Everywhere, the planet is literally burning. In France, fires are ravaging the pine forests of Gironde as well as the Monts d’Arrée, in Finistère. In recent weeks, they have affected the Var, the Gard, the Cévennes, the Pyrénées-Orientales and even in Normandy. Elsewhere, the flames have destroyed hundreds of thousands of hectares in Spain, Portugal, Greece, Turkey or the United States, where the giant sequoias of Yosemite National Park have however been spared. Dramatic phenomena called to multiply. Climate change will indeed lead to more megafires on the planet in the coming decades.
Rising global temperatures (+1.1°C since pre-industrial times), increased frequency of heat waves and droughts form a fatal mix that has already increased conditions conducive to fires in many regions of the world. This is particularly the case in southern Europe, northern Eurasia, the United States, Australia, Amazonia, but also in Siberia or Canada. On a global scale, the seasons where these conditions are met have seen their duration increase by 20% between 1979 and 2013 and the potentially burnable surface has doubled.
“Global warming amplifies the risk of fire, because it extends the risk zones, which go up in altitude and latitude, the fire season starts earlier and ends later, and the rise in night temperatures reduces the window of fire. ‘intervention of firefighters who took advantage of the night to stop the fires’, specifies Renaud Barbero, climatologist at the National Research Institute for Agriculture, Food and the Environment (Inrae) in Aix-en-Provence.
More effective prevention since the 2003 heat wave
However, these dangerous situations do not always lead to fires. The area actually burned has actually been decreasing in recent decades worldwide – it fell by 25% between 1998 and 2015. But the main explanation lies in the conversion of forests to agricultural land in the tropics, “massive deforestation which reduces the amount of fuel and therefore fires”explains Renaud Barbero.
In France and Europe, on the other hand, the ” outstanding ” reduction in surface areas that went up in smoke is linked to the” efficiency “ policies for preventing and fighting fires, assures Jean-Luc Dupuy, research director at Inrae in Avignon. Put in place after the destruction record recorded in 2003 (73,000 hectares), at the time of the historic heat wave, they consist of attacking any outbreak of fire “systematically and very quickly”. As a result, the areas burned in the south of France were divided by four between the decades of 1980 and 2010, going from 30,000 to 6,700 hectares consumed annually, while the number of fires was divided by two. Conversely, the areas burned have jumped in the United States (+1,200% over the last three or four decades), Australia and Canada.
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