A new study from McMaster University, published in Geophysical Research Letters, reveals that Canada's record 2023 wildfire season released 554 million tonnes of carbon, with 76% coming from burning soil and peat rather than trees. The fires burned 15.1 million hectares, seven times the 20-year average, and accounted for nearly a quarter of global wildfire emissions that year. The research highlights how hotter, drier conditions are turning Canada's peatlands from fire buffers into major carbon sources. Peatlands, which store 20% of the world's soil organic carbon, are normally waterlogged and fire-resistant. But drought has lowered water tables, allowing fires to burn deep into these ancient carbon stores. For carbon market participants, this underscores the risk that natural carbon sinks can become sudden emission sources under climate stress. It also raises questions about how wildfire emissions are accounted for in national inventories and offset projects that rely on forest and peatland conservation.
