Don't Burn Up: Northern peat fire emissions and the remaining carbon budget

Despite estimates of climate target’s remaining carbon budget (RCB) informing critical policy, most climate projections do not account for peatland ecosystem processes, including the contribution of current or future peatland wildfires to global carbon emissions. Here, we provide the first estimate of the carbon emissions associated with non-permafrost northern peatlands that specifically includes both wildfire combustion and post-fire carbon dynamics. The inclusion of wildfire reduced the carbon sink from -59.5 ± 32.2 to -17.9 ± 45.7 g C m-2 yr-1 in natural (pristine) peatlands while degraded peatlands represented a consistent source of carbon (218.6 ± 48.1 g C m-2 yr-1). We find that small increases in average burn severity or peatland area burned (from 0.5 to 0.8 % yr-1) could tip northern peatlands from a net carbon sink to a net source, illustrating the critical importance of peatland wildfire emissions and their accounting to the RCB for global climate targets.