Canadian wildfires could cost over $2 trillion in climate damage by 2100, study finds

A new study projects the climate damage from Canada's wildfires could exceed $2 trillion by 2100. The simulation, led by Simon Fraser University researchers, found that direct costs like firefighting and lost timber make up only two percent of the total. The remaining 98 percent comes from the global warming impact of carbon dioxide released by the fires. In a realistic worst-case scenario, the cumulative total reaches $2.14 trillion Canadian by the end of the century. The research was published in the journal Environmental Research: Climate.

"Societal and economic costs of wildfire are highly dependent on the actions that we take to mitigate climate change right now," said lead author Sian Kou-Giesbrecht, an assistant professor at Simon Fraser University. The team used a computer model to simulate Canada's forests, weather and fires from 1850 to 2100 under different warming scenarios. They compared these runs to a simulation with a climate frozen at pre-industrial conditions to isolate the effect of climate change. Under a future where global warming is limited to 2 degrees Celsius, climate change had no detectable impact on burned area, human exposure or costs by 2100. In hotter futures of 3 to 4 degrees or 4 to 5 degrees of warming, the effects were severe. By 2100, climate change roughly doubled the annual burned area in the 3 to 4 degree path and tripled it in the hottest scenario. This adds an extra 5.9 million hectares burned per year in the middle path and 7.9 million hectares in the hottest.

The record 2023 wildfire season burned 15 million hectares, seven times the average from 1986 to 2022. Kou-Giesbrecht noted a rise of 4 or 5 degrees is unlikely due to global green energy development. "A global temperature rise between 3 and 4 C is a more realistic worst-case scenario," she said. In that middle path, climate change added about $866 million annually in direct costs by 2100, mostly from lost timber, totaling $46 billion from 2015 to 2100.

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The far greater cost comes from the social cost of carbon, a metric Canada uses to price worldwide damage from CO2 emissions. Applying this cost to extra wildfire emissions, climate change added $42.2 billion per year from 2080 to 2100 in the middle path and $50.2 billion in the hottest. Over the entire century, these climate damages total $2.09 trillion and $2.43 trillion respectively. Combined with direct costs, the total reaches approximately $2.14 trillion by 2100.

The study also measured human exposure, counting someone as exposed if a fire burned at least one percent of a 50-kilometer map square. By 2100, climate change added 72,000 exposed people per year in the middle path and 178,000 in the hottest, more than triple the number without it. For someone born in the 2020s, the chance of experiencing wildfire exposure rises from 14 percent in a low-warming future to 25 percent in the middle path. About 78 percent of exposed populated areas were primarily Indigenous communities, which constitute 17 percent of populated areas overall.