Direct and longer-term carbon emissions from arctic-boreal fires: A short review of recent advances

Increases in arctic-boreal fires can switch these biomes from a long-term carbon (C) sink to a source of atmospheric C through direct fire emissions and longer-term emissions from soil respiration. We here review advances made by the arctic-boreal fire science community over the last three years. Landscapes of intermediate drainage tend to experience the highest C combustion, dominated by soil C emissions, because of relatively thick and periodically dry organic soils. These landscapes may also induce a climate warming feedback through combustion and postfire respiration of legacy C, including from permafrost thaw and degradation. Legacy C is soil C that had escaped burning in the previous fire. Data shortages from fires in tundra ecosystems and Eurasian boreal forests limit our understanding of C emissions from arctic-boreal fires. Interactions between fire, topography, vegetation, soil, and permafrost need to be considered when estimating climate feedbacks of arctic-boreal fires. • C emissions from arctic-boreal fires originate from direct and longer-term emissions. • C emissions dominantly stem from soils and are dictated by topographic drainage. • Intermediate drainage positions are prone to releases of old legacy C. • More measurements are necessary from fires in tundra and Eurasian boreal forest. • Permafrost peatlands are vulnerable to C losses from intensifying fire regimes.