The Guardian reported on Saturday that nearly 600 premature deaths are expected in England and Wales as a result of the ongoing heatwave, according to a rapid scientific analysis. Experts say this spike in mortality would not have occurred without the intensifying effects of human-driven climate change, which has raised current temperatures by 2°C to 4°C due to pollution from fossil fuels.

The forecasted deaths are concentrated largely in London and the West Midlands, with elderly populations being the most vulnerable. Researchers estimate that 85% of those who may die will be aged over 65, while people in densely populated inner-city areas face heightened risks.

Between 2020 and 2024, more than 10,000 people died prematurely during summer heatwaves, according to data from the UK Health Security Agency (UKHSA). In April, government efforts to protect public health from rising climate risks were sharply criticized by official advisers as "inadequate, piecemeal and disjointed."

Temperatures in the southeast of England are expected to reach 32°C on Saturday, a level scientists say has been made "100 times more likely" because of climate change.

"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," said Dr Garyfallos Konstantinoudis of Imperial College London, who participated in the analysis. "This real-time analysis reveals the hidden toll of heatwaves, and we want it to help raise the alarm," he added. "Heatwaves are an under-appreciated threat in the UK and they’re becoming more dangerous with climate change."

Fatal Degrees

Related News

Climate change caused 16,500 deaths in European cities in Summer 2025

Cutting air pollution could save 30,000 US lives by 2030

Prof Antonio Gasparrini of the London School of Hygiene & Tropical Medicine, another member of the research team, noted, "Increases of just a degree or two can be the difference between life and death. When temperatures push past the limits populations are acclimatised to, excess deaths can increase very rapidly. Every fraction of a degree of warming will cause more hospital admissions and heat deaths, putting more strain on the NHS."

Using decades of mortality and weather data across more than 34,000 locations, the team projected that about 570 people may die between Thursday and Sunday, including 129 in London alone. The researchers warned that this figure could be an underestimate, as people are typically less prepared for high temperatures in early summer.

"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," said Dr Malcolm Mistry at LSHTM.

Read more: World has 2 years of carbon budget to avoid breaching 1.5C target

Meanwhile, Londoners are also facing elevated levels of ozone pollution, prompting officials to advise those with lung conditions to avoid strenuous activity.

Global climate patterns are continuing to break records. The year 2024 saw the highest average global temperature on record, while carbon emissions from fossil fuels remain on the rise. If global temperatures climb 2°C above preindustrial levels, UK heat-related fatalities could exceed 10,000 annually by mid-century, according to the UK Climate Change Committee.

Nina Arquint, an executive at the insurance group Swiss Re, warned, "Extreme heat events are more dangerous than natural catastrophes in terms of human lives lost, yet the true cost is only starting to come to light." The firm estimates that globally, extreme heat claims around 500,000 lives each year—more than floods, earthquakes, and hurricanes combined.

Read more: A wasted planet gone on sale