More than one in three heat-related deaths worldwide can be attributed to anthropogenic climate change, according to a paper published in Nature Climate Change.
In an analysis of almost 30 million deaths in 43 countries, with data from 1991 to 2018, the study found that 37% of the deaths on average were the result of human-induced global warming, with the proportion rising to more than 75% in some places.
“Increased mortality is evident on every continent,” said the paper, which includes contributions from at least 70 scientists. “Burdens varied geographically but were of the order of dozens to hundreds of deaths per year in many locations.”
The paper shows that the level of warming varies across the globe, with some places recording little change from pre-industrial times, while others have seen average temperatures rise by well over 1 degree Celsius. Similarly, the level of mortality due to higher temperatures varies widely. For example, a 31 degree (88 degrees Fahrenheit) day in Chicago — the 99th percentile of the warm season — was associated with a 36% increase in mortality risk, according to the study. But a 28 degree day in Berlin (the 99th percentile for that city) raised the risk by 57%.
The results indicate that some of the worst-affected countries are in southern Europe, with Spain, Greece and Italy suffering some of the largest increases in heat-related mortality due to climate change. Other regions hit hard include Iran and Kuwait, Thailand and the Philippines in Southeast Asia, and several countries in Central and South America.