[Case Study] Anticipating wildfire risk across industrial sites in France
The wildfires that affected Gironde and the Landes in 2022, and again in 2026, demonstrated that wildfires can pose a real threat to industrial facilities. More recently, the Fontainebleau forest fire near Paris highlighted another dimension of the changing wildfire risk landscape: exposure is no longer confined to the regions historically affected by major fires. As climate change increases the frequency and intensity of extreme fire weather conditions, wildfire risk is expected to expand further across France. But what is the level of wildfire risk facing industrial facilities today, and how will it evolve in the coming decades?
This case study shows how Fire Weather Index (FWI) projections combined with high resolution land use and forest data can be used to assess changing wildfire exposure across industrial sites. We focus on Seveso sites in metropolitan France, providing a concrete example of how climate projections can be translated into actionable information for industrial risk management at scale.
Fire Weather: A Growing Threat for Industry and Infrastructures
Recent major wildfires, including the Los Angeles wildfires in 2025 and the Gironde fires in France in 2026, have raised awareness of wildfire risk among homeowners, urban planners and insurers. But residential and commercial buildings are not the only assets exposed to wildfires. Industrial facilities, utilities and critical infrastructure can also face significant wildfire risks, with potentially catastrophic consequences.
The Uljin fire in March 2022 offered a striking example: it was stopped just meters from one of the world's largest nuclear plants.
These events highlight the particular challenges posed by wildfires near hazardous industrial sites and critical infrastructure. A wildfire can cause substantial economic losses, prolonged operational disruptions and environmental damage. It can also complicate emergency response, as firefighting resources may need to be deployed to protect critical facilities and prevent fires from spreading to hazardous installations.
This string of recent events raises a critical question: are these isolated events, or do they reflect a broader and growing exposure of industrial sites to wildfire risk? And how could this risk evolve as climate change alters fire weather conditions?
Callendar Expertise: Combining Climate Projections and Physical Environment Data to Identify Facilities at Risk
In 2022, Callendar published a first assessment of wildfire exposure across Seveso classified industrial sites in France. The study provided one of the first nationwide assessments of how climate change could affect wildfire exposure across hazardous industrial facilities and influenced the 2023 French law on wildfire prevention. Four years later, we have updated the analysis to account for changes in industrial locations, improved forest data and new climate projections aligned with France’s official reference climate trajectory, the Trajectoire de Référence pour l’Adaptation au Changement Climatique (TRACC).
In this case study, we assess wildfire exposure across more than 1,300 hazardous industrial facilities covered by the European Seveso Directive in metropolitan France. These facilities range from petrochemical refineries to space and defense industry or water treatment plant. They handle large quantities of hazardous substances and are subject to specific requirements for preventing and managing major industrial accidents.
Our objective is to identify facilities that could be exposed to wildfire and quantify how this exposure could evolve under climate change.
As discussed in a previous post, the Fire Weather Index (FWI) is a widely used indicator of wildfire danger. It combines meteorological variables such as temperature, relative humidity, precipitation and wind to characterise the conditions that influence wildfire ignition and spread. FWI can therefore be used both for short term fire weather forecasting and to assess how wildfire danger could evolve over the coming decades as the climate changes.
However, weather conditions alone do not determine wildfire exposure at a specific location. The surrounding physical environment is equally important. Even under highly favourable fire weather conditions, wildfire exposure may remain limited if there is little combustible vegetation in the surrounding area.
We therefore combined climate projections with land cover data to identify industrial facilities located in environments where wildfires could potentially reach the site.
Our team developed an automated methodology using detailed land cover and forest data derived from satellite observations. For each facility, we calculated the proportion of forest and shrubland within 1 km and 5 km of the site. This allowed us to identify installations located close to substantial areas of potentially combustible vegetation and to assess how their exposure to fire weather conditions could evolve over time.
Using Fire Weather Index Projections to Assess Current and Future Wildfire Exposure
This first analysis identified approximately one third of France’s hazardous industrial facilities as being located close enough to wooded areas to potentially be exposed to wildfires. The next step was to determine whether the weather conditions around these facilities are becoming conducive to more frequent and severe wildfire danger.
To assess this, we calculated daily Fire Weather Index (FWI) values from 1976 to 2100 using high resolution climate projections for temperature, humidity, wind and precipitation. This provides a consistent way to quantify how fire weather conditions could evolve at the location of individual industrial facilities. While this analysis focuses on France, the same approach can be applied to industrial sites and critical infrastructure in other regions.
We focused on the annual number of days with high fire weather danger, defined here as days with an FWI above 40. This threshold provides a criterion for identifying periods when weather conditions are particularly favourable to wildfire development and spread.
Because Callendar produces and processes its own climate projections, we can adapt them to our needs. For this study, we wanted to use a framework consistent with France’s new Trajectoire de Référence pour l’Adaptation au Changement Climatique (TRACC), which provides a common reference for climate adaptation planning in France. As a result we assessed wildfire exposure at three global warming levels: +1.5°C, representative of conditions around 2030, +2°C, representative of mid century conditions around 2050, and +3°C, representative of late century conditions around 2100. We compared these projections with a historical reference climate corresponding to the 1976 to 2005 period. This
To account for uncertainty across climate models, we performed the analysis using an ensemble of 10 independent climate models. In line with scientific practices, we used the multi model median to characterise as the most likely outcome.
The Changing Landscape of Wildfire Risk For Hazardous Industrial Sites in France
The analysis shows that climate change has already significantly altered the wildfire danger faced by hazardous industrial sites in France.
In the climate of the 1990s, most of the 467 sites located near forests were rarely exposed to high fire weather danger. Today, three quarters of these sites experience at least one day of high fire weather danger per year on average, while one site in six experiences more than five such days per year.
The geographical distribution of wildfire danger is also changing. High fire weather conditions are increasingly affecting areas further north and west, including the Paris region. In Île de France, the 35 Seveso sites located near forests currently experience an average of 3.2 days of high fire weather danger per year, compared with just 0.3 days in the historical reference climate.
This geographical shift is particularly relevant for industrial risk management. A facility does not need to be located in a region historically associated with wildfires to become exposed to wildfire risk during its operational lifetime.
The proportion of industrial facilities exposed to more than five high risk days per year increases from 8% in the 1990s reference climate to 16% today, 46% around mid century and 62% by the end of the century.
The projections indicate that this increase in wildfire exposure will continue throughout the century. By mid century, almost all of the sites analysed are expected to experience high fire weather danger regularly.
The increase is particularly pronounced in western France and around the Paris region. By the end of the century, the sites analysed could experience an average of 17 high fire weather danger days per year in Charente, 14 in Loire Atlantique and 9 in Île de France. In regions that are already highly exposed, periods of elevated wildfire danger could last for several weeks each year.
Average Conditions Can Hide Much More Severe Years
Another important finding is the large internannual variability in projected fire weather conditions. In simple terms, average climate conditions can hide years in which wildfire exposure is much higher.
An unusually hot or dry year can produce levels of fire weather danger substantially above the long term average. In our projections, conditions expected around mid century can already occur today in roughly one year out of five. This means that looking only at average conditions can give a misleading impression of the time available to adapt. Conditions that are expected to become the norm several decades from now can already occur occasionally today.
For industrial facilities, this is an important distinction. Climate adaptation is not only about preparing for the average conditions expected several decades from now. It also requires understanding the likelihood of exceptionally adverse years that may occur well before those average conditions become the norm.
At Callendar, we combine climate science, detailled data and industrial risk expertise to assess how climate hazards can affect individual assets and sites. Our approach is designed to move from projections to operational risk assessment: identifying where exposure is changing, quantifying how conditions could evolve over the lifetime of an asset, and translating these results into information that can be used by engineers, risk managers and decision makers.
As wildfire risk expands geographically and intensifies with climate change, understanding future fire weather conditions is becoming an increasingly important component of industrial risk management.
Are your industrial sites prepared for the climate conditions of today and tomorrow? Contact Callendar to assess the climate exposure of your sites.
