Europe's heat problem is more than rising temperatures

Europe’s heat problem is often described in terms of record temperatures. But the real story is broader than a series of hot summers. It involves the atmospheric patterns that can make heat persist, the health risks that follow, and how prepared our homes, cities, workplaces and public services are for a hotter climate.

Recent evidence makes the issue difficult to treat as a distant concern. The European State of the Climate 2025 report found that at least 95% of Europe experienced above-average annual temperatures in 2025. July saw a 25-day heatwave, and 41% of the continent experienced more days than average with at least strong heat stress.

But what is driving the pattern, and what does it mean for people?

Why European heatwaves deserve a closer look

A study published in Nature Communications in 2022 examined European heatwaves between 1979 and 2020. It found that heatwave days in Europe were increasing at around three times the rate seen across other northern mid-latitude regions. The trend in cumulative heatwave intensity was roughly four times faster.

The researchers linked much of the accelerated trend in western Europe to more frequent and persistent “double jet” states in the atmospheric circulation over Eurasia.

The jet stream is a fast-moving band of air high in the atmosphere. Its configuration influences weather systems, and persistent circulation patterns can help keep hot conditions over the same region. The study found that the persistence of double-jet states was associated with heatwave intensity, particularly in western Europe.

This is an important part of the explanation, but it needs to be read in context. The research analyses data only through 2020 and does not suggest that one atmospheric pattern explains every heatwave. It helps explain a particular regional trend over a defined period; it is not a complete account of climate change.

The health impact is not shared equally

Understanding the weather is one thing. Understanding who is exposed, and who can cope, is another.

The European Environment Agency’s 2022 report on climate change, health and well-being describes heat as the largest cause of deaths among weather- and climate-related events in Europe. It highlights that the risks are not distributed evenly.

Older people, those with existing health conditions, people on lower incomes, people living in homes that overheat, and people working outdoors or in hot environments can face greater risks. Cities can add another layer of exposure through the urban heat-island effect, where built-up areas retain more heat than their surroundings.

Buildings matter too. A home that is difficult to keep cool can turn a hot spell into a serious health risk, particularly for someone who is older, unwell or has limited options to go elsewhere. Workplaces, transport systems and healthcare services also need to function safely during prolonged heat.

The EEA report also discusses climate-sensitive infectious diseases, including dengue, malaria, West Nile virus and Vibrio. Climate change does not determine every outbreak, but it can alter the environmental conditions in which some disease vectors and pathogens thrive.

Newer evidence shows the scale of the challenge

The newer evidence reinforces the need to act, while also requiring care about what the numbers mean.

The 2026 Lancet Countdown in Europe report estimates that heat was associated with around 62,000 deaths in Europe in 2024. This is a model-based estimate, not a simple count of death certificates listing heat as the cause. Estimates can vary depending on the methods and geographic scope used.

A 2026 paper in Nature Health examined extreme heat-related mortality events across Europe. It estimated that a heat-related mortality event comparable to southern Europe's in 2022 has become many times more likely than it would have been in a pre-industrial climate, although with wide uncertainty around the exact figure. This is a comparison of how likely such an event is, not a statement that climate change caused a particular number of deaths, or that a particular fraction of all heat deaths can be assigned to climate change.

Meanwhile, the European State of the Climate 2025 report recorded widespread above-average temperatures and extensive heat stress across the continent.

No single statistic tells the whole story. Taken together, however, these sources point to a serious and continuing challenge for public health and infrastructure.

Adaptation needs to become practical

Reducing greenhouse-gas emissions remains essential. But mitigation alone cannot protect people from every heatwave that is already occurring or that is now unavoidable due to past emissions. Adaptation needs to move alongside it.

The EEA and WHO point to a range of practical responses, including:

• Heat-health action plans and warnings that reach people who are most at risk.
• Buildings designed or adapted for hotter conditions, balancing passive cooling, shading, ventilation, insulation and efficient mechanical cooling where appropriate.
• Urban planning and greening that can reduce heat exposure, while recognising that trees and green space need thoughtful placement and long-term maintenance.
• Workplace protections, including sensible scheduling, rest, hydration and controls for people working in hot conditions.
• Prepared health services with timely data and plans to respond to heat-related illness.
• Better surveillance and coordination, so that authorities can see where risks are growing and direct support accordingly.

These are not interchangeable interventions. What works best depends on the building, climate, local population and available resources. For example, mechanical cooling can reduce dangerous indoor temperatures, but it should be selected and operated with attention to energy demand, refrigerants, maintenance and the wider emissions picture.

Where data and technology can help

There is a role for data and technology, but it is worth being specific about the problem they are meant to solve.

Better local heat-risk information could help councils and health services identify neighbourhoods with high exposure. Building-level monitoring could reveal which homes or facilities overheat, while decision-support tools could help prioritise retrofits and support for vulnerable residents. Forecasting and alert systems can help services prepare before temperatures peak.

These tools are only useful if the information leads to action. Data that identifies a vulnerable household is not enough if there is no practical support available. An alert is not a solution if it does not reach the person who needs it. And a technology that reduces indoor heat should be assessed for affordability, energy use, reliability and maintenance, not just its performance on a specification sheet.

The challenge is therefore not simply to deploy more technology. It is to connect sound evidence, sensible design, public services and delivery.

The question is how quickly we act

The climate science and the health evidence are looking at different parts of the same problem. Atmospheric patterns help explain how heat can persist. Health research shows what prolonged heat means for people. More recent assessments indicate that the risks are already substantial.

Europe needs to keep reducing emissions while preparing its buildings, cities, workplaces and health services for hotter conditions. The most effective response will not come from one intervention or one technology. It will require a combination of planning, public health, engineering and targeted support for people who are most exposed.

Recognising the risk is the starting point. The harder task is turning that knowledge into practical action at the scale and speed required.

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References

1. Copernicus Climate Change Service / ECMWF (2026). “European State of the Climate 2025 report published.” https://www.ecmwf.int/en/about/media-centre/news/2026/european-state-climate-2025-report-published
2. Lancet Countdown in Europe (2026). 2026 report. https://lancetcountdown.org/europe/2026-report/
3. Lancet Countdown in Europe (2026). Associated academic paper. https://www.thelancet.com/journals/lanpub/article/PIIS2468-2667(26)00025-3/fulltext
4. Rousi, E. et al. (2022). “Accelerated western European heatwave trends linked to more-persistent double jets over Eurasia.” Nature Communications. https://doi.org/10.1038/s41467-022-31432-y
5. Beck, T. M., Gudmundsson, L., Schumacher, D. L. et al. (2026). “Extreme event attribution for heat-related mortality due to anthropogenic climate change across Europe.” Nature Health. https://doi.org/10.1038/s44360-026-00193-z
6. European Environment Agency (2022). Climate change as a threat to health and well-being in Europe: focus on heat and infectious diseases. https://doi.org/10.2800/67519
7. European Environment Agency. “The impacts of heat on health: surveillance and preparedness in Europe.” https://www.eea.europa.eu/en/analysis/publications/the-impacts-of-heat-on-health
8. World Health Organization. “Climate change: Heat and health.” https://www.who.int/news-room/fact-sheets/detail/climate-change-heat-and-health