Permafrost Thaw and Wildfires Continue to Decrease the Remaining Carbon Budget

Communications Earth & Environment, 24 January 2026

Increasing permafrost thaw, including “abrupt” thaw events, together with wildfire carbon emissions are reducing global human carbon budgets. Including new data on both abrupt thaw and wildfire emissions will lower the remaining carbon budget for 1.5°C by an additional 25%, and the 2.0°C budget by 17%, compared to models that ignore these processes. This study used an upgraded Earth system model to estimate the full impact of permafrost thaw and wildfires on these emissions. Rapid Arctic warming destabilizes carbon-rich permafrost, releasing gases that amplify climate change, but this process is not always gradual. Most global climate models still only simulate gradual, top-down permafrost thaw, omitting faster and more disruptive carbon release mechanisms such as abrupt thaw and fires. Even greater levels of ambition for national emissions reductions policies are therefore required for countries to fully align with the goals of the Paris Agreement.

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