30-40% of Arctic Permafrost Now a Net Source of Emissions

Nature Climate Change, 21 January 2025

Arctic tundra, forests, wetlands and permafrost store large quantities of carbon emissions, but new data indicates that at least 30% of this “boreal” zone is now releasing more carbon than it takes up during the growing season. Rising temperatures have transformed this frozen landscape into a net source of carbon emissions, either as CO2 or methane (CH4), which will increasingly contribute to global warming as more permafrost thaws. Researchers found that over 30% of the region has become a net source of carbon, or 40% if wildfire emissions are included. This work highlights the need to sustain long-term research focused on carbon dynamics in Arctic tundra regions, in order to accurately track which areas are net carbon sources. Natural carbon sequestration through global oceans, forest, and soils currently absorb roughly half of all human emissions, and this study raises a warning flag that these sinks are becoming strained at current levels of warming.

Full paper: https://www.nature.com/articles/s41558-024-02234-5
News coverage by The Guardian: https://www.theguardian.com/environment/2025/jan/21/third-of-arctic-carbon-sink-now-a-source-of-emissions-study