How to weather the deadly heatwaves?

Europe has been experiencing unprecedented heatwaves, resulting in thousands of deaths. As the health impact of heatwaves is yet to be fully ascertained and as climate-induced warming is expected to increase, urgent action is needed to mitigate climate change and adapt to its consequences.

Droughts and heatwaves in Europe, and floods in Pakistan – besides the war in Ukraine – dominated the headlines of Western media in 2022. 

As per a research report published on 10 July, there were 61,672 heat-related deaths in Europe in 2022, between 30 May and 4 September. The mortality rate was highest in Italy, Greece, Spain and Portugal.

Germany, the most populous country in the European Union, has faced a series of climate-induced catastrophes in recent consecutive years. While the disastrous flood of July 2021 claimed more than 180 lives and caused material damage worth billions of Euros, the heatwaves in 2022 resulted in around 4,500 deaths.

Human-induced global temperatures reached 1.1^oC above the levels of the pre-industrial period (1850-1900) in 2011-2020, as per the recent report by Intergovernmental Panel on Climate Change (IPCC). Since the climate-induced weather events are projected to increase, there is a need to strengthen adaptation measures.

Heatwave trends and human fatalities

IPCC has recently warned that heatwaves in Europe will be more intense, more frequent and will stay longer. It has indicated that by 2050, about half of the European population may be exposed to high or very high risk of heat stress during summer.

Claudia Winklmayr, a researcher at the Robert-Koch-Institute (RKI) within the Federal Ministry of Health, mentioned in an interview that RKI has a project focusing on calculating the number of heat-related deaths in Germany. The institute aims to improve its method and extend their research to obtain more detailed results.

According to RKI's research finding, the summer of 2022 was the fourth warmest since weather records began in 1881, and a significant number of heat-related deaths also occurred that year. The number of 4,500 heat-related deaths last summer is similar to the estimated heat-related deaths for the years 2015, 2019 and 2020.

On the difficulty of tracking climate change deaths, Winklmayr said, “We see an increase in the number of deaths during heatwaves in Germany, indicating a connection between high temperature and mortality. However, death statistics do not label any as a heat-related death.” 

“So, we need to use statistical methods to estimate the increase in number of deaths during hot periods. Basically we estimate the so-called baseline mortality, which represents the number of deaths that would have occurred without heatwaves. Then we compare the projected number with the observed number of deaths. The difference is attributed to heat,” she added.

In Germany, a web-based emergency service database, which includes emergency room (ER) visits and emergency calls, was used for real-time surveillance of heat-related morbidity in the city of Frankfurt am Main. Results from the summers of 2014–2018 show a consistent increase in emergency calls for heat-related diseases during heat wave periods, as per a report published by the WHO Regional Office for Europe.

Impact on health

Climate change can alter environmental factors, enabling vectors and pathogens spread into new areas and potentially increase the burden of communicable diseases, said Vladmir Kendrovski, Technical Officer for Climate Change and Health at WHO-European Centre for Environment and Health.

Winklmayr emphasised that the impact of climate change on health is a complicated topic and has not been extensively researched. “Studies show that people who died during hot periods are mostly elderly individuals aged 75 and above, with pre-existing conditions such as cardiovascular problems,” she said. 

Kendrovski highlighted that tens of thousands of people were forced to evacuate their homes due to raging wildfires fuelled by the heat in Europe. “The scale of the health impacts of heat depends on the intensity, timing and duration of a temperature event, as well as the level of acclimatisation and adaptability of the local population, infrastructure and institutions to the prevailing climate,” said Kendrovski.

Likely increase in risks

Since 1950, heatwaves have been increasing in frequency, absolute intensity and duration in southeastern Europe and Scandinavia, as per the WHO Europe report. The increase in number of hot days in most of southeastern Europe and Scandinavia per decade has been 10.

More temperature increases are expected in the northern part of the region during winter, as per the report. Urbanisation and higher population density exacerbate heat exposures and their impacts on health.

In the past 50 years, almost 150,000 people in the region lost their lives due to extreme temperatures. Kendrovski mentioned that although floods and storms accounted for a significant percentage of disasters (38% and 32% respectively), extreme temperatures were responsible for 93% of deaths. 

Even if global temperatures stabilise at 1.5°C above pre-industrial levels (the target of the Paris Climate Agreement), the number of people exposed to a present 50-year heatwave intensity in the European Union is expected to increase tenfold by the end of this century. 

Although RKI has not explicitly investigated the impact of climate change on health, they expect that the rise in temperature due to climate change, coupled with an aging population, will continue to lead to significant numbers of heat-related deaths in future.

“From our methodological models and diagnoses, we can see that in future, the number of deaths will increase. Therefore, we assume that some of these heat deaths might be related to climate change,” said Winklmayr.

Adaptation efforts 

Despite frequent extreme temperatures in the region, heat-related health impacts seem to be decreasing, highlighting the effectiveness of current adaptation measures. However, projections for the region indicate that without adequate adaptation efforts to climate change, heat-related exposures and health impacts could substantially increase. 

Kendrovski emphasised the importance of developing intersectoral mitigation plans so as to minimise future impacts. He mentioned the need for climate-resilient policies and practices that drastically reduce greenhouse gas emissions to effectively tackle global climate change.

To tackle heat-related health risks, local municipalities in Germany are taking proactive steps such as developing open spaces, educating vulnerable populations and implementing nature-based solutions. One of the solutions is the 'road tree concept’, which involves strategically planting trees along roads to create shade, mitigate heat island effects, enhance air quality and ultimately foster a livable city during heatwaves.