HIBAPRESS-RABAT
“These are heat-related deaths that can actually be prevented. This is something that we are directly causing,” said Ana Vicedo-Cabrera, an epidemiologist at the Institute of Social and Preventive Medicine at the University of Bern in Switzerland.
The highest percentages of heat deaths caused by climate change were recorded in cities in South America. Vicedo-Cabrera said southern Europe and South Asia were other hotspots for heat deaths linked to climate change.
Sao Paulo, Brazil, has the most heat-related deaths linked to global warming, with an average of 239 deaths per year, researchers said.
About 35% of heat deaths in the United States can be attributed to climate change, the study found, or more than 1,100 deaths per year in about 200 U.S. cities — with a peak of 141 in New York City. Honolulu had the highest share of heat deaths attributable to climate change, at 82%.
The scientists used decades of data on mortality in the 732 cities to plot curves detailing how each city’s mortality rate changed with temperature and how heat mortality curves varied from city to city. Some cities adapt better to heat than others because of air conditioning, cultural factors and environmental conditions, Vicedo-Cabrera said.
Then the researchers took the observed temperatures and compared them to 10 computer models that simulated a world without climate change. The difference was in the warming caused by humans. By applying this scientifically accepted technique to individual heat mortality curves for the 732 cities, the scientists calculated the heat-related deaths that are added because of global warming.
“People continue to ask for evidence that climate change is already affecting our health. This study directly answers that question using cutting-edge epidemiological methods, and the amount of data the authors amassed for the analysis is impressive,” observed Dr. Jonathan Patz, director of the University of Wisconsin Global Health Institute.
Mr. Patz, who was not part of the study, said it was one of the first to detail heat deaths linked to climate change now, rather than in the future.
