Compared to 2001, forest fires now devastate approximately 3 million hectares more each year, an area equivalent to that of Belgium, according to satellite data compiled by the Global Forest Watch (GFW), the World Resources Institute (WRI) and the University of Maryland.
70% of the surfaces devoured by the flames in 20 years concern the boreal forests, which cover a large part of Russia, Canada and Alaska, and which constitute among the largest carbon sinks on the planet.
In Russia, 53 million hectares have burned since 2001, almost the size of France.
Fires, according to the study, account for more than a quarter of the total loss of forest cover since the turn of the century, with the rest caused by deforestation or other natural causes (storms and floods).
In the end, the loss of forest cover due to fires increases by about 4% per year, or 230,000 additional hectares. And about half of that increase is due to larger fires in boreal forests, “likely the result of warming temperatures in northern regions,” the researchers note.
They say climate change is “probably a major factor” in these increases, with extreme heat waves, which render forests arid, now being five times more likely today than a century and a half ago.
The destruction of the forest by these fires, aggravated by drought and high heat, leads to massive emissions of greenhouse gases, which further aggravates climate change through the mechanism of a “fire-climate feedback loop”. , they add.
“In these boreal regions, CO2 has accumulated in the ground for hundreds of years and has been protected by a moist layer on top,” GFW analyst James McCarthy told AFP. “These fires, more frequent and more severe, burn this upper layer and release this CO2”.
This dynamic, warns the study, could ultimately cause boreal forests to lose their status as carbon sinks.
The researchers call on governments to improve the resilience of forests by halting deforestation and limiting certain local forest management practices, including controlled burning, which is highly risky during periods of drought. “Forests are one of the best defenses we have against climate change,” McCarthy said.