Tinande permafrost: University of Colorado Boulder

Permafrost, a perpetually frozen layer under the seasonally thawed surface layer of the ground, affects 18 million square kilometers at high latitudes or one quarter of all the exposed land in the Northern Hemisphere. Current estimates predict permafrost contains an estimated 1,500 petagrams of carbon, which is equivalent to 1.5 trillion metric tons of carbon.

Kolet är i form av metan bundet i is samt biologiskt kol (djur- och växtrester) som anaeroba [1] bakterier producerar metangas av när temperaturen så tillåter.

https://www.colorado.edu/today/2020/02/03/arctic-permafrost-thaw-plays-greater-role-climate-change-previously-estimated

Permafrost contains rocks, soil, sand, and in some cases, pockets of pure ground ice. It stores on average twice as much carbon as is in the atmosphere because it stores the remains of life that once flourished in the Arctic, including dead plants, animal and microbes. This matter, which never fully decomposed, has been locked away in Earth’s refrigerator for thousands of years. 
Metan oxideras till koldioxid och vatten i atmosfären, endera snabbt genom förbränning eller långsamt genom att de enskilda molekylerna så sakta ‘nöts ner’ av atmosfärens syre.

Nyutsläppt metangas har strax över 80 gånger så hög växthuseffekt som koldioxid. Över en mänsklig livstid minskar potentialen till 10-20 gånger men aldrig under koldioxidens som är slutstationen.

A massive thaw slump on the Yedoma coast of the Bykovsky Peninsula is inspected by an Alfred Wegener Institute permafrost team. (Credit: Guido Grosse, Alfred Wegener Institute

“The impacts from abrupt thaw are not represented in any existing global model and our findings indicate that this could amplify the permafrost climate-carbon feedback by up to a factor of two, thereby exacerbating the problem of permissible emissions to stay below specific climate change targets,” said David Lawrence, of the National Center for Atmospheric Research (NCAR) and a coauthor of the study.

[1] Aeroba bakterier använder syre vid sin metabolism, anaeroba gör det inte. Av det skälet producerar aeroba bakterier CO2 medan anaeroba gör CH4 (metan)