The Contribution from Methane to the Permafrost Carbon Feedback

Abstract

Purpose of Review: We assess the level of importance of methane (CH4) in the permafrost carbon feedback by reviewing recent scientific publications. Recent Findings: Studies that consider permafrost degradation in wetlands suggest that CH4 could have a share of ~20% in the warming caused by the total permafrost carbon release by 2100. When CH4 emissions from thermokarst lakes are considered, the contribution from permafrost CH4 to the surface warming increases to between 30 and 50%. Summary: Based on the reviewed literature, we report that gradual degradation of the near-surface permafrost under unmitigated emissions scenarios could result in an additional warming of ~0.3 (0.08–0.50) °C by 2100, out of which up to 0.1 °C would be from wetland CH4 emissions. However, these values can be underestimates as the degradation of ice-rich permafrost and subsequent CH4 emissions from thermokarst lakes are not accounted for in the calculations.