Forest fires: adapting and alleviating the impact of climate change

Each year, fire destroys 350,000 km² of forests and plants across the world, 4,500 km² of which are in southern Europe. These fires create significant challenges for the planet, including the safety of people, property, infrastructure, and ecosystem and biodiversity conservation. Understanding the effects of climate change is now a key target to limit the growth of fire risks and to anticipate the adaptations needed for future land management.

"Based on the increasing amounts of data available on climate and fires (Prométhée2 database in France), a clear link can be seen between climate evolution (hotter and drier weather conditions) and changes to fire behaviors. This link was only discovered relatively recently, but it has been reinforced by the convergence of scientific data across the world," comments Thomas Curt, Irstea researcher in Aix-en-Provence specializing in fire risks to forests and the ecology of fire.

Fires, a changing phenomenon

Under the combined influence of changes to climate, landscaping and soil use, fires are evolving. Fire season is now longer: for example, in France, fire risk was greatest during July and August, but now the season extends from early June to late September/early October. The number of fire-prone areas is expanding: fires are spreading north and to higher altitudes. Finally, the frequency of major fires is increasing, linked to extreme weather events (combining high temperatures, high winds and severe drought), as seen, for example, in the "mega-fire" that broke out in June 2017 in Portugal and devastated 45,000 hectares and left 65 dead.

People central to fire risks

In addition to highlighting these new trends, over the last 10 years, Irstea researchers have participated in research projects carried across Europe that have delivered essential lessons for the future of fire risk management. Of particular note are:

  • The central role played by humans, who cause more than 90% of fires (in Europe and the Mediterranean) and whose activities have affected climate, land use and landscapes;
  • The existence of a fire paradox: although burnt areas have decreased due to improvements in firefighting strategies since the 1990s, the number of large fires (bigger than 100 ha) has increased. In France, for example, while large fires make up only 2% of the total number of fires, they account for 70% of the total burnt area. These figures seem to show that there is a fire intensity threshold beyond which they cannot be contained by firefighting services.
  • An increase in risk due: first, to an increase in combustible areas (expansion of forests, brushwood areas, scrublands and maquis previously used as pasture) and second, to an intensification of exposure to human activity (new houses, infrastructure and networks that move ever closer to natural areas).

Solutions based on nature itself

These conclusions highlight the fact that a significant proportion of fire risks could clearly be reduced through changes in both collective and individual behavior. "In addition to reinforcing fire start prevention during critical periods and awareness of risks in urban planning strategies, sustainable solutions can also be implemented to protect people and help the landscape be more resistant and resilient to fire. It is essential that we develop a culture of fire risk assessment and distribute the action levers we have available to us," specifies Thomas Curt.

Irstea's scientists are aiming to use their research to provide specific and sustainable solutions to risk attribution at a regional scale. By focusing specifically on urban/forest interfaces, where urban areas come into contact with natural areas, they are looking to identify which ornamental species (hedges, trees) burn less easily, determine which ground-clearing process is the most efficient at stopping fires, and define the most resistant landscape organization processes (integrating firebreaks into combustible planted areas to avoid propagation). They are also looking at which species are most resilient and regenerate best after a fire.

Carried out over several years, this research regularly results in recommendations and practical guides for forest managers and public decision-makers to support them efficiently in managing the fire risks in their regions.

For more information

1- Program set up by the International Campus for Cooperation and Development, launched in 2016 by the University of Aix-Marseille, IRD and AFD.
2- Official database for forest fires in the French Mediterranean area. Created in 1973 with information provided by firefighting and fire prevention services, it currently contains over 100,000 fires.