A new Stanford-led study used an AI diffusion model to isolate the impact of emissions released since the Paris Agreement. It found that post-2015 emissions added roughly 0.6°F to Europe's June 2025 heatwave, which killed thousands. The model also showed increased extreme-heat days across southern and eastern Europe since 2021. The research, published in Geophysical Research Letters, compared real weather patterns with counterfactual scenarios holding emissions at 2015 levels. Even a small share of cumulative fossil-fuel CO2, about 12.1%, measurably intensified the heatwave. The findings underline that climate pledges haven't stopped the damage from recent emissions, and every year of continued pollution adds to extreme heat risk.
