Heat in Europe: who is most at risk?

Intro

Heat is the leading cause of weather- and climate-related deaths in Europe. Considering the consistent increase in global temperatures and extreme events such as heat waves, it is imperative to accelerate adaptation and support actions to prevent heat-related health impacts with a focus on protecting those most at risk.

Warming trends in Europe

Europe is warming twice as fast as the global average rate and faster than any other continent. According to the recent Copernicus 2024 State of climate report, the last 12 years have consecutively registered above average temperatures in Europe, with 2024 as the warmest year on record with +1.47°C above the 1991–2020 average. In 2024, 45% of days in Europe were much warmer (above 90°percentile 1991–2020 average) and around 12% of days were the warmest on record (Copernicus 2024). Summer 2025 was the fourth warmest summer on record in Europe, which was 0.9 °C warmer than the 1991–2020 average, with stronger warming in western and southern Europe (Copernicus, 2025). As climate change intensifies heat-related health impacts will increase substantially (IPCC, 2022, Vicedo-Cabrera et al.2018; Martínez-Solanas et al.2021) making it one of the greatest public health challenges of our time.

Who is most at risk?

Heat can affect everyone’s health; however, some people are more at risk due to individual (e.g. age, gender, health status) and contextual characteristics of where they live (e.g. climate, socio-economic conditions, built and living environment, access to health care). The effects of heat on health vary geographically between and within countries, regions and cities.

Evidence on vulnerable groups has been growing and become more consistent as reported by the WHO Europe updated evidence book on heat and health prevention (WHO EURO 2021). It is not just the elderly who are more at risk than the general population; other vulnerable groups include people with pre-existing chronic conditions (e.g. cardiovascular and respiratory diseases, endocrine system disorders, mental health illnesses, metabolic disorders and kidney diseases), pregnant women, small children, people living in socially and economically deprived environments, athletes, tourists and travelers, migrants and workers.

Workers and heat: an occupational health and safety issue

The 2024 International Labour organization report, showed that at least 2.41 billion workers – 71 % of the working population – are exposed to heat, resulting in 22.85 million injuries and 18,970 deaths annually (ILO2024). This means heat adaptation is not only a public health issue but also an occupational health and safety as well as economic resilience issue. The EU-OSHA published a guidance document of how to respond to Heat at work (EU OSHA, 2023) which focuses on the occupational setting and complements the WHO heat guidance (WHO EURO 2026).

Workers, especially those carrying out activities involving physical activity in sectors like agriculture and construction, are at greater risk of heat-related injuries or worsening of health status. Migrant and informal workers are mostly employed in manual and physically-demanding jobs, are more likely to have unstable contractual conditions and limited access to occupational health and safety training. A literature review, conducted as part of CATALYSE (Van Selm et al 2025), on migrant and ethnic minority outdoor workers found that around half (49%) of workers experience at least one heat-related illness and 28% reported at least 3 symptoms. Although workers reported hydrating frequently during work shifts, only a third reported modifying work schedule or tasks in response to heat and only 40% felt acclimatized at the beginning of the season. Workers reported working even in the heat due to fear of not being paid or pressure to maintain productivity. Overall, the findings highlight a critical need for enhanced occupational health and safety heat prevention measures and safety regulations for workers including migrants and informal workers.

Cost of heat in Europe

Out of the total EUR 822 billion losses in the EU member states due to climate and extreme weather events between 1980 to 2024, 18% were associated with heat waves (EEA, 2025). Economic losses have been increasing over time with a 54% increase from 2009 to 2024. Out of the fatalities related to climatic and meteorological hazards the vast majority (97%) were due to heatwaves.

Heat has significant implications on productivity and labour supply as well as economic activity and GDP per capita growth. The 2024 Europe Lancet Countdown report showed that an increase in temperatures in the period 1965-2000 resulted in a decline in the average number of working hours per person per year by 0.22% compared to 1965-1994. GDP per capita growth in southern Europe was 0.98% lower in 2020 due to higher (or lower) temperatures compared to 1981-2010 average (Van Daalen et al, 2024).

The 2021 EU Adaptation Strategy aims to build resilience and better manage climate risks to reduce monetary losses from weather- and climate-related events. Evaluating adaptation measures and quantifying the health-related economic losses and benefits is crucial to support decision makers and improve adaptation effectiveness; however data to carry out these assessments remains limited.

Heat-related deaths are largely preventable with adequate adaptation plans

The adverse health effects of heat are mostly preventable if adaptation and response actions are integrated in a heat–health action plan (HHAP), ideally developed through multi-sectorial collaboration. In 2008, the WHO Regional Office for Europe defined a HHAP guidance document outlining the 8 core elements a HHAP should have including identification of a lead body, heat warning alert systems, identification and care of vulnerable subgroups, preparedness of health and social care systems, long-term urban planning, reduction of indoor heat exposure, real-time health surveillance, monitoring and evaluation (WHO, 2008; WHO, 2021). Most recently, the WMO published a toolkit to support decision makers strengthen extreme heat risk governance (UNDRR, GHHIN, WMO , 2025).

Tracking the implementation of HHAPs in Europe is important to evaluate and monitor adaptation to heat. A survey carried out by the WHO in 2023, reported that 57% countries in the European Union (plus UK, North Macedonia and Switzerland) had a HHAP and warning system in place, while only 43% mention vulnerable groups in their Heat Plans (WHO, 2021; Sanchez- Martinez 2023). Adaptation measures included information campaigns on the health risks for each vulnerable group and recommendations on how to act duringheatwaves, training of health and social care staff on heat-related risks, opening cooling spaces and to a more limited extent active monitoring of vulnerable groups. In 2024, The International Association of National Public Health Institutions (IANPHI) carried out an additional survey addressed to national public health institutions addressing surveillance systems in HHAPs; 13 countries reported having heat -health surveillance systems in place, either for mortality or morbidity outcomes. Data from these surveillance systems are important to monitor health impacts and evaluate adaptation measures.

Is heat-related mortality changing in Europe in response to adaptation?

The association between heat and mortality changes over time based on variations in exposure, population characteristics and adaptation. Hence it is important to monitor how heat-related mortality risks change over time and evaluate the role of adaptation in reducing the impacts in terms of mortality burden.

A recent study conducted in Europe as part of the EARLY ADAPT and CATALYSE projects using weekly data (Gallo et al. 2023) showed what would have been the heat-related mortality if temperatures from the last two summers (2022 and 2023) had occurred at the beginning of the century with the societal vulnerabilities observed during the period 2000-2004. The maps show the change in vulnerability of the European population to heat and the consequent change in the heat-related mortality burden during the last two decades (2000-2023).

In 2022, heat-related mortality would have been 69% higher than what was observed if the population were the same as it was in the beginning of the century. Adaptation, considered as a reduction in heat-related mortality, was observed in most regions included in the study. In 2023, heat-related mortality would have been 80% higher in absence of adaptation in the last two decades. Regions in Spain and Portugal showed large reductions in heat-related mortality rates over time, while there was an increase in heat-related mortality in the Bulgarian regions.

Urban heat islands and heat adaptation in cities

The urban heat island (UHI) effect is when urban areas register higher temperatures compared to surrounding rural areas. The effect is attributable to several characteristics of the urban built environment. Generally, the larger the urban area and higher the population density, the stronger the UHI effect. Impervious surfaces like concrete and asphalt, low levels of vegetation and water bodies, and complex geometry due to buildings and other infrastructures all contribute to warmer temperatures in urban areas compared to their surroundings. UHI intensity is strongest at night due to lower winds and the release of heat radiation from built surfaces that have absorbed heat during the day. Urban residents are additionally exposed to heat compared to their rural counterparts

Rising temperatures due to climate change and the expansion of the urban built environment are expected to intensify UHIs and the adverse health effects related to heat in cities, making interventions to reduce the UHI effect increasingly important, particularly to protect vulnerable populations. Identifying hotspots within cities can help target interventions and emergency response as part of HHAPs. In addition to HHAPs, urban policy and planning can tackle UHIs and reduce heat exposure in cities by increasing green and blue spaces, unsealing built-up surfaces, and increasing the use of light colored (high albedo) materials that absorb less solar radiation compared to darker materials. Greener urban environments are not only good for heat adaptation, but also can reduce cooling-related energy demand and its associated greenhouse gas emissions. Urban green space also promotes health by reducing stress and providing opportunities for recreational physical activity.

UHI intensity at the ground surface varies across European cities depending on local climate, city size and urban characteristics. Maps show the average surface UHI in European cities in the period 2014-19. Adaptation can be assessed looking at changes in surface UHI intensity, increases in albedo or in green leaf area coverage (LAI). In the period 2014-19, a reduction in UHI in response to these factors was observed in 470 cities. On average, 11.4% of city areas had either an increase in albedo or green leaf area, resulting in an average reduction of surface UHI of 0.7°C.

Indoor heat guidance for workplaces in EU

In Europe, while most countries have basic requirements for workplace temperatures, specific maximum thresholds are less common, highlighting the need for tailored strategies to mitigate heat exposure and protect workers, especially in light of climate change and increasing heatwaves.

A review encompassing 38 EEA member countries, identified 53 pieces of legislation and 22 guidelines that addressed temperature conditions in various settings, including workplaces, healthcare, social care, and residential environments. The analysis found that a majority of existing legislation in Europe relates to general workplaces rather than specific settings, with commonly addressed environments including offices, construction sites, schools, care homes, manufacturing facilities, hospitals, hospitality venues, and agricultural sites. Various countries have set out temperature ranges that reflect the type of work activities being conducted, but they are limited and not widespread in their coverage. Thresholds for maximum indoor temperatures in workplace environments range from thresholds exceeding 24ºC to those surpassing 38ºC depending on the setting and country. For example, Madrid, Spain has guidelines for outdoor municipal workers to seek protection when outdoor daily average temperatures exceed 39C through modified work hours. Overall, legislation in Europe for maintaining safe and healthy indoor work environments is lacking and needs to be addressed to ensure workers and citizens in Europe are protected under current and future heat conditions.