A distressing 2,700 people died from heat-related causes during May and June’s record hot spells in England and Wales alone as climate change makes heatwaves more deadly, experts estimate.

Researchers from Imperial College London, the Met Office and the London School of Hygiene and Tropical Medicine (LSHTM) estimated that there were at least 2,700 excess deaths in England and Wales over the two recent heatwaves.

And they found that climate change significantly drove up the death toll, as more than two fifths died as a result of the extra heat caused by human activity – mostly burning fossil fuels.

Temperatures

Their study, which used peer-reviewed methods to deliver near rapid estimates of deaths, examined the periods around the record-breaking heatwaves of May, when temperatures peaked at 35.1C, and June, which hit new highs for the month of above 37C, accompanied by high humidity.

The analysis used weather data, climate models and heat-related deaths research to estimate the number of people who died in the heatwaves, and compare it to how many lives would have been lost in a climate that had not been warmed by human activities.

The analysis found about 550 people are estimated to have died because of heat-related causes in nine days of the May heatwave, and about 2,200 in the 11 days around the June heatwave in England and Wales.

Around 59 per cent of the deaths in May, some 327 people, and 38 per cent, some 825 people, of those in June could be attributed to the extra heat caused by climate change, they found.

The researchers warn maximum daytime temperatures are around 3C-4C hotter than they would be without climate change, raising the risks from the heat.

Extreme

High temperatures are associated with risks including heat exhaustion, heat stroke, stress on the heart and kidneys and worsening chronic conditions such as heart disease, lung conditions and diabetes. They also worsen mental health, violence and increase the risk of death from drowning.

The Met Office’s Dr Mark McCarthy described the two record-breaking heatwaves as “exceptional”.

He said heatwave thresholds were rarely met in May, but this year daytime temperatures were widely 15C above the average for the month in England and Wales, while night-time temperature records were also set.

The June heatwave, which saw red warnings for extreme heat issued on consecutive days, was notable for its humidity as well as heat, he said.

“They were extreme heatwaves for the UK, and for all parts of western Europe, and they’re particularly exceptional for the timing and how early in the year they occurred.

Woke

“This combination of extreme daytime heat, high humidity and hot nights all act to really contribute and increase the impact these heatwaves have on our infrastructure, on transport, agriculture and particularly on our health and well being,” he said.

It was clear climate change is making heatwaves more frequent and intense, he said.

Dr Clair Barnes from Imperial College London, said heatwaves are the “most dangerous kind of extreme weather”, with the World Health Organisation recommending authorities in Europe plan for extreme heat in the same way they do for winter flu.

She warned that while heatwaves prompted news images of people eating ice cream and sunbathing on beaches, “people need to be aware that we are now seeing dangerous climate-change fuelled heat that is claiming lives, disrupting schools and hospitals and shutting down transport and infrastructure”.

“It’s time we woke up to the fact that we now live in a country with dangerously hot summers.

Mortality

“To protect people during future extremes, we must urgently adapt to the reality of the climate we now have, and double down on global efforts to reach net zero emissions to stop this from getting worse,” she said.

The independent advisory Climate Change Committee has warned that the UK is unprepared for extreme heat, which could see 92 per cent of homes overheating by mid century, and has called for maximum temperature rules in workplaces and air conditioning in hospitals, care homes and schools.

The UK Health Security Agency (UKHSA)’s Professor Lea Berrang Ford said the modelled estimates provided an important indication of the potential health impacts of sustained hot weather.

“While they are not a measure of observed mortality, they help illustrate the scale of risk associated with extreme heat and the growing threat climate change poses to our wellbeing.”

Action

The team behind the estimates said their models had produced mortality estimates comparable to those issued by the UKHSA for past heat events.

The UKHSA is due to publish its official interim analysis of heat-death impacts of the recent heatwaves, based on mortality data in the coming weeks.

Secretary of State for Energy Security and Net Zero, Ed Miliband, said: “The government will not leave our children and grandchildren to face the costs of climate breakdown and nature loss.

“That’s why we are working with others to drive action bringing energy security and lower bills, backing British businesses and creating good jobs, and protecting our home and countryside for future generations.”

Hydrated

Zack Polanski, leader of the Green Party of England and Wales, said: “These deaths are on the hands of politicians who have failed to act over the years. All those who put profit over the safety of the public by refusing to take real action to prevent the climate crisis – and are now failing to protect us from its impact.

“The message is clear: without action to protect people from extreme heat, we will see thousands more deaths in the years to come. Something must change.”

London Ambulance Service had the busiest week in its history during the June heatwave with a record number of life-threatening emergencies.

Responding to the analysis, the service urged Londoners to take simple steps such as avoiding excessive alcohol consumption to stay safe during the hot weather.

Alison Blakely, deputy chief paramedic, said: “As temperatures remain high, we would urge Londoners to take the heat seriously, stay hydrated and avoid strenuous activity such as running during the hottest parts of the day, as it puts extra strain on your heart and lungs.”

This Author

Emily Beament is the environment correspondent for the Press Association.