Organic matter storage and vulnerability in the permafrost domain

This chapter synthesizes information about the storage and vulnerability of organic matter in permafrost. The permafrost region is rapidly warming, leading to degradation and release of carbon. Permafrost holds a vast amount of organic carbon (∼1460–1600 gigatons (Gt = 109 t = 1012 kg) on land, and in total more than 4300 Gt (including organic carbon in subsea permafrost), making the permafrost domain the Earth's largest terrestrial carbon pool. The thawing of permafrost also affects ecosystem types and greenhouse gas emissions. Projections suggest that by 2100, the Arctic could release between 55 and 232 Gt carbon of CO2-equivalent, highlighting the potential to release carbon in amounts similar to that from a large industrial nation. While the possibility of a sudden release of greenhouse gases is not confirmed yet, permafrost destabilization increases the likelihood of the Arctic becoming a continuous carbon source, crucial to be included in climate mitigation considerations.