Canada's wildfire paradox: fewer fires, greater destruction highlighted in new analysis

Canada's wildfire seasons are growing longer, larger and more destructive, according to a six-decade analysis of fire records by the federal government's Canadian Forest Service.

The study shows the trend isn't being driven by more frequent fires but by a smaller number of increasingly large wildfires that are burning more land than in the past, reinforcing a trend federal scientists first identified years ago.

In 2019, fire scientists with Natural Resources Canada published a study that suggested wildfire activity across the country had increased steadily since the mid-20th century, driven by rising temperatures and longer fire seasons.

The pattern was uneven at the time: Some regions showed clear increases in area burned, while others appeared stable or even declining. Human-caused fires were thought to be in retreat, reflecting decades of prevention efforts, and the largest fires, though growing, had not yet come to dominate the national picture.

The updated study, recently published in the Canadian Journal of Forest Research, extends that analysis through 2024 using improved satellite mapping and nine additional fire seasons that comprise several of the most severe on record, including 2021, 2023 and 2024.

The research found that the area burned from wildfires continues to rise across nearly all Canadian eco-zones, even in the Pacific Northwest and Atlantic Canada regions. Both were once considered lower risk because of wetter conditions but are now showing flat or increasing fire trends.

The study also illustrates how the largest fires now account for a growing share of the damage and that while lightning continues to drive most wildfires, human-caused fires have begun increasing again since the early 2000s — a shift the authors link not to policy failure but to hotter, drier conditions that make more ignitions harder to control.

"I think that increase in the human-caused fires, particularly the larger fires, is because the fuels are drier," said Chelene Hanes, a research scientist with the Canadian Forest Service at Natural Resources Canada's Great Lakes Forestry Centre in Sault Ste. Marie, Ont.

Hanes is the lead author of both the 2019 and 2025 national studies examining long-term changes in Canada's wildfire regime.

She said the largest fires now reach a scale and intensity where conventional firefighting tactics become limited, forcing crews to focus on containment and protection rather than stopping the fire outright.

Hanes said the impact of the largest wildfire events are becoming increasingly visible on a national scale.

"They're becoming responsible for a larger proportion of the burned areas because everything's so dry," she said.

The dynamics Hanes describes are no longer abstract datasets but have played out repeatedly in recent wildfire seasons across the country.

In July 2021, wildfires driven by extreme heat and record temperatures swept through British Columbia, notably destroying the village of Lytton, which had just recorded Canada's highest temperature on record, at 41.3 C.