Estimates of Methane Release from the Arctic Seas under Possible Climate Changes during the 21st Century

To study the impact of future climate change on the methane emissions to the atmosphere as a result of the Arctic submarine permafrost degradation, scenario experiments were carried up to 2100 out using the SibCIOM ocean and sea ice model. For the atmospheric forcing, we used the results of six climate model simulations from the RCP8.5 scenario of the Coupled Model Inter-comparison Project Phase 5 archive. Based on the numerical results, it is found that the total annual methane fluxes will increase by a factor of 2–4 depending on the atmospheric forcing by 2100 compared to current levels. The flux intensity calculated in the numerical experiments does not exceed 8 Tg/yr. High future methane emissions are mainly due to reduced ice extent and increased ice-free periods. This resulted in a shift in the timing of maximal methane emissions from summer to fall and winter.