Emissions released since the Paris Agreement have intensified recent heatwaves in Europe

The study adds a further assessment which highlights the growing body of evidence that there is a close link between the continued rise in global emissions and the intensification of summer heatwaves in Europe between 2021 and 2025. They even provide a quantification: they estimate that the June 2025 heatwave was approximately 0.34 °C warmer across Europe than it would have been without emissions. To achieve this, they use generative artificial intelligence to overcome some of the limitations of extreme event attribution to date. However, there are significant limitations that must be taken into account, such as statistical robustness for small spatial scales (~250 km – which, in practice, are not so small for some extreme events) compared with the regional average (~2,500 km), and the exclusion of land-use or aerosol forcings.

As for the implications, the results indicate that pollution emitted in the last decade alone is already having a direct and measurable impact on the scale of current climate-related disasters. This reinforces existing studies and underlines the unavoidable and urgent need to reduce emissions and even the concentrations of greenhouse gases already present in our atmosphere.

The science of attributing the influence of climate change to individual weather extremes is advancing very rapidly. This study, through the use of artificial intelligence, has developed a much faster method for making this attribution compared with the more common method of analysing the results of large climate models with and without the actual accumulation of greenhouse gases in the atmosphere.

This new study, which focuses on the impacts of emissions since the Paris Agreement was adopted in 2015, shows that even emissions from the last 10 years alone have already had a clear effect on heatwaves in Europe since 2021, including the most recent ones, which have been more intense and longer-lasting.

These findings serve as an alarming reminder that the vast quantities of greenhouse gas (GHG) emissions we are producing have continued to rise globally since we committed to stabilising the climate under the Paris Agreement. The study is yet another call from the scientific community to accelerate the decarbonisation of our economies at a much faster pace than at present.

In this article, scientists at Stanford have succeeded in measuring, to a significant degree, how emissions over a very short period exacerbate a specific extreme event. Until now, this had been difficult due to computational limitations and the natural variability of the climate.

Using generative AI models, they analysed a specific scenario: “What would the European heatwave of June 2025 have been like if we had frozen emissions in 2015, in line with the Paris Agreement?” 

Emissions released between 2015 and 2025 made that heatwave ~0.34 °C more intense. 

They also state that being able to attribute an event to specific fractions of emissions (with a minimum of 12 per cent of global emissions required to separate the signal from the noise) paves the way for direct legal claims for economic losses and deaths, and for seeking scientifically grounded compensation.