The summer of 2022 was the hottest in Europe since weather records began. Using statistical methods, a research team has now calculated that over 61,000 deaths across Europe were probably directly or indirectly attributable to the heat. In Germany alone there were more than 8,000 heat deaths. Older people in particular died, with women being more affected than men. From the researchers’ point of view, the results underline that current heat protection measures are not yet sufficient.
High temperatures pose a major health risk, especially for risk groups. The summer of 2022 was the warmest in Europe since weather records began and was accompanied by intense heat waves, extreme temperatures, droughts and fires. The European statistical office Eurostat reported a significant excess mortality for the summer months of 2022. So far, however, it was unclear what proportion of this is due to the heat. Because direct effects of the heat such as sunstroke or heat stroke rarely appear as a cause of death. Instead, it is mainly people with existing underlying diseases such as cardiovascular problems or lung diseases who die from the heat. However, her death certificate does not state the heat, but the underlying disease as the cause of death.
Many heat deaths also in Germany
To determine the number of heat-related deaths in Europe, a team led by Joan Ballester from the Institute for Global Health (ISGlobal) in Barcelona used temperature and mortality data from Europe for the period from 2015 to 2022 and created epidemiological models on this basis. These make it possible to determine the average number of deaths and the proportions of various causes of death. If the mortality data then deviate significantly from this average over a period of time, this can be an indication of excess mortality – an unusually large proportion of deaths that can be traced back to an influencing factor that only had an effect during this period. This enables an assignment even if this factor is not on the death certificate.
In total, data for 823 regions in 35 European countries with a total of more than 543 million inhabitants were included in the analysis.
The researchers come to the conclusion that between May 30 and September 4, 2022, an estimated 61,672 people in Europe died directly or indirectly as a result of the heat. As a result, 8,173 people died in Germany due to the extremely high temperatures this summer. This puts Germany in third place in terms of absolute heat-related mortality, behind Italy (18,010 deaths) and Spain (11,018 deaths). The highest mortality rates relative to population were in Italy (295 deaths per million), Greece (280 deaths per million), Spain (237 deaths per million) and Portugal (211 deaths per million).
Women over 80 most affected
The cause of this accumulation of heat deaths were the extreme conditions in the summer of 2022. Every single week in the period covered was warmer in 2022 than the average of previous years, as the team reports. The temperatures were particularly high in the week from July 18 to 24, 2022. According to calculations, 11,637 people died as a result of the heat in this week alone, in which the whole of Europe suffered from an intense heat wave. Overall, summer temperatures in Europe averaged 20.3 degrees Celsius, 1.68 degrees higher than the average for the years 1991 to 2020. The highest average temperatures were recorded in France at 2.43 degrees above the 1991 to 2020 average, followed by Switzerland (+2.30 °C), Italy (+2.28 °C), Hungary (+2.13 °C) and Spain (+2.11 °C).
Analysis by gender and age groups showed that people over 80 years of age were by far the most at risk from the heat. In this age group, more women than men died as a result of the heat. “Based on the population, we estimated the number of heat-related deaths in women to be 56 percent higher than in men,” the research team said. In contrast, more men than women died in the age group up to 79 years. “Prevention plans should also aim to reduce gender and age inequalities, as well as other factors that influence heat-related mortality risk,” write Ballester and his team.
Better prevention plans needed
Overall, the team came to the conclusion that the previous measures, especially to protect older people, were not sufficient. In the summer of 2022, almost as many people died across Europe as in the summer of 2003, which, with around 70,000 additional deaths, is the year with the highest heat-related mortality so far. “The summer of 2003 was an exceptionally rare phenomenon, even taking into account the anthropogenic warming observed up to then,” Ballester explains. The heat wave of 2003 caught European countries largely unprepared. At that time, the health systems were not prepared for climate-related emergencies, and prevention plans did not exist. In 2022, on the other hand, the heat was to be expected due to the trend of previous years, according to the researchers.
“The fact that more than 61,600 people died from heat stress in Europe in the summer of 2022, even though many countries already have active prevention plans in place compared to 2003, suggests that currently available adaptation strategies may still be inadequate,” says Ballester’s colleague Hicham Achebak. “The acceleration of warming observed over the past ten years underscores the urgent need to reassess and significantly strengthen prevention plans.”
Source: Joan Ballester (ISGlobal, Barcelona, Spain) et al., Nature Medicine, doi: 10.1038/s41591-023-02419-z