Climate change tripled death toll from European heatwaves this summer, study says

Climate change intensified temperatures across Europe this summer, leading to an additional 16,500 deaths, according to leading climate scientists and epidemiologists.

In a new study, experts looked at 854 European cities and found that climate change was responsible for 68 per cent of the 24,400 estimated heat deaths this summer, increasing temperatures by up to 3.6°C.

Researchers at Imperial College London and the London School of Hygiene & Tropical Medicine, who led the analysis, warn that this is only a snapshot of the true death toll. The cities studied represent just 30 per cent of Europe’s population. 

The analysis follows a study released earlier this year from the same team, which found that climate change could have tripled the death toll from Europe’s July heatwave. 

Where in Europe was climate change behind the most heat deaths?

The countries hardest hit by a single heatwave were Romania, Bulgaria, Greece and Cyprus, where from 21 to 27 July an estimated 950 heat deaths occurred in temperatures up to 6°C above average. That is around 11 daily deaths per million people. 

The European capital cities which saw the most deaths per capita were Rome, Athens and Bucharest. The study’s authors say it reflects their exposure to some of the most extreme heat in Europe, but they point out that other factors also play a role, including preparedness, population demographics and air pollution. 

Across all 854 cities, climate change was behind 4,597 estimated heat deaths in Italy - the highest overall total. It was also behind 2,841 deaths in Spain, 1,477 in Germany, 1,444 in France, 1,147 in the UK, 1,064 in Romania, 808 in Greece, 552 in Bulgaria and 268 in Croatia. 

Heatwaves are ‘silent killers’

Deaths from extreme heat made the headlines this summer, including Montse Aguilar, a 51-year-old street cleaner in Barcelona, Spain and Brahim Ait El Hajjam, a 47-year-old construction worker in San Lazarro di Savena, Italy. But the vast majority of heat-related deaths go unreported. 

People often die from underlying health conditions such as heart, respiratory or kidney problems made worse by high temperatures.

“Heatwaves are silent killers. The vast majority of heat deaths happen in homes and hospitals, where people with existing health conditions are pushed to their limit, but heat is rarely mentioned on death certificates,” explains Dr Garyfallos Konstantinoudis, lecturer at Imperial College London’s Grantham Institute – Climate Change and the Environment.

“Despite being the deadliest type of extreme weather, heat has long been underestimated as a public health risk.”

Dr Akshay Deoras, a research Scientist at the National Centre for Atmospheric Science, University of Reading, who wasn’t involved in the study, says the research also highlights that “heat does not kill equally”.

“Older populations are affected the most, with more than 80 per cent of the excess heat-related deaths occurring among people aged over 65.”

People over 85 made up more than 40 per cent of the total deaths, and those over the age of 80 are expected to make up 15 per cent of Europe’s population by 2100. Europe is the world’s fastest-warming continent, and heat is a rising threat to its rapidly ageing population.

Even a few degrees can cause large surges in deaths when vulnerable populations are exposed to temperatures beyond the limits they are used to dealing with.

“While today's emissions continue to rise, it is the older generation, many already in fragile health, who are paying the highest price for our collective inaction,” Dr Deoras adds.

A few degrees can be the difference between life and death

Climate scientists first looked at how climate change had influenced daily temperatures in each city. They found that climate change, caused primarily by the burning of fossil fuels and deforestation, had increased temperatures by up to 3.6°C. 

Epidemiologists then looked at previous research showing how the number of deaths changes with temperature in 854 European cities. They used it to estimate how many people had died from heat across the continent this summer and how many people would have died if the summer hadn’t been heated by 1.3°C.

The study estimates that around 24,400 people died as a result of extreme temperatures in these cities. But without warming caused by human activities, 16,500 of these deaths could have been avoided, meaning climate change was responsible for 68 per cent of the excess deaths. It tripled the potential death toll.  

“It may not sound like much, but our study shows that shifts in summer heat of just a few degrees can be the difference between life and death for thousands of people,” says Dr Clair Barnes, researcher at Imperial College London’s Centre for Environmental Policy. 

“It is another reminder that climate change isn’t an issue we can just deal with at some point in the future.”

The health burden from heat in Europe has stayed high

Around 70 per cent of people in Europe live in cities, with that proportion expected to rise to 80 per cent by 2050. Urban areas can be up to 10°C hotter than rural areas because of something known as the urban heat island effect. 

Policies to adapt to heat, like flexible work schedules, adjusting the school calendar or increasing urban green spaces - cooler areas that can be a lifeline for lower-income communities that live in hotter, denser housing - could improve well-being and save lives. 

“Heat-health warning systems and action plans are actually well-developed across most regions in Europe,” explains Dr Malcolm Mistry, Assistant Professor at the London School of Hygiene & Tropical Medicine.

“However, even with warnings issued by meteorological and public health authorities across Europe, the health burden associated with heat has remained consistently high in recent summers.”

The researchers warn that even with major adaptation efforts, heat deaths will continue to rise as greenhouse gas emissions trap heat and lead to hotter, more dangerous summers. 

The “harsh reality” is, Dr Mistry adds, that unless we urgently reduce greenhouse gas emissions, adaptation efforts are going to play a limited role in mitigating the risks of human-caused global warming.