Arctic methane emissions
Release of methane from seas and soils in permafrost regions of the Arctic / From Wikipedia, the free encyclopedia
Arctic methane release is the release of methane from Arctic ocean floors, lake bottoms, wetlands and soils in permafrost regions of the Arctic. While it is a long-term natural process, methane release is exacerbated by global warming. This results in a positive climate change feedback (meaning one that amplifies warming), as methane is a powerful greenhouse gas.[1][2] The Arctic region is one of many natural sources of methane.[3] Climate change could accelerate methane release in the Arctic, due to the release of methane from existing stores, and from methanogenesis in rotting biomass.[4] When permafrost thaws as a consequence of warming, large amounts of organic material can become available for methanogenesis and may ultimately be released as methane.[5]
Large quantities of methane are stored in the Arctic in natural gas deposits and as methane clathrates under sediments on the ocean floors. Clathrates also degrade on warming and release methane directly.[6][7][8]
Atmospheric methane concentrations are 8–10% higher in the Arctic than in the Antarctic atmosphere. During cold glacier epochs, this gradient decreases to insignificant levels.[9] Land ecosystems are thought to be the main sources of this asymmetry, although it has been suggested in 2007 that "the role of the Arctic Ocean is significantly underestimated."[10] Soil temperature and moisture levels are important variables in soil methane fluxes in tundra environments.[11][12]
Mitigation of CO2 emissions by 2050 (ie reaching net zero emissions) is probably not enough to stop the future disappearance of summer Arctic Ocean ice cover. Mitigation of methane emissions is also necessary and this has to be carried out over an even shorter period of time.[13] Mitigation of methane emissions from human activities needs to be carried out within three sectors: oil and gas, waste and agriculture. Using available measures this would amount to global reductions of ca.180 Mt/yr or about 45% of the current (2021) emissions by 2030.[14]