July 9, 2025

expert reaction to ‘rapid heat death attribution study’ as released by Imperial’s Grantham Institute

Scientists comment on a heat-related death attribution study released by the Grantham Institute at Imperial College London. 

Dr Akshay Deoras, Research Scientist at the University of Reading, said:

“Robust techniques used in this study leave no doubt that climate change is already a deadly force in Europe. Think of the Earth like an oven. In the past, heatwaves were like turning the oven up for a short burst. But with climate change, it is as if we have permanently set the oven to a higher temperature. It takes much less to reach dangerous levels of heat that can be fatal.

“The June 2025 heatwave across parts of Europe and the UK was not simply a natural disaster—it was supercharged by fossil fuel emissions, costing countless lives in major cities. Heatwaves are now more frequent and intense because our planet’s baseline temperature is higher due to greenhouse gas emissions. Without urgent action to reduce fossil fuel emissions, these extreme heat events will become even more common and severe, putting greater pressure on health systems, disrupting daily life, and threatening the safety of communities across Europe.”

Prof Richard Allan, Professor of Climate Science at the University of Reading, said:

“A warming climate sure as hell makes heatwaves worse.  This forensic analysis combining observations, simulations and health data has shown how much more dangerous the recent European heatwave was across several cities with the higher levels of greenhouse gases in the atmosphere.  

“Even without these rapid attribution studies, it is blindingly obvious from the multiple lines of evidence that when weather conditions generate heatwaves, they are more intense, meaning that moderate heat becomes dangerous and record heat becomes unprecedented. The other side of the coin is that as one part of the globe bakes and burns, another region can suffer intense rainfall and catastrophic flooding as a warmer, thirstier atmosphere saps the moisture from one region and winds blow this excess moisture into storm systems elsewhere.  

“Communities need to adapt to an increasingly dangerous world through more resilient infrastructure and improved warning systems, yet it is only with rapid and massive cuts in greenhouse gases through collaboration across all sectors of society that worsening of weather extremes can be reined in.”

Dr Chloe Brimicombe, climate scientist at the Royal Meteorological Society, said:

“The study quickly shows how 65% of heatwave deaths in the last European heatwave can be linked to human-induced climate change in different cities. This is important because it shows that reducing emissions, which would stop an increase in heatwaves, could save lives. 

“We are facing more heatwaves this summer across Europe, with many regions also moving towards drought which increases heat and risk of wildfires increase too. We could see more deaths in heatwaves this summer. Research like this is important and being used more in climate litigation cases where groups take countries and companies to court over climate change. 

“It’s possible this study has even underestimated deaths slightly because it’s not taking into account the built environment and we know that often poorer parts of cities are more impacted because they are less “green” which means they heat up even more. 

“The results are a model summary of an increase in deaths over populations of cities during a heat period. But in reality the realisation of the risk of cardiac arrest is different to someone drowning. And that is why it’s important to issue heat warnings to everyone because there are a lot of different ways someone dies during a heatwave. 

“We need to talk about other heatwave impacts like pressure on transport, energy and food supplies. And we quickly need to think about how heat impacts economies as part of loss and damage. We also need to consider the rise in people attending hospital. We don’t really know enough about how heat impacts breastfeeding women and newborns, for example. 

“Heatwaves silently pressure our society. For some individuals this is now from before birth to the day they die.”

‘Climate change tripled heat-related deaths in early summer European Heatwave’ by Ben Clarke et al. is an unpublished ‘rapid heat death attribution study’ led by scientists at Imperial College London and the London School of Hygiene & Tropical Medicine.  The embargo lifted at 5am UK time on Wednesday 9 July 2025.

Declared interests

Richard Allan: “No conflicting interests”

Chloe Brimicombe: “No disclosures”

For all other experts, no reply for our request for DOIs was received.