Climate change causes more than one-third of global heat-related deaths each year, new research published Monday in Nature Climate Change finds. Seventy scientists assessed heat deaths in 732 cities from 1991 to 2018 and found 37% of deaths world-wide were directly attributable to climate change. In total they found an average of 9,700 deaths a year, just from the selected cities, could be blamed on human-caused heating. In the 200 US cities studied, the average was 1,100 deaths annually, about 35% due to climate change, while Hawaii had the highest proportion of climate-attributable deaths at 82%. “These are deaths related to heat that actually can be prevented. It is something we directly cause,” Ana Vicedo-Cabrera, an epidemiologist at the Institute of Social and Preventive Medicine at the University of Bern in Switzerland, told the AP.

Climate change harming health now

“People continue to ask for proof that climate change is already affecting our health. This attribution study directly answers that question using state-of-the-science epidemiological methods, and the amount of data the authors have amassed for analysis is impressive,” Dr. Jonathan Patz, director of the Global Health Institute at the University of Wisconsin, who was not involved in the study, told the AP. The study applied models used to calculate the number of deaths caused by climate change in an individual heatwave, and is the first to apply that methodology to hundreds of locations across decades — enabling the scientists to draw broader conclusions.

“It is a thoughtful, insightful, clever approach to try to understand how climate change is altering heat-related mortality,” Kristie L. Ebi, a professor in the Center for Health and the Global Environment at the University of Washington who was not involved in the study, told the New York Times.

The study’s findings were published as Thomson Reuters reported “heat shocks” driven by climate change are threatening Bangladeshi food supplies, cities around the world are naming “heat officers” to address the dangers posed by climate change, and the British Met Office warned heat will kill thousands in the U.K. (Study: AP, AP (es), New York Times $, Bloomberg $; Bangladesh: Thomson Reuters Foundation; Cities: Thomson Reuters Foundation; UK: The Guardian; (Climate Signals background: Extreme heat and heatwaves)