Ten days of extreme heat killed 2,305 people in a sample of 12 European cities last month, with almost two-thirds of those deaths caused by climate change’s intensifying effect on heatwaves, new research estimated on Wednesday.
The early summer heatwave, which sparked wildfires and health warnings from Spain to Turkey, was between 2 and 4 degrees Celsius hotter than it would have been without climate change, according to the study by the Grantham Institute at Imperial College London and the London School of Hygiene and Tropical Medicine (LSHTM).
“These numbers represent real people who have lost their lives in the last days due to the extreme heat”, said Imperial College London climate scientist Friederike Otto.
“If we continue to follow the wishes of the fossil fuel industry and delay serious mitigation [emissions-cutting] further, more and more people will lose their lives for the financial benefit of only a tiny rich influential minority,” she told reporters during a conference call.
Separately, a report by the European Union’s Copernicus Climate Change Service said last month was the hottest June on record in Western Europe.
Otto highlighted the researchers’ rapid work in calculating the role of climate change in the overall death toll, which she hailed as a first.
Rapid attribution study
Previously, such research has taken months. A study into Europe’s 2022 heatwave, which found that climate change was responsible for just over half of the 68,000 deaths, was published a year later.
The new study has not been peer-reviewed, a sometimes lengthy process where other scientists evaluate the research, Otto said, adding that the methods it used to attribute deaths had undergone peer review and been approved.
She said publishing studies quickly is important because the immediate aftermath of a heatwave is “when people talk about it”. That is also why the researchers focused on a sample of just 12 cities, she said, making their analysis more manageable.
Previous studies from the World Weather Attribution group, which Otto co-leads, have only estimated how much hotter climate change has made a heatwave. Otto said she wanted to translate this into numbers of additional deaths because a temperature increase of a few degrees Celsius “might not sound very much”.
Otto said the reason the first study like this was carried out in Europe is because scientists have established the relationship between heat and deaths better in Europe than elsewhere. But there are parts of southern Africa, Asia and the USA where this relationship has been established by scientists, she said, so “we will probably do this again in other parts of the world”.
But LSHTM climate professor Malcolm Mistry, warned that carrying out this kind of study across the world would be “very challenging because not every public health authority wants to give out the mortality record reports for research purposes”. This data on deaths is key to establishing how many people are killed by a certain increase in temperature.
Silent killer
The study did not attribute any individual death to climate change and heat is generally not listed on death certificates. Most people who died had health problems exacerbated by the heat, and more than half of them were aged over 85.
Heatwaves are a “silent killer” because the deaths mostly take place in homes and hospitals, away from public view, and are rarely reported, said Pierre Masselot from the LSHTM.
But media reports have blamed last month’s soaring temperatures in some specific cases, such as the death of 48-year old builder who collapsed while laying concrete in 35C heat in the Italian city of Bologna, and a 53-year old woman with a heart condition who died in Palermo. Climate Home has spoken to relatives of people who died during extreme heat in Saudi Arabia and the Gaza Strip.
Otto said that too many media reports about heatwaves include photographs of children eating ice cream and happy people playing on the beach. “That’s a massive problem”, she said, although she added that more articles were now referring to the role of climate change in driving heatwaves.
The researchers behind the study said ways to cope with extreme heat included installing air conditioning, improving government heatwave warnings, planting more trees, building more parks, insulating buildings and painting roofs white.
“But at the end of the day,” said Masselot, “all these measures won’t probably be as efficient as just reducing climate change altogether [by] reducing our greenhouse gas emissions.”
