From Wildfires to GDP Losses: Why Madeleine Thomson Says Europe’s Heat Is a Health Emergency

In Spain’s Galicia region this August, smoke hung over hillsides as firefighters battled flames fanned by hot, dry winds. In southern France, red alerts forced tens of thousands to evacuate. Across Europe, the summer of 2025 has been defined by fire and heat — a pairing that scientists warn will only become more frequent.

For Madeleine Thomson, Head of Impacts and Adaptation at Wellcome, the lesson is stark: extreme heat is not only an environmental or economic challenge. It is, above all, a public-health emergency.

Fires and Fatalities

The scale of destruction is already historic. By mid-August, about 400,000 hectares had burned across Europe, an 87 percent increase over the 20-year average. Spain has borne the brunt, with 158,000 hectares lost and 2,000 additional troops deployed to reinforce firefighting crews.

The fires have claimed at least six lives, including two firefighters, and displaced tens of thousands. But the greater mortality toll comes not from flames, but from the heat itself. A rapid analysis by Imperial College London and the London School of Hygiene & Tropical Medicine estimated that a 10-day heatwave in late June and early July killed around 2,300 people across 12 European cities, with about 1,500 deaths attributable to climate change that intensified the event.

Economics on Fire

The heat crisis also carries a steep economic price tag. Allianz Research estimates that Europe’s 2025 heatwaves may cut GDP by 0.5 percentage points, with Spain’s output dropping by up to 1.4 points as outdoor labor productivity collapses and energy systems strain under peak demand.

For Thomson, the connection between economic losses and health outcomes is straightforward: when people can’t work safely, when hospitals are overwhelmed, and when communities are displaced, the economy suffers too.

Thomson’s Perspective

Thomson’s authority comes from decades spent at the interface of climate science and health. At Columbia University’s International Research Institute for Climate and Society, she directed the WHO Collaborating Centre on Malaria Early Warning Systems, pioneering methods that used rainfall and temperature forecasts to predict outbreaks. She later served as a Senior Research Scholar at Columbia’s Mailman School of Public Health, focusing on climate-sensitive diseases and hydrometeorological disasters.

Now at Wellcome, she leads the foundation’s push to put climate at the heart of health research and policy. Wellcome’s Climate and Health programme funds projects that develop early-warning systems, assess the nutritional consequences of climate change, and test interventions that protect vulnerable populations.

Her consistent message is that adaptation must be data-driven and proactive. “Extreme heat doesn’t just cause fatalities — it increases the risk of heart disease, pregnancy complications, and poor mental health,” she told Sky News in April.

What Needs to Change

Europe’s summer of fire and heat has revealed gaps that Thomson and other experts say must be closed:

- Integrate climate and health data. At a World Meteorological Organization meeting in 2024, Thomson urged governments to merge climate forecasting with health surveillance: “We can’t do climate and health without the climate… We can no longer afford to be flying blind.” Tools like the WHO–WMO ClimaHealth portal now provide case studies and resources to help countries operationalize that integration.
 

- Account for night-time risk. “Tropical nights,” when temperatures never fall below 20°C, are increasing rapidly. By preventing recovery, they drive cardiovascular strain and next-day mortality. Health alerts must factor in minimum temperatures, not just daytime highs.
 

- Design heat-smart cities. Urban greening, shaded transit corridors, reflective surfaces, and ventilation corridors can significantly reduce street-level temperatures. Paris has begun experimenting with “oasis schoolyards,” while Barcelona’s “superblocks” add cooling greenery to dense neighborhoods — steps Thomson points to as scalable models.
 

- Bundle smoke with heat alerts. Fire seasons are now inseparable from heatwaves. Public-health advisories should combine temperature and air-quality risk, distributing masks, filtration guidance, and respiratory support when smoke intrudes.
 

- Protect outdoor workers. Heat stress is an occupational hazard. Flexible scheduling, mandatory breaks, and legal protections will reduce illness and productivity loss alike.
 

A Century-Scale Warning

If today’s fires and deaths are not enough, the long-term outlook reinforces the urgency. A Nature Medicine study projects 2.3 million additional temperature-related deaths in Europe by 2099 under a high-warming, low-adaptation scenario. Even with ambitious adaptation, the researchers concluded, many regions will see net increases unless greenhouse gas emissions are slashed.

For Thomson, the data from 2025 is a taste of what that future might hold if leaders fail to act. “What we’re seeing this summer are not anomalies,” she has emphasized in public forums. “They are signals of a new normal that health systems must prepare for.”

Why Health Framing Matters

Policy debates often frame heatwaves in terms of infrastructure, agriculture, or fire suppression. But Thomson insists that centering health changes the equation. When policymakers consider hospital surge capacity, ambulance availability, and the vulnerability of aging populations, adaptation becomes not just an environmental responsibility but a moral imperative.

And health framing, she argues, creates urgency. “It’s harder to ignore numbers like 2,300 deaths in ten days,” she has noted, pointing to this summer’s mortality estimate. “These are families and communities disrupted — preventable with the right systems in place.”

Conclusion

Europe’s summer of fire, smoke, and sleepless heat has exposed vulnerabilities that are structural, not seasonal. Mortality estimates, economic losses, and hectares burned all point to the same conclusion: without adaptation, climate change will erode both lives and livelihoods.

For Madeleine Thomson, the way forward is clear: treat extreme heat as a health emergency. Integrate climate and health data, redesign cities for resilience, protect workers, and ensure cooling access. These steps will not only reduce deaths this year but help avert the millions projected for later this century.

The choice, she argues, is between investing now or paying later in lives lost and economies destabilized. “The science is clear,” Thomson told Sky News. “The question is whether we act on it.”