Europe's Summer Heat Killed More Than 50,000 People, Study Finds

Record heat across Europe this summer contributed to the deaths of more than 50,000 people, and researchers say about two-thirds of those deaths trace back to human-caused climate change, according to NPR's report on a new study.

The research, set to appear in an upcoming issue of Nature Health, modeled heat-related deaths by age group in 854 European cities across repeated heat waves in June, July and August. It estimated that 50,391 people died because of warm temperatures, and that 32,619 of those deaths resulted from the additional heat produced by burning coal, oil and gas.

How the toll compares with earlier summers

The same research team found that this year's toll is 71% higher than that of the previous deadliest summer, 2022, when the figure was 29,480, NPR reported. The authors also said the new number is an undercount. It leaves out a deadly heat wave in May, and it covers only the 854 cities, which hold about 40% of Europe's population.

About one-third of the deaths came between June 17 and July 1, during an especially intense heat wave. Co-author Garyfallos Konstantinoudis, a biostatistician at Imperial College London, said temperatures in that stretch ran 9.5 degrees Fahrenheit (5.3 degrees Celsius) above normal. Italy, France, Spain and Germany recorded the highest death tolls, according to the study.

Lead author Clair Barnes, a climate scientist at Imperial College London, said some cities saw temperatures 21.6 F (12 C) warmer than normal this summer. She said Europe is the fastest-warming continent and is 4.5 F (2.5 C) hotter than in pre-industrial times, although the Arctic is warming faster still.

Who was most at risk

More than half of those who died were 85 or older, Konstantinoudis said. Younger adults were not spared: the heat also killed more than 800 people between the ages of 20 and 44.

How researchers arrived at the numbers

Heat deaths are underreported and often missing from death certificates, so the team relied on statistical modeling to establish the base count, Konstantinoudis said. The calculation draws on each city's age profile and on a local temperature at which the fewest deaths occur. Above or below that point, the model counts excess deaths.

To separate the role of climate change, the researchers simulated a world without it and compared those results with the deaths that actually occurred this summer. The gap between the two is the share attributed to global warming. Barnes said that share has grown from about 45% in the early 2000s to 65% now.

The team also checked its figures against real-time estimates from government agencies. They mostly matched, though not always, Konstantinoudis said. For the May and June heat waves in Britain, the model produced 2,700 excess deaths, while the United Kingdom's health statistics agency reported 2,800. Several outside experts, NPR reported, called the methods state-of-the-art.

Dr. Howard Frumkin, a former director of the National Center for Environmental Health in the U.S. who was not part of the study, said hotter summers and more accurate attribution tools are together producing higher and more reliable counts.

Why it matters: heat that infrastructure was not built for

Barnes said much of Western and Northern Europe has infrastructure that was not designed for the temperatures now being seen. In her view, the extra 2.5 degrees Celsius of warming can be what turns uncomfortable weather into dangerous, and potentially deadly, conditions for many people.

The findings point to a risk that reaches beyond the oldest residents and beyond any single country, since the highest tolls were spread across four of the continent's largest nations.

What experts say should happen next

Outside researchers who praised the study called for action on two fronts. Dr. Courtney Howard, a Canadian emergency room physician and president-elect of the Canadian Medical Association, urged urgent investment in heat early-warning systems, fair access to low-carbon cooling and neighborhood buddy systems that check on people at greatest risk, alongside rapid cuts in fossil fuel use.

Dr. Jonathan Patz of the University of Wisconsin-Madison, a professor of health and the environment, said adaptation alone is not enough. He argued that better cooling and protection for vulnerable groups must be paired with efforts to address the burning of fossil fuels at its root.

Around Prague, based on reporting by NPR