Climate breakdown caused more than half of the 68,000 heat deaths during the scorching European summer of 2022, a study has found. Researchers from the Barcelona Institute for Global Health (ISGlobal) found 38,000 fewer people would have died from heat if humans had not clogged the atmosphere with pollutants that act like a greenhouse and bake the planet. The death toll is about 10 times greater than the number of people murdered in Europe that year. “Many see climate change as a future concern,” said the lead author, Thessa Beck. “Yet our findings underscore that it is already a pressing issue.” The warm weather killed more women than men, more southern Europeans than northern Europeans, and more older people than younger people. Scientists already knew carbon pollution had made the heatwaves hotter but did not know how much it had driven up the death toll. They found 56% of the heat-related deaths could have been avoided if the world had not been warmed by burning fossil fuels and the destruction of nature. The share varied between 44% and 54% in the six years prior. Even small increases in temperatures can have devastating impacts on public health, said Emily Theokritoff, a researcher at Imperial College London who was not involved in the study. “This result makes sense – heat-related death increases rapidly as temperatures push past the limits people are acclimatised to.” Europe is warming twice as fast as the rest of the planet but doctors warn its hospitals are not prepared to deal with the consequences. The rise in temperatures forces more people to endure searing summer heat that pushes their bodies into overdrive even as it cuts exposure to chilling winter cold that leaves them too weak to fight off illness. Scientists project the lives lost to hotter summers in Europe will outstrip those saved by cooler winters if the planet heats more than 2C above preindustrial levels. Last week, the UN environment programme warned the world is on track to heat by 3C by the end of the century. The dangers of extreme heat are even greater in Africa, Asia, and South America, but a lack of data had limited studies on how it affects human health, said Beck. “A common misconception is that only extreme temperatures pose a serious risk,” she said. “However, our study, along with previous research, shows that even moderate heat can lead to heat-related deaths, particularly among more vulnerable populations.” Scientists had previously used heat and health data for 35 European countries to estimate how many more people die as a result of hot weather. In the new study, they ran the model with temperatures for a hypothetical world in which humans had not heated the planet. They found climate change was behind 22,501 heat deaths in women and 14,026 heat deaths in men. Garyfallos Konstantinoudis, a researcher at Imperial College London, who was not involved in the study, said the authors may have overestimated the effect of heat on mortality because they did not account for how people had adapted. He said: “Previous studies have reported a decrease in heat-mortality impact over time, due to factors including infrastructural changes and improved health care.” To stay safe in the heat, doctors recommend drinking water, staying indoors during the hottest parts of the day and looking after older neighbours and relatives who live alone. Governments can save lives by creating action plans for hot weather, designing cities with more green space and less concrete, and cutting pollution. “Heat can be very dangerous for the heart, especially for older people,” said Beck.