HR: 1340h
AN: GC23A-0988    [Abstracts]
TI: Feedback of the changing Russian permafrost to the global climate system through methane emission.
AU: * Anisimov, O
EM: oleg@oa7661.spb.edu
AF: State Hydrological Institute, 23 2nd Line V.O., St Petersbutg, 199053, Russian Federation
AU: Reneva, S
EM: svren@mail.ru
AF: State Hydrological Institute, 23 2nd Line V.O., St Petersbutg, 199053, Russian Federation
AB: Large amounts of soil carbon deposited in permafrost may be released due to deeper seasonal thawing under the projected for the future climatic conditions. Increase in the volume of the available organic material together with the higher ground temperatures may lead to enhanced emission of greenhouse gasses. Particular concerns are associated with methane, which has much stronger greenhouse effect than the equal amount of CO2. Production of methane is favored in the wetlands, which occupy up to 0.7 mln km2 in Russian permafrost regions and have accumulated about 50 Gt C. We used the permafrost model and several climatic scenarios to construct the projections of the soil temperature and depth of seasonal thawing. Results for the mid-21st century climate indicated up to 50 % increase in the depth of seasonal thawing in the northernmost locations along the Arctic coast and in the East Siberia, where wetlands are sparse, and relatively small increase by 10-15 % in the West Siberia where wetlands occupy 50-80 % of land. These results together with the projected for the future soil temperatures have been used in the carbon model to estimate the changes in the methane fluxes. According to our results, by mid-21st century the annual net flux of methane from Russian permafrost regions may increase by 6-8 Mt, depending on climatic scenario. If other sinks and sources of methane remain unchanged, this may increase the overall content of methane in the atmosphere by approximately 100 Mt, or 0.04 ppm and lead to approximately 0.01 C global temperature rise.
DE: 0702 Permafrost (0475)
DE: 0793 Biogeochemistry (0412, 0414, 1615, 4805, 4912)
DE: 0798 Modeling
DE: 1621 Cryospheric change (0776)
SC: Global Environmental Change [GC]
MN: 2007 Fall Meeting