out of the Paris climate agreement, which aims to limit global warming to 2 degrees Celsius above pre-industrial levels during this century.
The scientists said that, even despite the relatively slight rise in mean temperatures in India between 1960 and 2009, the probability of India experiencing a massive heat-related mortality event - defined by more than 100 deaths - has shot up by 146 percent. Roughly speaking, that means dying in a heat wave in India is now about two and one-half times as likely as it was in the mid-20th century.
Country mostly unprepared
Most of India has experienced a 25 percent rise in the number of heat-wave days during that period. The study's authors said the vast majority of the country's cities and states are not prepared to handle such heat crises, even if they understand the devastation they can wreak.
In 2010, 1,200 people died from heat-related causes in the western city of Ahmedabad, prompting city officials to introduce seven-day weather forecasts and warnings, extra water supplies and cool-air shelters in the summer.
After more than 2,500 people were killed by heat in ravaged areas of India in 2015, nine other cities rolled out a plan to educate children about heat risk, stock hospitals with ice packs and extra water, and train medical workers to identify heat stress, dehydration and heat stroke.
But those nine cities have only about 11 million people, not even 1 percent of the country's population.
The same methodology can be applied in any region to get a sense of how vulnerable a country or population might be, the authors said. Recent events underscore years of warnings by scientists that climate change will make future heat waves more intense, more frequent and longer lasting.