Europe recorded its deadliest summer on record in 2026, with extreme heat contributing to more than 50,000 deaths across major towns and cities, while climate change was responsible for approximately 32,000 of the fatalities, according to a new scientific study.
The research, published in Nature Health, found that rising global temperatures significantly worsened the continent’s heatwaves, exposing millions of residents to dangerous conditions and placing growing pressure on public health systems.
Scientists from Imperial College London and the London School of Hygiene and Tropical Medicine assessed temperature and mortality data from 854 urban areas across the European Union, the United Kingdom, Norway and Switzerland. The locations covered approximately 40 per cent of the combined population.
Their findings showed that climate change contributed to about 65 per cent of the estimated heat-related deaths recorded during the summer. This represents a substantial increase from the beginning of the century, when global warming accounted for roughly 40 per cent of such fatalities.
The death toll also exceeded those recorded during previous devastating summers. Europe experienced an estimated 28,000 heat-related deaths in 2003 and approximately 29,000 in 2022, making the 2026 figures particularly alarming.
Italy recorded the highest number of deaths, with more than 13,000 fatalities linked to extreme heat. Although southern and western Europe experienced some of the most severe conditions, northern countries, including the UK, also suffered significant losses.
British urban areas recorded approximately 4,500 excess deaths during the summer, of which around 2,500 were attributed to heatwaves intensified by climate change. The country experienced several periods of extreme heat, including a late-June episode that prompted a rare red warning for life-threatening temperatures.
Between June 17 and July 1, temperatures across parts of Europe climbed more than five degrees Celsius above average. Researchers estimated that roughly one-third of the continent’s heat-related deaths occurred during this period alone.
While older people remain particularly vulnerable to extreme temperatures, the study estimated that approximately 6,000 people under the age of 65 died from heat-related causes across the urban areas examined. The figures highlight the danger heatwaves pose beyond traditionally recognised high-risk groups.
Dr Clair Barnes, a climate and extreme-weather researcher at Imperial College London, described the findings as evidence of the growing public-health consequences of increasingly hot summers. She called for targeted protection for vulnerable populations and a faster transition away from fossil fuels to limit further warming.
Dr Pierre Masselot of the London School of Hygiene and Tropical Medicine also warned that cities were not adequately prepared for rising temperatures. He identified expanded green spaces, reduced pollution and stronger healthcare support as important measures for reducing the risks.
Although the death toll was calculated using statistical modelling rather than a direct count of individual heat-related fatalities, the researchers pointed to previous estimates that closely matched official figures. An earlier assessment of the May and June heatwaves in England and Wales estimated more than 2,700 excess deaths, while subsequent figures from the UK Health Security Agency put the total at about 2,880.
Responding to the latest findings, Britain’s climate transition minister, Katie White, said the figures represented families who had lost loved ones during the summer. She said the government was working to prepare hospitals for extreme heat, expand clean energy and strengthen the country’s resilience to wildfires.
The study adds to mounting evidence that climate change is turning extreme heat into a major public-health threat. Researchers say improving urban infrastructure and reducing greenhouse gas emissions will be critical to preventing future summers from producing even higher death tolls.
