Nearly 600 people are expected to die prematurely across England and Wales due to the ongoing heatwave, according to a rapid scientific analysis that links the surge in heat-related deaths directly to human-driven climate change.
Researchers from Imperial College London and the London School of Hygiene & Tropical Medicine estimate that approximately 570 deaths will occur between Thursday and Sunday, with the highest tolls anticipated in London and the West Midlands. The findings reveal that 85% of these victims are likely to be over the age of 65, highlighting the vulnerability of older populations during extreme weather events.
The analysis shows that current temperatures in the UK have been made 2C to 4C hotter due to greenhouse gas emissions from burning fossil fuels, making extreme heatwaves such as this one significantly more deadly. In fact, scientists say that the 32C temperatures expected in southeast England on Saturday have been made 100 times more likely by climate change.
Heatwaves have claimed more than 10,000 lives across the UK between 2020 and 2024, according to the UK Health Security Agency (UKHSA). Yet, a report by official climate advisers in April criticised the government’s preparation and response as “inadequate, piecemeal and disjointed.”
“Heatwaves are silent killers,” said Dr Garyfallos Konstantinoudis of Imperial College London. “This real-time analysis reveals the hidden toll of heatwaves and we want it to help raise the alarm.”
Professor Antonio Gasparrini from LSHTM added, “Just a degree or two rise can push vulnerable populations beyond safe limits, increasing hospital admissions and fatalities rapidly.”
The data used by researchers mapped the correlation between temperature and mortality in over 34,000 local areas across England and Wales, supported by real-time weather forecasts. London alone is expected to see around 129 deaths in the current heat spell.
Dr Malcolm Mistry of LSHTM warned that even temperatures in the high 20s can be fatal, particularly for infants, the elderly, pregnant people, and those with existing health conditions.
UKHSA has issued an amber heat-health alert, which will remain in force until 9am on Monday. The alert warns of increased death rates and rising pressure on health and social care services.
The NHS is already seeing a rise in heat-related illness. “Heat exhaustion can quickly progress into serious health emergencies,” said Dr Lorna Powell, an urgent care doctor in east London.
Public health advice includes staying out of the sun between 11am and 3pm, staying hydrated, and checking on vulnerable individuals. A study also estimates that 80% of UK homes overheat during the summer months.
London faces additional danger on Saturday with a forecast of high ozone pollution levels, posing risks for people with respiratory conditions.
Experts emphasize that unless the UK drastically cuts carbon emissions, these events will only worsen. In 2024, the planet recorded its hottest year ever, with fossil fuel emissions continuing to rise.
By 2050, heat-related deaths in the UK could exceed 10,000 per year if global temperatures reach 2C above preindustrial levels, according to the UK Climate Change Committee.
Globally, extreme heat already claims more lives annually than floods, earthquakes, or hurricanes combined. Swiss Re, a major reinsurance company, estimates heat kills around 500,000 people each year.
“Extreme heat events are more dangerous than most natural catastrophes, and the human cost is only now becoming visible,” said Swiss Re’s Nina Arquint.
