The Arctic region contains extensive amounts of carbon, accumulated over millennia in terrestrial and sub-sea permafrost, that can be re-introduced back into the present day atmosphere and biosphere biogeochemical cycle, and thus feedback processes affecting global climate dynamics may be accelerated. One of the feedback processes is related to destabilization of significant quantities of the gas hydrate deposits and to consequent production of methane that can seep to the water column through pathways in sub-sea permafrost. The state of permafrost in Arctic is a potential key to understanding whether and how methane, preserved in seabed reservoirs, can escape to the atmosphere. Unlike the terrestrial permafrost in the Arctic which experienced a change in its thermal regime caused by the 6-7C mean annual air temperature increase since the last Glacial Maximum, sub-sea permafrost has been subjected to additional drastic transformations, e.g. inundation by the ocean, resulting in warming of the permafrost environment by as much as 17-20C.
展开▼
