Researchers modelling heat mortality across 854 European cities placed roughly 32,600 of the estimated 50,400 excess deaths recorded between June and August 2026 within the portion attributable to anthropogenic warming. The work was carried out by teams from Imperial College London and the London School of Hygiene & Tropical Medicine (LSHTM).
Ranging from 46,026 at the lower bound to 53,878 at the upper, the figures bracket a 95% empirical confidence interval around the aggregate death toll estimate. Between 26,078 and 38,237 deaths — accounting for 53% to 73% of the overall toll — have been linked to climate change's role in the event.
The figures represent statistically projected excess fatalities, drawn from modelling rather than from death certificates that formally attribute the cause to heat. Separating the influence of human-driven climate change from natural temperature variation, the team ran mortality projections against actual summer 2026 conditions and against a parallel scenario in which that anthropogenic warming had never occurred. Location-specific and age-stratified data on heat exposure and death rates were mapped onto each projected scenario, with the resulting difference between those two estimates treated as the portion attributable to a shifting climate.
Spread across 30 countries — the 27 EU member states alongside the United Kingdom, Norway, and Switzerland — those 854 urban areas fall within this combined geographic footprint. Taken together, those nations account for around 172.7 million people — a share that works out to roughly four in every ten residents across the full group of 30 countries. According to the document, city-based data drawn from that sample cannot be extrapolated into a continent-wide figure.
Among the age brackets examined, those 85 and older accounted for an estimated 22,502 deaths — a figure representing roughly 45 percent of the total produced by the model. Among adults in the 20-to-44 age bracket, the death toll was placed at roughly 833 by those conducting the research.
Among world regions, deaths linked to heat fell most heavily on Southern Europe. Among the four nations carrying the heaviest projected death tolls, Italy recorded an estimated 13,303 fatalities, while France accounted for 7,268, Spain for 6,824, and Germany for 6,340.
Roughly a third of all projected summer fatalities fell within the two-week window running from June 17 through July 1. Measured against the 1991–2020 baseline, those two weeks saw each city's mean daily temperature run 5.3°C warmer than the long-term norm.
Across those same urban areas, the study put heat-attributable excess mortality at roughly 29,480 for 2022 and approximately 28,462 for the year 2003.
Masselot, an LSHTM statistician and epidemiologist holding an assistant professorship, noted that urban environments have shown mounting evidence of inadequate adaptation to hotter temperatures. The research team called for action on both emissions reductions and local-level protections — among them heat alert systems, improved readiness in homes and healthcare settings, and wider provision of shaded areas and green space. The elevated heat risk, according to LSHTM's findings, traces back to warming driven by greenhouse gas output — chiefly the burning of fossil fuels.
