Climate change doubled Canada fire weather odds, study says

Human-caused climate change made the extreme fire conditions behind this year's Canadian wildfires about twice as likely, according to a World Weather Attribution study released Thursday.

The researchers focused on the most extreme seven-day and 30-day periods of “fire weather” in Ontario and the Northwest Territories, two areas especially affected after prolonged hot and dry weather helped fires spread across Canada since July.

More than 3.8 million hectares, or 9.4 million acres, have burned in Canada so far this year. The fires have displaced thousands of people and exposed millions to dangerous smoke levels.

World Weather Attribution said the kind of fire weather seen this year is no longer rare in the current climate. The group said such conditions are now expected once every two to six years in the Northwest Territories and every six to 15 years in Ontario. Without climate change, it said, similar conditions would have occurred about once every 40 years.

Theodore Keeping of Imperial College London, the study's lead author, said Canadian wildfires since 2023 had been “fundamentally different in their scale and intensity.” He said the geographic spread showed adaptation alone was not enough and called for a rapid move away from fossil fuels.

The study said human-caused climate change is creating conditions for more frequent and intense wildfires by increasing heat, extending drought and drying organic matter.