Study ties post-Paris Agreement emissions to worse European heat waves

A massive heat dome is building across Europe as September draws to a close, delivering unseasonably high temperatures that forecasters expect to persist into early October — arriving just as a new study quantifies how greenhouse gas emissions released since the 2015 Paris Agreement have already made the continent's heat waves measurably worse.

Another Heat Dome Returns

The late-season heat event, driven by a blocking high-pressure ridge extending north from the Mediterranean and North Africa, is pushing temperature anomalies 8 to 12°C above long-term averages across western, central, and northern Europe. Temperatures in central and southern Spain and Portugal are forecast to exceed 35°C through the weekend, with peaks approaching 40°C in some areas. Southern and central France could see mid-30s, while northern France and the Benelux are expected to reach the low 30s.severe-weather

The pattern is expected to expand further into Scandinavia by early October, with the most anomalous warmth settling over Sweden and Finland. The heat dome marks the latest in a string of extreme heat events that have battered Europe throughout 2026, a summer that Deutsche Welle called the hottest on record for the continent. Germany alone recorded an estimated 16,300 heat-related deaths by the end of August, and provisional figures from Europe's EuroMOMO monitoring platform put continent-wide excess deaths above 30,000 during the summer's worst weeks.dw+2

Emissions Since Paris Agreement Made Heat Waves Worse

A study published September 22 in Geophysical Research Letters found that the greenhouse gases emitted in just the decade since the Paris Agreement was signed have intensified Europe's recent heat waves. Researchers at the Stanford Doerr School of Sustainability built a generative AI model trained on data from 10 global climate models to simulate how individual heat waves would have unfolded under lower, 2015-era emission levels.time+1

"We found that the emissions released since the signing of this Paris Agreement in 2015 have substantially and significantly increased the intensity of Europe's recent individual heat waves," said lead author Jared Trok, a PhD student in Earth system science at Stanford. The team estimated that the June 2025 heat wave was approximately 0.34°C warmer across Europe than it would have been without the post-2015 emissions.sciencemediacentre+1

That fraction of a degree carries outsized consequences. "There's a large body of scientific literature that suggests that even small increments of temperature on a hot day can have these disproportionate impacts on the damages caused by those heat waves," Trok said.time

A Warning Already Baked In

The study's co-author, Stanford professor Noah Diffenbaugh, emphasized that the climate effects of emissions already released are now locked in. "Even in the context of the most optimistic, ambitious future for reducing emissions, there's still more intensification of extremes that is essentially committed," he said. The Science Media Centre of Spain noted that the methodology could also open the door to legal claims for climate-related economic losses and deaths, by attributing specific extreme events to identifiable fractions of global emissions.sciencemediacentre+1