Heat-related deaths in England and Wales could rise 50-fold by the 2070s as climate change collides with an ageing population, a study has warned.
It comes as areas of the UK face another heatwave, with temperatures over the next few days forecast to be above average and exceed 30C (86F) for many.
Annual heat-related deaths might climb into the tens of thousands in the coming decades, according to research by University College London (UCL) and the London School of Hygiene and Tropical Medicine.
They say today's baseline figure of 634 heat deaths a year could hit 10,317 in the 2050s and, in a worst-case scenario, 34,027 in the 2070s.
The prediction is based on 4.3C of warming and minimal efforts to adapt.
Older people are more vulnerable to extreme heat, and the research warns the population of England and Wales is expected to age significantly over the next five decades.
A more optimistic scenario - where the rise is only 1.6C from pre-industrial levels and major efforts are made to adapt - still envisages 3,007 deaths a year in the 2050s and 4,592 in the 2070s.
The experts want more action to adapt homes and cities.
Suggestions include better ventilation, increased air conditioning, shutters, urban forests, roofs that better reflect heat and more support for the vulnerable.
Researchers warn 2022's exceptionally hot summer - when it hit 40.3C (104F) and 2,985 excess heat-related deaths were recorded - could be the "new normal" by the 2050s.
"Over the next 50 years, the health impacts of a warming climate are going to be significant," said Dr Clare Heaviside from UCL.
"We can mitigate their severity by reducing greenhouse gas emissions and with carefully planned adaptations, but we have to start now."
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The study warns there could be between 21 to 32 extra hot days annually in the 2060s under scenarios with the least warming, and up to 64 to 73 in the most pessimistic case.
Commenting on the study, Dr Akshay Deoras, from the University of Reading, said: "If floods and storms are the loud alarms of climate change, extreme heat is its silent killer.
"It is disproportionately lethal, often going unnoticed until it's too late. With another heatwave bearing down on the UK, this warning feels more urgent than ever."
The study is published in science journal PLoS.
(c) Sky News 2025: Heat deaths in England and Wales could surge 50-fold by 2070s, study warns
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