Record European heat killed over 50,000 people this summer, study finds

Record-breaking heat in Europe this summer contributed to the deaths of more than 50,000 people, according to a new study. The research, to be published in Nature Health, found that 50,391 people died from warmer temperatures across 854 European cities during repeated heat waves in June, July and August. Of those deaths, 32,619 were due to the extra heat caused by the burning of fossil fuels, the study concluded. The death toll is 71 per cent higher than the previous deadliest summer recorded by the same researchers, which saw 29,480 heat-related deaths in 2022.

Study authors said the figures are likely underestimates because they do not include a deadly heat wave in May and only cover cities representing about 40 per cent of Europe's population. About one-third of the deaths occurred during an intense heat wave from June 17 to July 1, when temperatures were 5.3 degrees Celsius above normal, said study co-author Garyfallos Konstantinoudis, a biostatistician at Imperial College London. Italy, France, Spain and Germany had the highest death tolls. "Much of Western and Northern Europe, our infrastructure is just not designed to cope with the sort of temperatures that we are seeing now because of the effects of human-caused warming," said lead author Clair Barnes, a climate scientist at Imperial College London. She noted some European cities this summer had temperatures 12 C warmer than normal. Barnes said Europe is the fastest-warming continent and is now 2.5 C hotter than pre-industrial times.

More than half of those who died were age 85 or older, but the heat also killed more than 800 people between the ages of 20 and 44, Konstantinoudis said. The researchers used an established scientific method, running computer simulations of a world without climate change and comparing the results with the deaths that happened this summer. The difference, they determined, was caused by global warming. Barnes said the percentage of heat deaths attributable to global warming has grown from about 45 per cent in the early 2000s to 65 per cent now.

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The scientific team used statistical modelling to arrive at the base count of 50,000 heat deaths because such deaths are often underreported and not listed on death certificates, Konstantinoudis explained. Several outside experts agreed with the methodology, calling it state-of-the-art. The researchers ran a complex mathematical equation factoring in specific ages and temperatures for each city based on a localized optimal temperature linked to the fewest deaths. They checked their calculations against real-time estimates from government agencies, which mostly matched well. For example, the team's methods for May and June British heat waves calculated 2,700 excess deaths, while the United Kingdom health statistics agency reported 2,800, Konstantinoudis said. "Summers are getting hotter, and the analytical tools for attributing deaths to heat are getting more accurate," said Dr. Howard Frumkin, former director of the U.S. National Center for Environmental Health, who was not part of the study.

Canadian emergency room physician Dr. Courtney Howard, president-elect of the Canadian Medical Association, said urgent action is needed. "We need to prepare for the heat we cannot now avoid, with urgent investments in heat early-warning systems, equitable access to low-carbon cooling, and neighborhood buddy systems that check on and support people most at risk, while rapidly reducing the fossil fuel use driving the crisis," said Howard, who was not part of the research. Dr. Jonathan Patz of the University of Wisconsin-Madison, who also praised the study, said adaptation is only part of the answer. "We can't just be mopping up the mess on the floor without thinking about turning the faucet off," said Patz, a professor of health and the environment. "So we need prevention at different levels. We need better cooling and protecting vulnerable populations from inevitable increased frequency and extreme heat waves. But we also need to go to the root of the problem and absolutely address the burning of fossil fuels." The findings come after a summer where August set a global heat record, with the global average temperature 1.65 C above the pre-industrial average.

With files from CBC News and NPR