Imperial College Study: 50,391 Deaths Attributed to European Summer Heat
Researchers found that human-caused warming contributed to nearly two-thirds of the excess fatalities across 854 cities.
By Petra Murphy ·
Researchers at Imperial College London have determined that extreme heat across Europe in the summer of 2026 resulted in 50,391 excess deaths. The study, set to appear in an upcoming issue of Nature Health, models mortality data from 854 cities during June, July, and August. The team calculated that 32,619 of these deaths were directly linked to the additional warming caused by the combustion of coal, oil, and gas.
The death toll for this summer is 71 per cent higher than the record set in 2022, when the same group counted 29,480 fatalities. Authors note that the current figures likely represent an underestimate because they exclude a deadly heat wave in May. Furthermore, the 854 cities in the study contain approximately 40 per cent of Europe's total population. Italy, France, Spain, and Germany recorded the highest numbers of heat-related deaths.
A concentrated period of high mortality occurred between June 17 and July 1, accounting for about one-third of the total deaths. During this window, temperatures were 5.3 C above normal, according to co-author Garyfallos Konstantinoudis, a biostatistician at Imperial College London. While more than half of the victims were aged 85 or older, the heat also claimed the lives of more than 800 people between the ages of 20 and 44.
Lead author Clair Barnes, a climate scientist at Imperial College London, noted that some cities experienced temperatures 12 C above normal. She stated that infrastructure in much of Western and Northern Europe is not designed to handle the temperatures resulting from human-caused warming. Barnes added that Europe is the fastest-warming continent and is now 2.5 C hotter than pre-industrial levels, a shift that can turn uncomfortable conditions into deadly ones.
To distinguish natural heat from climate-driven heat, the team used computer simulations to model a world without climate change. They compared these simulations with actual mortality data to determine the gap attributable to global warming. Barnes said the share of heat deaths linked to warming has increased from approximately 45 per cent in the early 2000s to 65 per cent currently.
The researchers used statistical modelling to account for age groups and each city's optimal temperature, where mortality is lowest. They validated their findings against government estimates, which largely aligned with their data. For the May and June heat waves in Britain, the model identified 2,700 excess deaths, while the UK's health statistics agency reported 2,800. Several outside experts described the methodology as state-of-the-art.
Dr. Howard Frumkin, former director of the National Center for Environmental Health in the U.S., observed that summers are becoming hotter while attribution tools are improving. He said these trends lead to higher and more reliable death counts. Outside experts emphasized that adaptation measures must accompany emission cuts. Dr. Courtney Howard, president-elect of the Canadian Medical Association, advocated for early-warning systems and equitable access to cooling. Dr. Jonathan Patz of the University of Wisconsin-Madison stated that society must address fossil fuel burning to stop the source of the problem.
The study concludes that the current heat mortality levels are a direct result of accumulated warming. The authors plan to publish the full findings in Nature Health. The data suggests that the gap between natural and climate-driven heat deaths is widening annually.
