According to a new calculation, there were more than 60,000 heat-related deaths in Europe in the summer of 2022, the hottest summer on the continent since records began, reports a research team in the journal Nature Medicine. With 8,173 deaths, Germany had the third most victims, after Italy (18,010 deaths) and Spain (11,324 deaths). Calculated in relation to the number of inhabitants, there were 98 heat deaths per million inhabitants in this country, which puts Germany in 13th place among 35 European countries.
The group led by Joan Ballester from the Barcelona Institute for Global Health (ISGlobal) determined the values using data analysis and computer models. Heat-related deaths are not easy to record. Because heat as a direct cause of death, such as heat stroke or sunstroke, is rarely given – in this country in an average of only 19 cases per year, as the Federal Statistical Office (Destatis) recently announced.
Additional load
Therefore, physicians and statisticians rely on the evaluation of deaths and the comparison between hot and less hot summers. If more people die in weeks with high temperatures than in comparable weeks in other years, then this excess mortality is assumed to be heat-related. Although most of those who died from the heat died of a previous illness, the heat put an additional strain on the body.
Ballester and colleagues base their analysis on a large database: on more than 45 million deaths between January 2015 and November 2022 from 823 contiguous regions, representing over 543 million Europeans in 35 countries. The data comes from the Statistical Office of the European Union (Eurostat), supplemented with data from national statistical authorities. The researchers related the number of deaths to temperature anomalies, which were defined as the difference between measured temperatures and baseline temperatures. The base temperatures are mean values from the reference period 1991 to 2020.
Most were over 80 years old
According to the analysis, temperatures in Europe in June 2022 were between 0.78 and 2.33 degrees, in July between 0.18 and 3.56 degrees and in August between 0.91 and 2.67 degrees higher than the baseline temperatures. The highest temperature deviations were in Spain and southern France. With 237 heat deaths per million inhabitants, Spain is one of the most affected countries, along with Italy (295), Greece (280) and Portugal (211). France recorded the highest number of heat-related deaths among people aged up to 64 years (1007). Overall, France was more in the middle of the European range with 73 heat deaths per million inhabitants.
Where this data was available, the scientists assigned heat-related deaths to age groups. In the summer of 2022, 4,822 people aged up to 64 years died from heat, 9,226 aged 65 to 79 and 36,848 aged 80 or more. This confirms that heat is a particularly high risk for older people.
The Robert Koch Institute works with a different definition
The authors of the study urge politicians to act: “Given the extent of heat-related mortality on the continent, our results call for a reassessment and strengthening of heat monitoring platforms, prevention plans and long-term adaptation strategies.” If measures to adapt to climate change are not taken, the scientists expect a mean heat-related mortality burden of about 68,000 deaths per summer by 2030, more than 94,000 deaths by 2040, and well over 120,000 deaths by 2050.
According to Matthias an der Heiden from the Robert Koch Institute (RKI) in Berlin, the calculations of the study are on a solid basis. Nevertheless, he and colleagues have only identified 4,500 victims of the consequences of heat waves in Germany for the year 2022. He explains the difference to the 8173 heat-related deaths in the current study, among other things, with different definitions of “heat”: While Ballester’s team assumes a comfortable temperature (thermal optimum) with a weekly average of 17 to 19 degrees, this is in the RKI Study at 20 degrees.
“The study uses a broader concept of heat-related deaths,” says an der Heiden. “There is a weaker causal connection here.” In general, a distinction should be made between the effects of moderate and intense heat, the RKI numbers relate to intense heat. “There are different assessments of the question of whether moderate heat also has a causal effect on mortality.” In any case, the topic should be taken seriously, especially in countries with a rather moderate climate such as Germany. “In hotter countries, there is often more adaptation to high temperatures than in this country,” says an der Heiden.