Europe's 2025 heat wave intensified by post-2015 emissions, study finds

A study published in Geophysical Research Letters indicates that emissions released in the decade following the 2015 Paris Agreement contributed significantly to the intensity of Europe's June 2025 heat wave. Using a diffusion-model version of generative AI trained on global climate models and historical weather data, researchers found a greater than 99% chance that post-2015 emissions made the event more severe.

In certain parts of Europe, these emissions increased average daily temperatures by approximately 0.3 degrees Celsius (roughly 0.6 degrees Fahrenheit). The research suggests that if emissions had been held at 2015 levels, the heat wave would have been measurably cooler. The study also noted that these post-2015 emissions have contributed to higher temperatures during Europe's hottest week of the year and an increase in extreme-heat days for every year since at least 2021.