Canada’s 2023 wildfire season was the worst in the nation’s history. More than 15 million hectares (37 million acres), an area roughly the size of Ireland, burned between April and October, a new study found.
The ferocity of the fires was fueled by unusually hot and dry conditions across the boreal forest, which spans much of northern Canada. During the fire season, average temperatures were 2.2° Celsius (4° Fahrenheit) higher than average, the study found.
Canada heated up twice as fast as the rest of the world in 2023, a year that broke global temperature records.
Eight firefighters lost their lives battling the flames, while more than 230,000 people were forced to flee their homes in mass evacuations. Millions were exposed to hazardous air pollution from the unprecedented levels of thick smoke.
The area burned was seven times larger than average, and more than twice the previous record, set in 1989 when 6.7 million hectares (17 million acres) burned — making 2023 the worst wildfire season on record in Canada.
“I don’t think anyone ever thought that it was possible for so much [forest] to burn. This has shifted expectations of what’s possible,” said Piyush Jain, the study’s lead author, in a telephone interview. “It’s a precursor. Under continued warming, we’ll see similar conditions more frequently.”
The higher temperature, consistent with global warming trends, created the perfect tinderbox: vegetation, dried out by persistent heat, ignited easily, allowing fires to spread uncontrollably.
The intensity of the wildfires caused 140 pyrocumulonimbus events, Jain said, a phenomenon when firestorms get so big and hot that they create their own weather systems, including lightning and strong winds, causing fires to spread faster.
Climate change has tripled the risk of fires in Canada’s boreal forests, according to the 2023–24 State of Wildfires report, meaning the ecosystem is more prone to burning over larger areas and for longer periods.
The fires released more than 1.5 billion tons of CO2 — nearly equal to a decade’s worth of Canada’s usual wildfire emissions. This rapid release of CO2 worsens climate change by fuelling a feedback loop: More greenhouse gases cause warming, which increases the likelihood and intensity of future fires.
Lightning ignited 59% of the wildfires, but these accounted for an overwhelming 93% of the total area burned, as fires sparked in remote areas spread rapidly due to the extreme dry conditions and difficulty in deploying firefighters to these regions.
Looking ahead, scientists warn that fire seasons in Canada could become increasingly severe. “We should be prepared,” Jain said. “We haven’t seen anything like this in recent years, but severe fire seasons are becoming more common.”
Banner image: The 2023 wildfire season in Canada is now the worst on record. Satellites show the trail of destruction left in Quebec, Canada, on June 28. Image courtesy of the European Union, Copernicus Sentinel-2.
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