Extreme Heat and Wildfire Smoke Compound Public Health Risks in Europe

• Extreme heat is expected to remain Europe's largest climate-related public health threat.

• Heatwaves and wildfire smoke are likely to become recurring seasonal hazards.

• Older adults, young children, pregnant women, outdoor workers, and individuals with underlying conditions remain at greatest risk.  

• Healthcare systems are likely to face growing operational pressure during prolonged heat events.

• Many associated illnesses and deaths remain preventable through effective preparedness, early warning systems, and coordinated public health interventions.  

Extreme heat is contributing to excess mortality, exacerbation of chronic conditions, and increased pressure on health systems. Climate change is increasing the frequency, duration, and intensity of heatwaves, exposing larger populations to dangerous temperatures while reducing opportunities for overnight recovery through persistently high nighttime temperatures.  

Heat-related illness ranges from dehydration, heat cramps, and heat exhaustion to life-threatening heatstroke. However, the greatest health burden results from the worsening of existing medical conditions. Elevated temperatures place additional stress on the cardiovascular, respiratory, and renal systems, increasing the risk of heart attacks, strokes, asthma exacerbations, chronic obstructive pulmonary disease flare-ups, and complications among people with diabetes or other chronic conditions.  

The burden extends beyond direct illness and mortality. Heatwaves consistently increase ambulance callouts, emergency department visits, and hospital admissions. This surge in demand occurs while healthcare facilities may face increased electricity consumption, pressure on or failing of cooling systems, and heat stress and fatigue among healthcare workers.  

Although many European countries have implemented Heat Health Action Plans and early warning systems, preparedness remains uneven. Urban areas, communities with limited access to cooling, poorly insulated housing, and regions where infrastructure was designed for cooler climates remain particularly vulnerable during prolonged heat events.  

Wildfires are becoming more frequent and severe across Europe as rising temperatures, prolonged drought, and dry vegetation create increasingly favorable conditions for wildfires and fire spread. Although burns and direct fire impacts remain important, smoke exposure represents the principal public health consequence of large wildfires. Wildfire smoke contains numerous harmful pollutants, including fine particulate matter (PM2.5) and other toxic compounds.  

Exposure commonly causes eye and throat irritation, coughing, and shortness of breath. It can also worsen asthma and chronic lung disease and increase the risk of cardiovascular events, hospital admission, and premature death. Unlike the direct threat posed by flames, smoke frequently affects populations hundreds or even thousands of kilometers from active fires. Consequently, wildfire-related health impacts often extend well beyond evacuation zones, exposing millions of people to poor air quality.  

Wildfires and their resulting evacuations can disrupt access to healthcare, medicines, and essential services, while displacement and property loss contribute to substantial psychological distress. Firefighters and emergency responders face particularly high occupational risks through prolonged exposure to heat, smoke, dehydration, and psychological stress during extended response operations.  

The greatest public health challenge arises when extreme heat and wildfires occur simultaneously. Hot, dry conditions increase wildfire risk, while smoke further degrades air quality across large geographic areas. Together, these hazards can produce compounding health impacts that are greater than those associated with either event in isolation. Heat can cause dehydration, impair the body's ability to regulate temperature, and increase cardiovascular workload, while wildfire smoke can irritate the airways, worsen lung function in susceptible individuals, and trigger systemic inflammatory responses.  

These concurrent events also amplify operational pressures. Healthcare systems experience simultaneous increases in heat-related illness and smoke-related respiratory disease, while hospitals themselves may contend with overheating facilities, higher energy demand, and workforce fatigue. Disruptions to electricity, transport, water supply, and telecommunications may further complicate emergency response and access to healthcare.  

Although extreme heat and wildfire smoke affect entire populations, the burden falls disproportionately on vulnerable groups. Older adults face the highest risk because aging reduces the body's ability to regulate temperature, while chronic illnesses and certain medications further increase susceptibility. Other vulnerable groups include infants and young children, pregnant women, people with pre-existing conditions such as cardiovascular disease, respiratory illness, diabetes, kidney disease, or mental health conditions, and individuals taking medicines that affect hydration or temperature regulation.  

Occupational exposure is also significant for outdoor, construction, and agricultural workers, delivery personnel, firefighters, and emergency responders. Social conditions can further amplify risk; people experiencing homelessness, socially isolated older adults, migrants, lower-income households, and those living in poorly insulated housing without cooling may have fewer options to reduce exposure or access healthcare promptly.  

Extreme heat and wildfire smoke are expected to become increasingly frequent features of European summers as climate change drives higher temperatures, prolonged drought, and greater wildfire risk. Seasonal increases in heat-related illness, smoke-related respiratory disease, and excess mortality are therefore likely to become more common. Increased pressure on the healthcare infrastructure can also be expected.

The impacts will extend beyond healthcare. Heat and wildfires are likely to increasingly disrupt energy, water, transport, food systems, workplaces, schools, and other essential services, with cascading consequences for business continuity and emergency response. The greatest health impacts are likely in densely populated urban areas, regions experiencing persistent daytime and nighttime heat, and communities with older populations, high burdens of chronic disease, limited access to cooling, or inadequate heat-health preparedness.  

Although climate change will continue to increase long-term risk, many associated illnesses and deaths remain preventable. Continued investment in Heat Health Action Plans, early warning systems, wildfire preparedness, public risk communication, and climate adaptation measures will remain critical to reducing future health impacts and strengthening resilience. This represents the most complete data available as of July 29.  

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