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Nearly 600 heat-related deaths expected in UK heatwave, researchers estimate

21 Jun 2025 4 minute read
Heat wave – Image: Canva

Nearly 600 people in England and Wales are predicted to die as a result of this week’s heatwave, researchers have found.

Experts at the London School of Hygiene and Tropical Medicine (LSHTM) and Imperial College London used decades of UK data to predict excess mortality during the hot temperatures from Thursday to Sunday.

Their study, released on Saturday, forecasts that around 570 people will die because of the heat over the four days.

The excess deaths are estimated to peak at 266 on Saturday (June 21) when the heat will be at its most intense.

The researchers said their assessment highlights how extreme heat poses a growing threat to public health in the UK.

Climate change

It follows a World Weather Attribution (WWA) research group study published on Friday (June 20) which found the heatwave has been made about 100 times more likely and 2-4C hotter due to climate change.

Dr Garyfallos Konstantinoudis, lecturer at the Grantham Institute at Imperial College London, said: “Heatwaves are silent killers – people who lose their lives in them typically have pre-existing health conditions and rarely have heat listed as a contributing cause of death.

“This real-time analysis reveals the hidden toll of heatwaves and we want it to help raise the alarm.

“Heatwaves are an underappreciated threat in the UK and they’re becoming more dangerous with climate change.”

Deaths

Dr Konstantinoudis warned that people should follow heat-health advice this weekend and check on older people, particularly those living alone.

Temperatures had been forecast to hit 27C or more across parts of Wales on Saturday and had already reached 31C on Friday in Monmouth.

The researchers used findings from published research on the relationship between heat and the number of daily deaths, regardless of the cause, in 34,753 areas of England and Wales.

They combined these with high-resolution weather forecasts from the Copernicus climate change service to estimate how many heat-related deaths will occur.

They estimated that 114 excess deaths would have occurred on Thursday, 152 on Friday, 266 on Saturday and 37 deaths on Sunday, when temperatures will fall to the mid-20s.

People above 65 are expected to be hardest hit, with 488 of the estimated excess deaths, the report said.

But the experts also warn that heat can be life-threatening for all ages, with 82 deaths estimated for people aged under 65.

They also note that the analysis does not account for the effect of the heatwave occurring early in summer before people are acclimatised to hot temperatures, meaning deaths could be underestimated.

Warnings

A recent report by the UK Climate Change Commission estimated that heat-related deaths could rise to more than 10,000 in an average year by 2050 if fossil fuel burning causes warming to reach 2C.

UN scientists warned this week that the world is in “crunch time” to limit warming and has three years left to prevent global average temperature rises exceeding 1.5C.

Professor Antonio Gasparrini, of the LSHTM, said: “Increases of just a degree or two can be the difference between life and death.

“Every fraction of a degree of warming will cause more hospital admissions and heat deaths, putting more strain on the NHS.”

Dr Malcolm Mistry, assistant professor at the LSHTM, said: “Exposure to temperatures in the high 20s or low 30s may not seem dangerous, but they can be fatal, particularly for people aged over 65, infants, pregnant people and those with pre-existing health conditions.

“Unless effective mitigation and adaptive measures are put in place in the coming years, the risk of large heat-related death events is set to increase in the UK – we have a large ageing population and warming is expected to increase to 2C by 2050 and as high as 3C this century.”

Dr Lorna Powell, an NHS urgent care doctor in east London who was not involved in the study, said: “We are seeing cases of heat-related illnesses rising in our urgent care departments.

“Heat exhaustion can quickly trigger more serious illnesses as dehydration sets in and the cardiovascular system becomes overwhelmed.”


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Amir
Amir
26 days ago

Temperature fluctuations makes it harder to acclimatise and the concentration of heat is more intense in the cities than in suburban areas and the stated temperature figures are usually lower then the actual ones. This is only a situation then will worsen unless politicians really grasp the seriousness of climate change. We need to move quicker from fossil fuels and push renewables quicker. I strongly believe that fission nuclear is the wrong direction as we don’t have the capacity to store nuclear waste. Burning waste with gasification technology which does not happen anywhere in the UK. Solar panels only on… Read more »

Mab Meirion
Mab Meirion
26 days ago

Listen to them, a timely intervention from a GP surgery and local services rather than a blanket go to A+E which I’ve had for 5 years clog’s the system, GP’s know what I’m talking about…

The Covid Cowardice Clinical Tactics still taints some surgeries…

Jeff
Jeff
26 days ago

Meanwhile farage says sun never harmed anyone and UV is good for you and global warming is a myth/made up/stupid (delete as appropriate)

(I dunno if he said that but he said CO2 was safe).

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