Abrupt Thaw and Wildfire Carbon Emissions Shrinking the Carbon Budget

Nature Communications Earth & Environment, 24 January 2026

Arctic warming is thawing carbon-rich permafrost, which contributes additional greenhouse gas emissions. Some of this thaw occurs gradually, but some occurs in “abrupt thaw” events, for example in association with wildfires, or when a hillside collapses and leads to exposure of permafrost soils. Many global models however only include gradual permafrost thaw in their emissions estimates, overlooking abrupt thaw processes as well as emissions from increasing wildfires in permafrost regions. Wildfires release carbon emissions during combustion, but also remove the insulating organic layer at the soil surface, increasing permafrost thaw and leading to additional post-fire emissions. When abrupt thaw, wildfires, and fire-driven thaw are included in models alongside gradual thaw, these combined processes reduce the remaining allowable carbon budget from 2025 onward by 25% when aiming for 1.5°C warming, and 17% at 2.0°C. This highlights the importance of including abrupt thaw and wildfire-related emissions when setting future human emissions reduction targets.

Paper | Summary by Woodwell Climate Research Center | Summary by Lead Author