Heat killed 'staggering' 50,000 people in Europe's cities this summer, scientists warn

Heat killed 'staggering' 50,000 people in Europe's cities this summer, scientists warn

Study estimates over 50,000 heat deaths across 854 European cities

Researchers from the London School of Hygiene & Tropical Medicine and Imperial College London published two peer-reviewed studies in Nature Health estimating that 50,391 people died from heat in 854 cities across 30 European countries between June and August 2026. The team compared actual temperatures in each city against those expected in a world without climate change, then applied peer-reviewed research linking high temperatures to daily mortality to model heat-related deaths. The method has been found to produce estimates broadly in line with those later produced by national health authorities.

Climate change drove nearly two-thirds of the deaths

Of the 50,391 deaths, 32,619 (about two-thirds, or 65%) are attributable to human-caused climate change, primarily from the burning of coal, oil and gas. Without global warming, the toll would have been around 18,000. That means climate change nearly tripled the death count. Researchers noted that an extra 2.5 degrees Celsius of warming from human activity is often enough to push temperatures from uncomfortable to dangerous and potentially deadly.

Toll 71% higher than previous deadliest summer

This summer's death count was 71% higher than the previous record of 29,480 deaths in 2022. The 2003 heat wave caused approximately 28,000 fatalities. The 32,619 climate-attributable deaths alone exceeded the entire heat-related mortality burden of either the 2003 or 2022 summer. Clair Barnes, a climate scientist at Imperial College London and lead author of both studies, said the summer of 2026 was likely the worst on record for heat-related mortality across much of Europe.

Italy hardest hit; southern and western Europe bore the highest rates

National tolls varied sharply. Italy recorded the highest at 13,303 deaths, followed by France with 7,268, Spain with 6,824 and Germany with 6,340. On an age-standardised basis, Malta saw 716 deaths per million, Italy 561 and Hungary 537, all well above the European average of 276 per million. Naples was the hardest-hit city on the continent at 815 deaths per million. Across 135 UK cities, an estimated 4,354 people died from heat, of whom 2,535 (59%) were linked to climate change, with an age-adjusted rate of 158 deaths per million.

Older adults most at risk, but younger people also died

More than half of those who died were aged 85 or older, but the stifling temperatures also killed more than 800 people between the ages of 20 and 44. An estimated 6,000 people under 65 died from extreme heat across the studied urban regions. In England and Wales, more than 2,700 excess deaths occurred during the record May and June heat waves, with the UK Health Security Agency later placing the actual toll at approximately 2,880. Urban areas in France recorded roughly 7,300 heat-related deaths over the whole summer.

One-third of deaths concentrated in two-week June-July heat wave

Deaths were heavily concentrated in time: almost one-third of the summer's total occurred between June 17 and July 1, when average temperatures across the studied cities were 5.3 degrees Celsius above normal. Heat waves struck repeatedly from late May through August. Raquel Nunes, an associate professor in health and environment at the University of Warwick who was not involved in the research, said the findings add to growing evidence of how deadly extreme heat can be, despite being described as a "silent killer" because its impacts are not always immediately visible.

Scientists warn European cities face a growing public health crisis

The researchers warned that Europe's cities are facing an increasingly severe heat health threat. Andrew Hartle, a professor of anesthesia at Imperial College London and intensive care consultant, said the estimated UK death toll of 4,500 serves as a warning that other areas with historically moderate climates need to prepare for extreme heat impacts now. The researchers emphasized that the temperature-mortality relationship varies by city, and the team calculated a localized optimal temperature for each city based on the fewest deaths, using that as a baseline to estimate excess mortality.