With rising temperatures, thawing Arctic permafrost could be emitting greenhouse gases from previously unaccounted-for carbon stocks. Particularly affected is so-called ‘yedoma’ permafrost widespread in areas not covered by ice sheets during the last ice age. It contains up to 80% ice, especially susceptible to abrupt thaw (thermokarst), causing the bedrock to collapse and erode. Such processes make previously stored carbon accessible to microorganisms, which break it down and release CO2 and methane. 130 gigatons of organic carbon were found in Yedoma, parts well-preserved and available for fast decomposition. Moreover, part of the nitrogen liberated may be released as the strong greenhouse gas (GHG) nitrous oxide (N2O). Just how serious all this will prove to be remains unknown.
www.sciencedaily.com/releases/2022/01/220128100750.htm
www.sciencedirect.com/science/article/pii/S0012825217300508
pubs.rsc.org/en/content/articlehtml/2020/em/d0em00097c
www.nature.com/articles/s41467-021-27386-2