Three-Fourths of Carbon Emissions From 2023 Record-Breaking Wildfires in Canada Traced to Soil and Peat Combustion

Abstract

In 2023, wildfires burned vast areas in Canada, emitting large amounts of carbon (C). The area burned by the 2023 wildfires is the largest ever recorded in Canada, but the partitioning of C emissions between aboveground biomass and soil sources remains unknown. Here, we used ground, satellite, and fire weather observations to estimate C emissions from live aboveground biomass and soil sources. In total, 15.1 million hectares were burned, approximately seven times the 20-year average. The 2023 fires emitted 554 ± 51 teragrams of C (Tg C), of which 131 ± 24 Tg C were released from forest aboveground biomass and 423 ± 27 Tg C from soil organic C. This represents approximately 23% of the global C emissions from wildfires in 2023. Of the total burned area, 5.1 million hectares occurred in peatlands, releasing 180 ± 15 Tg C. Our study highlights the vulnerability of large soil C stocks found in Canada to increasing intensity of wildfires.