Death by heat: study shows that rising temperatures are killing thousands while going unnoticed

 ROME - The summer heat caused by climate change was responsible for 68% of the 24,400 deaths that occurred between June and August in 854 European cities. This is 16,500 more deaths than would have occurred without a temperature increase of up to 3.6°C. While Italy was the most affected country, Milan was the worst affected city.

 The analysis was conducted by 11 researchers from Imperial College London, the London School of Hygiene & Tropical Medicine, the University of Bern, the Royal Netherlands Meteorological Institute and the University of Copenhagen. The results of the study, they warn, represent but a snapshot of the number of deaths linked to extreme heat, as the cities studied represent about 30%  of the European population. The analysis follows a study conducted by the same team, according to which climate change could have tripled the number of victims of a July heatwave in Europe.

 Italy had the highest number in Europe with an estimated 4,597 heat-related deaths, followed by 2,841 in Spain, 1,477 in Germany, 1,444 in France, 1,147 in the United Kingdom. The countries most affected by a single heatwave were Romania, Bulgaria, Greece and Cyprus from 21 to 27 July. As for cities, the impact of climate change on temperatures caused 1,156 deaths in Milan, 835 in Rome, 630 in Athens and Barcelona.

 Italy therefore ranks first, second, fifth and tenth in the list of 854 European cities analysed. The capitals with the highest per capita mortality rates were Rome, Athens and Bucharest, reflecting their exposure to some of the most extreme temperatures in Europe. However, researchers point out that other factors play a role, including preparedness, population demographics and air pollution.

 A silent (and underestimated) killer, with most heat-related deaths going unreported. People often die from pre-existing conditions, such as heart, respiratory or kidney problems, aggravated by high temperatures, and the role of heat is rarely recorded on death certificates. “The vast majority of heat-related deaths occur in homes and hospitals, where people with pre-existing health conditions are pushed to their limits, but heat is rarely mentioned on death certificates,” says Konstantinoudis Garyfallos, a lecturer at the Grantham Institute – Climate Change and the Environment at Imperial College London.

 Despite being the most lethal type of extreme weather, heat has long been underestimated as a public health risk. For example, even this summer in Europe, people continued to work outdoors in temperatures above 40°C. “No one would expect anyone to risk their life working in torrential rain or hurricane-force winds, but dangerous heat is still treated too casually,” he comments. To estimate the number of these deaths and how many were related to climate change, the study focused on the heat from June to August.

 First, scientists analysed meteorological observations and climate models to understand how climate change has affected daily temperatures in each city, finding that it has increased temperatures by an average of 2.2°C, but up to 3.6°C. Epidemiologists then used academic studies that predict changes in deaths at certain temperatures in 854 European cities. They combined these mortality risk functions with shifts in daily temperatures to estimate deaths due to heat this summer and a hypothetical cooler summer that had not been warmed by 1.3°C.

 The European population is ageing and summers will become increasingly deadly – “our study shows that variations in summer heat of just a few degrees can mean the difference between life and death for thousands of people,” comments Clair Barnes, a researcher at the Centre for Environmental Policy at Imperial College London.

 The analysis highlights how heat is a growing threat to Europe’s rapidly ageing population. People over the age of 65 account for about 85%  of total deaths, with 41%  over the age of 85, demonstrating how heat is particularly dangerous for people with pre-existing health conditions, such as heart disease and diabetes. The proportion of people over the age of 80 in Europe is expected to increase from around 6% today to 15% by 2100.

 According to the researchers, policies are needed to make cities more resilient to extreme heat. Around 70% of people in Europe live in cities, and this figure is expected to rise to over 80% by 2050. European cities can be on average 4–6 degrees Celsius warmer than rural areas, with peaks of up to 10 degrees, because concrete surfaces trap heat and transport and energy use further increase urban temperatures.

 However, researchers warn that “even with significant adaptation efforts, heat deaths will continue to rise until the world stops burning oil, gas and coal, which release emissions that trap heat and lead to hotter and more dangerous summers.”

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