Heat-related deaths around the world will increase as deadly heat waves become more common with rising global temperatures that are associated with climate change, according to 2 new reports.
In the first study published in Nature Climate Change, an international group of investigators found that 30% of the world’s population is currently exposed to potentially deadly heat for 20 days or more per year. To predict the likelihood of future deadly heat waves, the researchers identified 783 lethal heat waves in 164 cities across 36 countries that occurred between 1980 and 2014, most recorded in developed countries at mid-latitudes, including New York, Chicago, Beijing, Sao Paolo, and Moscow. By analyzing the climatic conditions of these lethal heat events, the investigators identified a threshold beyond which daily mean temperatures and relative humidity became deadly. Their findings suggest that by 2100, even if greenhouse gases are aggressively reduced, at least 48% of the global population will face deadly heat waves, and if emissions are not curtailed, 74% of people around the world could face deadly heat waves.
In the second study published in ScienceAdvances, a separate group of international researchers reported that as the mean summer temperatures across India have increased, the number, intensity, and duration of heat waves as well as days in which they occurred have also increased. Using data from the India Meteorological Department, the investigators found that summer mean temperatures across India rose by more than 0.5°C from 1960 to 2009, which has increased the probability of mass heat-related mortality (heat-related deaths of >100 people) by a factor of 2.5, from 13% to 32%. Similarly, the probability of heat-related mass mortality events would increase from 46% to 82% when the average number of heat wave days across India increases from 6 to 8, respectively. Previous studies suggest India’s temperature will rise from 2.2°C to 5.5°C by the end of the 21st century, which could have a drastic effect on human life.
read more at JAMA