Researchers found that a typical forest fire season now burns 3 million more hectares (7.4 million more acres) than in 2001.
Forest fires accounted for a quarter of global tree loss in the past 20 years.
A changing climate has caused boreal forests to ignite as never before. About 70% of all fire-driven tree loss over the past 20 years has occurred in boreal forests (climatic zone south of the Arctic, especially the cold temperate region dominated by swampy coniferous forest and forests of birch and poplar). These are warming at higher rates than other parts of the globe.
In 2021 alone, 6.67 million hectares of tree cover were lost in boreal forests, compared with just 1.16 million hectares lost in tropical forests such as the Amazon. In both cases, the loss of these trees and the thawing of permafrost threatens to release ancient stores of carbon, converting vast forests from climate-healthy carbon sinks into accidental polluters.
“We are seeing some severe fire years in the boreal and tropical forests in recent years,” said Alexandra Tyukavina, assistant research professor at UMD’s GLAD laboratory and the study’s lead author. “This is an alarming sign, and climate change likely plays a role.”
The threat from wildfires is expected only to grow globally, as the climate is all but guaranteed to continue to warm.
Scientists with the IPCC say that some of the worst-case warming scenarios would lead to 15 years of greenhouse gas emissions being released from the massive stores of carbon in these regions, something that could be curbed if the planet’s temperature increase is kept below the threshold of 2˚C (3.6˚F).