More than 61,000 people died in last year’s brutal summer heatwaves across Europe, according to study released Monday in the journal Nature Medicine.
The findings suggest that two decades of efforts in Europe to adapt to a warmer world have failed to keep up with the pace of global warming.
“In an ideal society, no one should die from heat,” said Joan Ballester, a research professor at the Barcelona Institute for Global Health and lead author of the study.
This summer is likely to be even worse: In addition to climate change, the Earth entered a natural El Niño weather pattern during summer for the first time in four years, causing conditions that will increase the heat in many parts of the world. . The season is already shattering various global temperature records.
The researchers who studied last year’s heat waves used data collected by the European Union from 35 countries, including some non-member states.
Most of the people who died were women, especially those older than 80. Among younger people, men died at higher rates. Mediterranean countries, where temperatures were highest at the time, suffered the most: Italy, Spain and Portugal had the highest heat-related death rates.
Extreme heat was expected that summer based on how much the planet has warmed overall in the past decade, Dr. Ballester said. When temperatures rose, many European governments had “heat action plans” ready, developed in response to a more unexpected and deadlier heat wave in 2003, but those adaptations were not enough to prevent mass casualties, he said.
As climate change continues, the world can expect more and more deaths from extreme heat, Dr. Ballester added.
The statistical office of the European Union, Eurostat, regularly publishes the number of excess deaths (deaths above the expected average for a given time period) in European countries. Dr. Ballester and his colleagues took the official reports of total excess mortality from June to August 2022 and estimated how many of those deaths could be attributed to heat instead of other unusual factors like the coronavirus.
They used epidemiological models, meaning that they matched recent historical temperature trends in different regions of Europe with mortality trends during the same period, to establish numerical relationships between deaths and temperature changes in those areas.
“When there’s an up and down in temperature, we always see an up and down in mortality,” Dr. Ballester said.
The results of his team echo those of a study done shortly after the European heat wave in 2003, with some of the same collaborators. The earlier research found more than 70,000 excess deaths in Europe during the summer of 2003.
The previous study did not separate heat deaths from other excess deaths, so Dr. Ballester cautioned that the two numbers cannot be compared directly. The 2003 study also covered only 16 European countries, while the new study covers more than twice as many. When the researchers limited the results of this new modeling to those same 16 countries, they ended up with just over 51,000 heat deaths.
The researchers are working on applying the same epidemiological models to the 2003 heat wave to more accurately compare the two years. In addition to drastically different numbers after similar analysis, their results suggest that public policies adopted after 2003 have helped to slightly reduce the toll of extreme heat.
In France, the more than 10,000 additional deaths in the summer of 2003 had political consequences, including the resignation of the country’s director general for health. Over the past 20 years, officials there and elsewhere in Europe have invested in early warning systems for extreme heat, public cooling centers, volunteer forces to monitor older residents and better coordination between social services and hospitals.
But the changes across Europe were not enough. “It’s a spectrum” across different regions and populations, Dr. Ballester said.
Older people remain very vulnerable, especially those without access to air conditioning, as well as people who work outdoors. Older women were probably the worst off group last summer simply because they live longer than men at the ages when people are weakest and most likely to die during intense heat, Dr. Ballester said. He said other researchers have studied the reasons for demographic differences in death rates: For example, men tend to have worse health outcomes at younger ages, and some outdoor occupations, such as construction, are dominated by men.
This paper did not compare deaths between people of different races or ethnicities, but that is another important factor in vulnerability to heat, said Juan Declet-Barreto, a senior social scientist at the Union of Concerned Scientists, who studies the health effects of environmental hazards and was is not involved in this study. While Dr. Declet-Barreto is less familiar with the demographics in Europe, he said that in the United States, people who work outside and are more exposed to heat tend to be immigrants of color.
Eurostat does not have a breakdown of excess mortality data by race, ethnicity or immigration status, an agency representative wrote in an email. Dr. Ballester and his colleagues recommended in their paper that countries reporting to Eurostat better coordinate how they collect and share health data, including more demographic breakdowns. This year, the European Parliament proposed a regulation to do just that.
Even without additional demographic information, the study is “very timely” given this summer’s extreme heat, Dr. Declet-Barreto said. He thought the study’s methods seemed sound, because “there is a fairly well-known relationship in public health between heat and excess deaths.” He also agreed that comparing the 2022 and 2003 heat waves was helpful in revealing what health and policy interventions are still needed.
Four years ago, the International Federation of Red Cross and Red Crescent Societies published a guidebook to help city officials respond to heat waves, and its recommendations included changes to homes and physical infrastructure, such as improving energy efficiency and ventilation.
Dr. Declet-Barreto said he and other public health researchers have found that the most important factor in preventing deaths during heat waves is expanding access to air conditioning.