Researchers estimate record heat toll

High temperatures contributed to an estimated 50,391 premature deaths in 854 cities across 30 European countries between the beginning of June and the end of August 2026, according to research by scientists from Imperial College London and the London School of Hygiene & Tropical Medicine reported by CNN and NOS. The cities account for about 40% of the combined population of the countries studied.

The researchers said the estimated toll was the highest in 26 years and concluded that the summer was likely Europe’s most dangerously hot to date. NOS reported comparison estimates of about 29,000 deaths for the summer of 2022 and 28,000 for 2003. Southern and western Europe were particularly affected, while northern areas including the UK were also estimated to have recorded thousands of deaths.

Climate attribution used a counterfactual model

The scientists modelled the overall toll using temperatures recorded in the cities and peer-reviewed research on the relationship between high temperatures and daily mortality. They then compared the recorded heat with temperatures expected in a world without human-driven climate change and applied the heat-mortality relationships to both sets of temperatures.

That analysis attributed more than 32,600 deaths—about two-thirds of the estimated total—to climate change driven by greenhouse gas emissions. CNN reported that the findings were published in two peer-reviewed papers in Nature Health.

Figures carry modelling uncertainty

The totals are statistical estimates rather than observed counts of deaths explicitly recorded as heat-related. The researchers said the method has previously produced estimates broadly consistent with figures later released by national health authorities. NOS also reported instances in which official excess-mortality figures were close to the study’s results, while noting differences in methods and periods covered.

Malcom Mistry of the London School of Hygiene & Tropical Medicine told NOS that heat deaths are underreported globally, and the researchers said the actual toll may therefore be higher. The highest estimated death rates were among people aged 85 or older, but the analysis also estimated about 6,000 deaths among people under 65, including more than 800 among those aged 20 to 44.