UK and European heatwave 2025

This briefing paper has also been published as a webpage: UK and European heatwave 2025

This background briefing was written by:

• Jenny Bird, Campaign Manager, Grantham Institute, Imperial College London
• Dr Ben Clarke, Research Associate, Centre for Environmental Policy, Imperial College London
• Dr Garyfallos Konstantinoudis, Lecturer, Grantham Institute, Imperial College London
• Dr Frederike Otto, Associate Professor, Centre for Environmental Policy, Imperial College London.

It was reviewed by Dr Caterina Brandmayr, Grantham Institute, Imperial College London and Dr Neil Jennings, Grantham Institute, Imperial College London

Media enquiries: grantham.media@imperial.ac.uk
Policy enquiries: j.bird@imperial.ac.uk  

This background briefing covers evidence on the heatwave that affected the UK and Europe in June-July 2025. It also shares evidence on the impact of climate change on heatwaves, how heatwaves affect the economy, public attitudes towards heatwaves and what is being done to protect people in the UK.

Key points

• It is estimated that the June-July 2025 heatwave in London will have resulted in around 260 heat-related deaths. Of these around 170, or 65%, can be attributed to climate change, meaning the death toll was tripled due to climate change.
• Heatwaves also have an impact on the economy – reducing productivity and increasing costs to the NHS.
• Climate change means heatwaves like this are now expected to occur every 6 years in London. Without climate change, we would have only expected such an event once every 60 years at most.
• Adaptation to manage urban heat risk is essential to deal with climate impacts that are now locked in because of historic greenhouse gas emissions.
• Heatwave temperatures will keep rising and future death tolls are likely to be higher, until the world largely stops burning oil, gas and coal and reaches net zero emissions.