London heatwave killed 263 people – with climate change to blame for most, study says

An extra 263 people in London died during the recent heatwave, scientists have estimated, warning climate change has tripled the number of heat-related deaths across European cities.

Global warming, caused primarily by humans burning fossil fuels and cutting down forests, made the searing heat that gripped much of Europe in late June and early July much more intense, researchers found.

The heatwaves were up to 4C hotter across cities compared to a world without climate change, the study from the World Weather Attribution group of researchers said.

The first rapid study to estimate the number of deaths linked to climate change in a heatwave found human-driven global warming was responsible for around 65 per cent of the deaths that occurred across 12 cities, including London, Paris, Madrid, Barcelona and Rome.

The study found around 1,500 of the 2,300 estimated heat deaths were the result of climate change – equating to a tripling of the number of deaths in the heatwave due to global warming.

Last week, temperatures reached up to 34C in London, and an amber heat health warning was issued by the UK Health Security Agency.

The researchers from Imperial College London and the London School of Hygiene and Tropical Medicine (LSHTM) estimated there were 263 excess deaths in London due to the heatwave from 23 June to 2 July – 173 of these deaths were due to hotter temperatures because of climate change.

During these 10 days of warmth, a “heat dome” high pressure system over Europe trapped hot dry air and pushed up temperatures, as well as pulling hot air from North Africa, intensifying the heatwave.

The scientists behind the study warned heatwaves were “quietly devastating” and their research showed how dangerous climate change already was with just 1.3C of warming, particularly for older and more vulnerable people.

They also warned that their analysis focused on only 12 cities, providing only a snapshot of the deaths linked to climate change-driven high temperatures across Europe, which may have reached into the tens of thousands.

The researchers used weather data to assess the intensity of the heatwaves over their hottest five-day period in a world which has seen 1.3C of warming and compared it the cooler pre-industrial climate.

The analysis showed the heatwaves were around 1-4C higher than in a world which had not warned 1.3C due to climate change.

Climate change was responsible for an estimated, 317 excess deaths in Madrid and 235 in Paris, the study found.

Most of the deaths were in older age groups, the researchers said, highlighting the growing risk older people in Europe face from dying prematurely due to longer, hotter and more frequent heatwaves.