Canadian forests becoming more prone to severe wildfires: Study

The treacherous combination of rising temperatures and dried-up fuels has made Canadian forest much more prone to severe wildfires in recent decades, a new study has found.

Driving these dangerous circumstances are the impacts of climate change, which is wreaking havoc in Canada's northern woodlands — among the most forested and fire-prone regions in the Northern Hemisphere, according to the study, published Thursday in Science.

"Canada is facing longer fire seasons with more-extreme and complex fire behavior driven by changing climate conditions," wrote the authors, led by Weiwei Wang, of the University of British Columbia and the Canadian Forest Service.

During a record-breaking 2023 fire season, blazes burned about 37 million acres, more than seven times the historic average for 1986 to 2022, the scientists noted.

To assess burn severity and its key drivers, the researchers combined 50 years of wildfire data to build a model that enabled them to analyze 10 Canadian ecological zones.

They found that fuel aridity — both the amount and the dryness of flammable vegetation — was the biggest driver of forest fire severity. They also observed that the summer months were more prone to severe burn conditions.

Northern Canada in particular, the researchers determined, experienced a dramatic surge in climate change-driven burn severity. In Southern Canada, meanwhile, fuel aridity and vegetation variations played a more instrumental role, per the study.

Evaluating their results, the researchers stressed the importance of considering burn severity maps in fire management and preparedness plans, including prescribed burn regimens. Certain severe fire-prone areas across Canada, they continued, also "overlap with greater population densities," indicating "an elevated threat to local communities, warranting greater attention and concern."

Jianbang Gan, a conservation expert at Texas A&M University who was not affiliated with the study, highlighted the urgency of the findings in an accompanying perspective piece, also published in Science.

“From an ecological perspective, the increase in fire activity in boreal forests, especially in the northern regions of the world, has raised grave concerns about the health and function of biomes that act as important carbon sinks,” Gan wrote. 

Boreal forests, also known as taiga, are the world's biggest biome and cover subarctic regions of the northern hemisphere. Canada's nearly 700-million-acre boreal forest, which is about 28 percent of the world's boreal zone, stores carbon, purifies air and water and acts as a climate regulator.

Emphasizing the critical nature of safeguarding the boreal from blazes, Gan emphasized a need for cooperation on this issue among the U.S., Canada and Russia — which collectively hold about 93 percent of this biome.

Such partnership, Gan added, is necessary "to effectively manage fire while preserving this valuable ecosystem of the northern hemisphere.”