LONDON (Reuters)

Heatwaves caused a record 2,556 excess deaths in Britain this summer as the country was struggling to contain the coronavirus pandemic, according to a government estimate published on Thursday.

Increasingly frequent and severe heatwaves are among the deadliest impacts of climate change, mostly hitting elderly people and other vulnerable groups the hardest, scientists say.

“Unless the government takes urgent action to address the climate emergency, the number of excess deaths due to heatwaves is likely to increase year on year,” said Sandy Robertson of the UK Health Alliance on Climate Change, an advocacy group of health professionals.

Britain suffered a series of heatwaves in June, July and August in which many weather stations around the country broke or matched their maximum temperature records.

The estimate of 2,556 excess deaths was the highest since the government launched a plan to manage the health effects of hot temperatures after an estimated 2,234 people died in England during a pan-European heatwave in 2003.

Researchers said high temperatures alone could not explain all the deaths, raising questions over whether the pandemic may have served to amplify the impact of the heat.

Some experts have questioned whether people might have hesitated to seek help for heat-related complaints for fear of catching COVID-19 in hospitals. The authors of the study said further research was needed.

Although scientists have yet to establish the role that climate change may have played in this year’s heatwaves, a previous study found that it had made a heatwave that hit Western Europe in 2019 at least 10 times more likely.

“Heat waves are the extreme weather events for which climate change is a real game-changer in most parts of the world, but particularly in Europe,” said Friederike Otto, a climate scientist at the University of Oxford.