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, new research shows09:09, 13 Jul 2026The recent heatwaves have killed more than 2,700 people, according to estimates from experts.‌Researchers have estimated that there were 2,700 excess deaths from heat-related causes during May and June’s two heatwaves.‌Scientists from Imperial College London, the Met Office, and the London School of Hygiene and Tropical Medicine (LSHTM) who conducted the research said that climate change played a big part in the increased death toll.‌Researchers found that more than two fifths (42%) died as a result of the extra heat caused by human activity – mostly burning fossil fuels.The peer-reviewed study looked at the time around the record-breaking heatwaves of May and June, when the mercury hit 35.1C and 37C respectively.‌The research looked at weather data, climate models and heat-related deaths research to estimate the number of people who died in the heatwaves - they then compared this to how many lives would have been lost in a climate that had not been warmed by human activities.According to the analysis, 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% of the deaths in May, some 327 people, and 38%, some 825 people, of those in June could be attributed to the extra heat caused by climate change, they found.‌Maximum daytime temperatures are around 3C-4C hotter than they would be without climate change, the researchers warned, meaning a greater risk of deaths from the heat.Risks of the higher temperatures include 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.“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.“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% 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.”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.”‌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.Article continues belowResponding 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.”