Every smoky summer brings the same headline: climate change did this. The real picture is more complicated. Fire renews the boreal forest, people and lightning start the fires, a century of putting fires out has changed the forest around many towns, and a warmer climate is adding to the hot, dry, windy weather that lets fires spread. Only some of these are within our control.

Fire belongs in Canada’s forests

Fire has shaped Canadian forests since the last Ice Age. In a landmark study, Brian Stocks and colleagues wrote that in the boreal forest, fire is “critical to the very existence” of pine, spruce and aspen, and that these forests depend on periodic, high-intensity, stand-replacing fires. Natural Resources Canada calls fire “a vital ecological process that supports forest health and diversity.”

Organized fire control began in the early 1900s on the view that fire was destructive and should be eliminated, and Indigenous cultural burning was suppressed. Agencies became good at it: from 1959 to 1997, about 97 per cent of Canadian fires were put out before they reached 200 hectares.

That success has a cost. Parks Canada states that “fire suppression during the 20th century has caused a significant decline in ecosystem health and species diversity across the country.” A 2020 study of 160 boreal communities found that 54 per cent had less recently burned forest around them than their region would normally have. Young forest usually burns less readily than old forest, and the authors concluded that their findings “suggest that suppression policies are increasing flammability in the wildland–urban interface of boreal Canada.”

Who starts the fires, and how big the big years were

According to Natural Resources Canada, people started 49 per cent of Canada’s wildland fires between 1995 and 2024, and lightning started 47 per cent. But lightning fires accounted for 89 per cent of the area burned, compared with 6 per cent for human-caused fires. Lightning fires tend to start in remote, forested country, where they are harder to detect and reach, and can grow very large. Human-caused fires, from campfires, equipment, power lines and arson, start where people live and work.

Huge fire years are not new. The Canadian Large Fire Database records more than 7 million hectares burned in 1989, and again in 1995. The year 2023 was far larger: about 15 million hectares, roughly twice those earlier peaks, from about 6,700 fires. Some 232,000 people were evacuated. Lightning started 59 per cent of those fires but 93 per cent of the area burned, and 61 per cent of the area burned came from fires that were monitored or only partly fought rather than fully suppressed.

To be fair, a 2019 Canadian Forest Service study found that area burned and the number of large fires in Canada have increased significantly since 1959, that human-caused fires have declined, and that the fire season now starts about a week earlier and ends about a week later.

What the IPCC actually says

The Intergovernmental Panel on Climate Change is more careful than the headlines. Its Sixth Assessment Report says human influence has “likely increased the chance of compound extreme events since the 1950s,” including increases in “fire weather in some regions of all inhabited continents (medium confidence).” Fire weather means hot, dry and windy conditions. It is not the same thing as fires, which also need fuel and a spark.

On fires themselves, the report says: “Observed increases in areas burned by wildfires have been attributed to human-induced climate change in some regions (medium to high confidence).” It projects increases in fire weather in some regions at 2°C of warming and above (medium to high confidence). The same report lists “fire suppression in naturally fire-adapted ecosystems” as an example of maladaptation.

For 2023, a rapid World Weather Attribution study of Quebec found that climate change made that season’s hot, dry, windy conditions at least twice as likely and 20 to 50 per cent more intense. That study looked at weather only, not at ignitions or fuel. Federal researchers found that May to October 2023 was 2.2°C warmer than the 1991–2020 average across Canada.

The fair answer, then, is that a warmer climate is one factor raising the odds of dangerous fire weather. But it is one factor among several: people start about half of all fires, suppression has left older, more flammable forest near many boreal towns, and preparation decides how much damage a fire does.

What actually protects Canadians

  • FireSmart. This national program, founded in 1993, helps homeowners and neighbourhoods reduce risk within the 30-metre “Home Ignition Zone,” starting with a non-combustible area 1.5 metres around the house.
  • Prescribed and cultural burning. Parks Canada uses planned fire “to reduce wildfire risk and to restore and maintain ecological integrity.” Indigenous cultural burning once shaped local fire regimes, and Indigenous people hold deep, place-based knowledge of fire that can make prevention more effective.
  • Managing fuel near communities. Where decades of suppression have left old, dense forest around towns, thinning, fuel breaks and planned burns can reduce what a wildfire finds when it arrives.
  • Prevention. People still start about half of all fires. Careful campfires, equipment and debris burning remain the cheapest firefighting there is.

Canada will always have wildfires. The question is not whether the boreal forest burns, but whether our towns are ready when it does.

References

  1. Natural Resources Canada. Forest fires.
  2. Natural Resources Canada. Human-caused wildland fires in Canada: why prevention matters. The State of Canada’s Forests, 2026.
  3. Stocks, B. J., et al. (2002). Large forest fires in Canada, 1959–1997. Journal of Geophysical Research, 107, 8149.
  4. Parisien, M.-A., et al. (2020). Fire deficit increases wildfire risk for many communities in the Canadian boreal forest. Nature Communications, 11, 2121.
  5. Parks Canada. Prescribed fire.
  6. Jain, P., et al. (2024). Drivers and impacts of the record-breaking 2023 wildfire season in Canada. Nature Communications, 15, 6764.
  7. Hanes, C. C., et al. (2019). Fire-regime changes in Canada over the last half century. Canadian Journal of Forest Research, 49(3), 256–269.
  8. IPCC (2021). Summary for Policymakers, in Climate Change 2021: The Physical Science Basis. Statements A.3.5 and C.2.4.
  9. IPCC (2022). Summary for Policymakers, in Climate Change 2022: Impacts, Adaptation and Vulnerability. Statements B.1.1 and C.4.2.
  10. Imperial College London (2023). Scientists uncover the role of climate change in devastating East Canada fires (World Weather Attribution).
  11. FireSmart Canada. The Home Ignition Zone.