Europe’s record-breaking June heatwave was made significantly more intense and far more likely by human-caused climate change, according to a new study (pdf) by the World Weather Attribution (WWA) consortium.
The researchers conclude that the heatwave, which they describe as the most severe ever recorded across the region analysed, would have been virtually impossible in the climate of 1976. Compared with the climate during Europe’s devastating 2003 heatwave, an event of similar intensity has become tens to hundreds of times more likely because of global warming.
June 2026 heatwave
The study was released as Europe continued to endure an exceptional early summer marked by two major heatwaves within weeks. Record temperatures disrupted transport, strained electricity grids, forced school closures and increased pressure on healthcare systems across several European countries.
Across France, Germany, Italy, Spain, southern England and other parts of Europe, temperatures rose far above seasonal norms as a persistent high-pressure system drew hot air north from North Africa. Clear skies and strong sunshine amplified the heat, while unusually warm nights limited recovery from daytime extremes and increased health risks.
A warmer climate, not different weather
According to the WWA analysis, a similar June heatwave today is about 3.5 °C hotter during the day than it would have been in 1976 and about 2 °C hotter than in 2003. Nighttime temperatures were estimated to be about 2.4 °C higher than in 1976 and 1.3 °C higher than in 2003.
The researchers also found that June heat extremes across much of Western Europe are increasing faster than average global temperatures. The hottest daytime temperatures are warming at roughly three times the rate of global warming, while the hottest nighttime temperatures are increasing at about twice the global average. June was identified as the fastest-warming month across much of the study region, helping explain why record-breaking heat is now occurring earlier in the summer.
One of the study’s central conclusions is that the weather pattern behind the heatwave was not unprecedented. The persistent high-pressure system, often described as a “heat dome“, resembled atmospheric circulation patterns seen during earlier European heatwaves. What has changed, the researchers said, is the climate baseline. The same type of weather pattern now produces much higher temperatures because the atmosphere is already warmer.
To estimate how global warming affected the event’s likelihood and intensity, researchers compared current temperature records with those from 2003 and 1976. The analysis focused on the hottest three consecutive days and nights across the most affected region and included 19 European capitals.
The researchers also assessed heat stress using Wet Bulb Globe Temperature (WBGT), which combines temperature and humidity to estimate how dangerous conditions are for the human body. Nearly 45% of the 854 European cities included in the analysis experienced record WBGT conditions during the June 18–29 heatwave, indicating unusually dangerous conditions for public health.
Growing health risks
Heat is Europe’s deadliest natural hazard, claiming more lives than floods, storms or wildfires. The report says ageing populations, chronic illness, urban heat islands and unequal access to cooling are increasing vulnerability as extreme heat becomes more frequent. Many homes, schools, hospitals, transport systems and energy networks were not designed for prolonged periods of extreme heat, leaving European cities increasingly exposed as temperatures rise.
The researchers caution that estimating the probability of events without close historical precedent carries uncertainty because they lie at the extreme edge of the observed record. Nevertheless, they conclude that the overall evidence shows human-induced warming has substantially increased both the likelihood and the intensity of extreme European heatwaves.
The study suggests that Europe does not need fundamentally different weather patterns to experience record-breaking heat. Instead, the researchers argue, decades of human-caused warming have made familiar atmospheric conditions capable of producing far more dangerous temperatures than they did only a few decades ago.
Journal Reference:
Keeping, T. et al., ‘Fossil fuel emissions have rapidly worsened European heatwaves in just a few decades’ (WWA scientific report No. 85), World Weather Attribution (2026). Download the full study (pdf).
Article Source:
Press Release/Material by World Weather Attribution (WWA)
Featured image credit: MAK | Unsplash
