A new scientific analysis estimates that more than 50,000 people perished from high heat in cities across Europe in the summer of 2026, the deadliest summer for heat-related mortality in the continent in more than 20 years.
Conducted by researchers from Imperial College London and the London School of Hygiene and Tropical Medicine, the study predicted 50,391 heat-related deaths in 854 cities in 30 European nations between June and August.
They also assessed that 32,619 of the deaths, almost two-thirds of the total, were linked to human-caused climate change, primarily driven by greenhouse gas emissions from fossil fuel use.
The results are published in two peer-reviewed papers in the journal Nature Health. The scientists compared recorded temperatures with predictions of what temperatures would have been in a world without human-caused climate change, and then utilised proven correlations between temperature and mortality to determine the death toll.
Analysis estimates that the number of heat-related mortality was far more than that during the severe European heat waves in 2003 and 2022. Nearly a third of the deaths happened during a particularly hot week between June 17 and July 1.
Italy had the largest national toll estimated at 13,303, followed by France with 7,268, Spain with 6,824 and Germany with 6,340. The United Kingdom reported an estimated 4,354 deaths attributable to heat.
The researchers warned that while older individuals were the most vulnerable category, excessive heat also impacted younger people. It is believed that over 22,502 deaths were among those aged 85 years or over, but some 6,000 people under the age of 65 were also likely to have died from heat-related causes.
The findings underline how climate change is making worse the health consequences of protracted periods of excessive temperatures, researchers added. “Heat can cause dehydration, exacerbate underlying medical conditions and put extra pressure on health services, particularly if temperatures remain high overnight.
The findings also raise worries about the ability of European towns to safeguard inhabitants as heat waves intensify. Scientists have urged for improved heat warning systems, better access to cooling, more urban green spaces and tailored help for older people and other vulnerable individuals.
However, the researchers note that the data are estimated from models and do not directly count deaths officially documented. The investigation encompassed metropolitan regions which account for around 40% of the population in the countries studied, and hence does not fully reflect the impact of high heat across Europe.
The study adds to a growing body of science suggesting climate change is helping to create more deadly heat conditions. The key to minimising future heat mortality will be cutting greenhouse gas emissions and making cities better prepared for high temperatures, researchers say.
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