Canadian wildfire impacts and global societal costs attributed to climate change over the 21st century

Wildfires in Canada are intensifying due to anthropogenic climate change, with far-reaching impacts on ecosystems, human well-being, and the global climate system. However, the long-term societal costs of future wildfires and the extent to which they will be shaped by climate change remain poorly quantified. Here, we project Canadian wildfire impacts over the 21st century and attribute projected changes in burned area, exposure, costs, and CO2 emissions to anthropogenic climate change under three Shared Socioeconomic Pathways (SSP1-2.6, SSP3-7.0, and SSP5-8.5). We use a process-based wildfire model that explicitly represents fire weather, vegetation growth dynamics, lightning and human ignitions, and suppression, enabling attribution to climate change through simulations with a pre-industrial climate. We quantify impacts in terms of exposed population, direct local and national costs (suppression, net timber yield loss, and nature-based recreation value loss), and the globally distributed societal cost of wildfire CO2 emissions using the social cost of carbon. We find that limiting global warming to below 2.0 °C as set out by the Paris Agreement keeps the annual burned area, CO2 emissions, exposure, and societal costs of wildfires comparable to modern levels. In contrast, under high-emissions scenarios, anthropogenic climate change substantially amplifies wildfire activity by the end of the century, increasing population exposure by up to over 300%, direct costs by up to approximately 870 million $ yr−1, and the global societal cost of wildfire CO2 emissions by up to approximately 50 billion $ yr−1 (2025 CAD). Overall, our results demonstrate that climate change is the dominant driver of future wildfire impacts and associated costs, and that incorporating climate-change-driven CO2 emissions from wildfire into the social cost of carbon is essential for fully capturing the future societal burden of climate change.