Heat in Germany: Health risks and preventive measures

Abstract

Background: Climate change has already led to a significant temperature increase in Germany. The average temperature in the past decade was approximately 2°C above the pre-industrial level and eight of the ten hottest summers since the beginning of systematic weather records in 1881 were recorded in the last 30 years.

Methods: Based on a selective literature search and authors' own results, the article summarises the current state of knowledge on heat and its health impacts for Germany, addresses adaptation measures, and gives an outlook on implementation and research questions.

Results: Heat can aggravate pre-existing conditions such as diseases of the cardiovascular system, the respiratory tract, or the kidneys and trigger potentially harmful side effects for numerous medications. A significant increase in mortality is regularly observed during heat events. Previous approaches to mitigate the health impact of high temperatures include, for example, the heat alerts of the German Meteorological Service and recommendations for the preparation of heat-health action plans.

Conclusions: Evidence on health impacts of heat and awareness of the need for heat-related health protection have grown in recent years, but there is still a need for further action and research.

Keywords: HEALTH PROTECTION; HEAT EVENTS; HEAT-HEALTH ACTION PLAN; MORBIDITY; MORTALITY; PREVENTION; VULNERABILITY.

Figure 1

Source: German Meteorological Service (DWD) Figure 1a (top) Change in the decadal means of the annual mean temperature over Germany between 1881 and 2020. Shown are anomalies of the decadal means relative to the mean of the period 1881 to 1910. Figure 1b (middle) Area means of hot days in Germany since 1951. Shown are decadal means, no area means for the number of hot days are available before 1951. Figure 1c (bottom) Regional distribution of the number of hot days per decade since 1951. Days in legend are rounded down to next integer.

Figure 2

Projected change of hot days and tropical nights (mean across Germany; in days) compared to the reference period (1971–2000) for the near and distant future using the RCP2.6 and RCP8.5 scenarios. The ensemble median and the range are shown. Source: Brienen et al. [11]

Figure 3

Mean number of heatwave days in the reference period 1981 to 2010 (left) and in the two emission scenarios RCP4.5 (moderate scenario) and RCP8.5 (business-as-usual scenario), each for the near and distant future. The boxplots show the interquartile range (IQR) as a box, the extent of the data as whiskers (lines with a maximum of 1.5*IQR) and outliers as points outside the whiskers. Source: Schlegel et al. [12]

Figure 4

Example of modelling heat-related deaths. The slightly increased total mortality in spring 2020 and the strongly increased total mortality in winter 2020/2021 are due to the first and second wave of the COVID-19 pandemic. Source: Adapted from Winklmayr et al. [14]

Figure 5

Exposure-response curves show the increase in weekly mortality as a function of the weekly mean temperature for four age groups (Example for greater region in Germany, period 2012–2021) Source: Own figure based on the modelling in Winklmayr et al. [14]

Figure 6

Direct and indirect effects of heat on health Source: Adapted from World Health Organization [35]

Figure 7

The eight core elements of a heat-health action plan with their temporal implementation: most core elements are implemented in each preparation and protection phase Source: Adapted from World Health Organization [63] and Straff et al. [64]

Figure 8

Established heat alert cascade in the pilot phase of the ‘Aktionsbündnis Hitzeschutz Berlin’ Source: Barker [84]