The 2023 Canadian wildfires were exceptionally severe, with emissions exceeding those of the previous four decades. Using satellite data, researchers estimated carbon emissions from May to September 2023 at 647 TgC (570–727 TgC), comparable to India's annual fossil fuel emissions. The fires were driven by extreme hot and dry weather, with 2023 being the warmest and driest year since at least 1980. Climate projections suggest such conditions may become typical by the 2050s under moderate mitigation scenarios, likely increasing fire activity and reducing the carbon uptake capacity of Canadian forests. Canadian forests, covering 362 million hectares, are a significant carbon sink, but climate change is increasing fire frequency, threatening their role as a carbon sink. The study also highlights the importance of monitoring carbon budget changes across both managed and unmanaged lands. Canadian ecosystems are currently a carbon sink, absorbing 366 TgC of CO2 annually. However, the 2023 fires could undermine this role, as fires have been shown to suppress carbon uptake in Canadian forests over the past 30 years. The study underscores the need for improved fire management strategies and climate adaptation measures to mitigate the impacts of increasing fire activity on Canada's carbon budget.The 2023 Canadian wildfires were exceptionally severe, with emissions exceeding those of the previous four decades. Using satellite data, researchers estimated carbon emissions from May to September 2023 at 647 TgC (570–727 TgC), comparable to India's annual fossil fuel emissions. The fires were driven by extreme hot and dry weather, with 2023 being the warmest and driest year since at least 1980. Climate projections suggest such conditions may become typical by the 2050s under moderate mitigation scenarios, likely increasing fire activity and reducing the carbon uptake capacity of Canadian forests. Canadian forests, covering 362 million hectares, are a significant carbon sink, but climate change is increasing fire frequency, threatening their role as a carbon sink. The study also highlights the importance of monitoring carbon budget changes across both managed and unmanaged lands. Canadian ecosystems are currently a carbon sink, absorbing 366 TgC of CO2 annually. However, the 2023 fires could undermine this role, as fires have been shown to suppress carbon uptake in Canadian forests over the past 30 years. The study underscores the need for improved fire management strategies and climate adaptation measures to mitigate the impacts of increasing fire activity on Canada's carbon budget.