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And the Costs are Much Greater Than Estimated

The intensity of recent wildfires in France and Spain defies comparison. The impact of just one fire complex in Spain was estimated to have released the energy of twenty-three atomic bombs. Attempting to characterize the experience, a Spanish firefighter texted a friend “everything we learned, everything we knew, everything that we have been learning for 25 years, means nothing.” French president Emmanuel Macron described the wildfire emergency as the country’s toughest challenge since the second world war. The increasing frequency and impact of wildfires is a fact: forest fires burn over twice as much tree cover each year as they did two decades ago and much more in some regions. Wildfires destroyed 2.2 million hectares across the European region in 2025, a rise of 57% in four years – a trend some have labeled “just the start”.

The impact of these enormous events in human terms is only recently being incorporated in climate risk assessments. News reports focus typically first on the value of property damage (estimated to be over $20 billion so far in Europe this year) and the need for evacuations (over 300,000 people). Mortality reports attributed to wildfires typically count only the short-term impacts of those unable to flee and overwhelmed by smoke, frequently in the hundreds or low thousands. This year the number in Europe has already topped 25,000.

In order to understand the health impacts of wildfire smoke it’s necessary to single out the largest and longest lasting source of damage to human health, fine particulate matter (PM2.5). This component of air pollution is a known contributor to diseases such as stroke, heart disease, lung cancer, chronic obstructive pulmonary diseases and respiratory infections, including pneumonia. These diseases can take years to fully develop and thus are not always properly linked to smoke events. A recent detailed peer-reviewed analysis concluded globally over 1.5 million deaths per year were attributable to wildfire smoke during 2000–19, an impact not considered in economic models.

Media coverage of wildfires frequently downplay or ignore the role of climate change. As UK geographer Doug Specht notes, “Europe’s fires were written up as a combination of holidays spoiled, energy policy rows, domestic civil protection issues and continental emergencies.” He credits recent reporting in France for giving more attention to the role of extreme weather and making reference to le dérèglement climatique (climate disruption). A few political leaders like Spain’s Prime Minister Pedro Sanchez and London mayor Sadiq Kahn have focused on the role of climate change and the urgent need to reduce emissions as an urgent priority. Meanwhile climate skeptics (led by President Trump) refuse to agree. In the US, Americans increasingly recognize the impact of extreme heat on their lives – but don’t always make the connection to climate change. Yet “attribution” studies leave little doubt about the role of climate change in making these events more frequent. As a detailed recent analysis of wildfires in France and Spain concluded,

In both regions, the likelihood and severity of [severe wildfire conditions] have been increased by human-caused warming; . . . extreme values are now at least twice as likely in southwestern France and at least 20 times as likely in central Spain.

Until recently it didn’t occur to anyone to model what might happen if major cities were regularly inundated with choking wildfire smoke because “it wasn’t thought possible.” With the increasing availability of data, the modeling has now been done by an international team of scientists and the conclusions are stunning: “When monetized, climate driven smoke deaths result in economic damages that exceed existing estimates of climate driven damages from all other causes in the USA”, notably without including the costs of property damage, firefighting, and evacuations. With high confidence, the scientists project wildfire smoke could cause almost 2 million excess deaths between 2026 and 2055 in the US alone.

Yet another impact outside previous projections was the prospect of food shortages due to the combined effect of heat waves and drought. In the UK, farmers are attempting to salvage such produce as they can while wheat farmers are looking at crops half the normal height. In Germany, agricultural yield estimates have been cut with crops harvested late, such as maize and sunflower, suffering a 6-7% loss.In parts of the US, fruit production is declining dramatically due to warmer evening temperatures – fewer “chill hours”. A World Bank report on the consequences of drought in South Africa paints a dire picture:

For the two-thirds of the region’s population who depend on rain-fed agriculture, these dry shocks don’t just threaten crops; they threaten survival. Rural employment drops by 7.4 percentage points when drought strikes, hitting women, older workers, landless farmers, and low-skilled laborers the hardest. The impact on landless rural farmers is nearly six times greater than average.

Not all significant impacts of extreme weather can be monetized, another challenge to communicating the urgent need for climate action. World Cultural Heritage sites, national parks, coral reefs, and the loss of thousands of plant and animal species are all among already evident trends due to climate change.

The fact these impacts are now happening and no longer remote possibilities enables better scientific understanding. In addition to wildfire smoke, scientists are also making much better forecasts of sea level rise and associated flooding, a field previously described as fairly “rudimentary.” A recent study breaks new ground by pinpointing climate changes increasingly dominant influence on both relative sea-level rise and extreme sea-level events — a link that previous analyses had only established for a single storm. The new more sophisticated analysis finds once-a-century floods now likely to strike roughly every 8 years, with potential costs in the many billions.

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In a previous blog post, I discussed how economic modeling by the Nobel laureate William Nordhaus seriously underestimated the risks of climate change due to the challenges predicting, much less quantifying, the dangers. As another Nobel Laureate, Paul Krugman wrote, “I’ve long been worried that these models understate the economic costs of climate change, because so many things you weren’t thinking of can go wrong.” Yet even recently climate skeptics continue to argue that the costs of climate change have been exaggerated.

So what to do? Some responses are possible in the short-term, including investment in better fire management (e.g., aerial firefighting equipment), risk warning systems, and adoption of evacuation plans. Over the longer term, changes in land use (e.g., brush clearing), incentives for more fire resilient buildings, and more effective evacuation routes. A topic for further discussion in future blog posts.

Alan Miller is a former climate change officer in the International Finance Corporation (2003–13) and climate change team leader, Global Environment Facility (1997–2003). Besides other engagements, Alan is an active editor for Climate Conscious submissions on Medium.