The study suggests that heatstroke deaths in Europe could triple by the end of the century, with the increase especially likely in southern European countries such as Italy, Greece and Spain.
Some have argued that climate change would benefit society by reducing deaths, as more people die from cold than heat in Europe, but the number of deaths could also rise as people respond more slowly to warming and become older and more vulnerable to dangerous temperatures, according to a study published in the Lancet Public Health journal.
The researchers concluded that if global warming reached a catastrophic 3 or 4 degrees Celsius, the increase in deaths from heatstroke would significantly outweigh the decrease in deaths from cold.
The researchers said their findings suggest that climate change could pose “unprecedented challenges” for public health systems, especially during heatwaves.
“As the climate gets warmer and the population gets older, we can expect to see more heat-related deaths, but only a slight decrease in cold-related deaths,” said study co-author David Garcia-León of the European Commission's Joint Research Centre.
If temperatures rise by 3 degrees Celsius above pre-industrial levels, warm weather deaths could reach 129,000 per year. Currently, heatstroke causes 44,000 deaths in Europe. But even if world leaders meet the 1.5 degree global warming target, the study found that annual deaths from cold and heat in Europe could rise from 407,000 today to 450,000 by 2100.
The study, which comes after a series of extreme heat waves that have caused devastation across the African continent, challenges claims made by climate change deniers that global warming is good for society because fewer people die from cold.
The study found that even in Europe, the coolest of the inhabited continents, the number of people killed by more intense heat would offset those saved by more moderate cold. Countries in Asia, Africa, Oceania and the Americas are hit by even more deadly heat.
“This study is a stark reminder of how many lives are at risk if we don't act fast enough on climate change,” said Madeleine Thomson, head of climate impacts and adaptation at health research charity Wellcome, who was not involved in the research.
Projections of a three-fold increase in direct deaths from heatstroke in Europe “don't even tell the whole picture,” she added, pointing to studies that have shown extreme heat leads to miscarriages and poor mental health. “And then there are the indirect effects. We're already seeing how extreme heat leads to crop failures, devastating wildfires, damage to critical infrastructure and hits economies. All of this will have a knock-on effect on our lives.”
The researchers modelled data from 854 cities to estimate heat- and cold-related deaths across the continent, and found that heat-related deaths will rise across Europe, but the heaviest burden will fall on southern European countries such as Spain, Italy, Greece and parts of France.
The researchers projected that a 3°C rise in global temperatures would lead to a 13.5% increase in deaths from uncomfortable temperatures, resulting in 55,000 deaths — slightly higher than the level of climate breakdown the policy is expected to cause. Most of the deaths would be in people over 85 years old.
Gary Konstantinoudis, an epidemiologist at the MRC Centre for Environmental Health, who was not involved in the study, said the research was of high quality and provided valuable insights, but warned that predicting temperature-related deaths was complex and always subject to uncertainty.
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The analysis was based on previous studies that assumed the effect of temperature on mortality remained constant from 2000 to 2019, but other studies have reported that mortality rates have fallen due to factors such as improved health care and changes in infrastructure, he said. “If we don't take this into account, we would expect to overestimate the future effect of heat on mortality,” he said.
The study extrapolated heatstroke mortality data to urban rural areas with less heat stress.
Elisa Gallo, an environmental epidemiologist at ISGlobal who has studied heatstroke mortality in Europe but was not involved in the new study, said adapting to rising temperatures was “becoming increasingly important”.
The researchers urged governments to consider policies to reduce the number of deaths, such as investing in hospitals, developing action plans and insulating buildings. They stressed that the predicted increase in deaths is driven by demographic and climate changes in Europe.
“If we want to avoid the worst-case scenario, it's essential that we address greenhouse gas emissions and get to the root of the problem,” Gallo said.
The researchers concluded that adaptation efforts should focus on areas with high rates of unemployment, poverty, economic change, migration and aging populations, which they said are less able to adapt to climate damage and will be hit harder by increased heatstroke deaths.
