HR: 1340h
AN: A13B-0099    [Abstracts]
TI: Modeling the Impact of Changing Climate and Permafrost on Emission of Greenhouse Gases From the Arctic Wetlands.
AU: * Anisimov, O
EM: oleg@oa7661.spb.edu
AF: State Hydrological Institute, Second Line V.O., 23, St.Petersburg, 199053 Russian Federation
AU: Reneva, S
EM: svetkina@pisem.net
AF: State Hydrological Institute, Second Line V.O., 23, St.Petersburg, 199053 Russian Federation
AB: There is growing evidence that climatic warming and changes in permafrost may enhance the emission of the greenhouse gases from the Arctic wetlands. Arctic soils contain approximately 455 Gt C, or 14% of the global soil carbon of which about 50Gt C are accumulated in the Arctic wetlands. Deeper seasonal thawing may lead to enhanced decomposition of the organic material and release of soil carbon to the atmosphere in the form of either CO2 (typical for dry soils with high ventilation), or CH4 (typical for wetlands where decomposition takes place under anaerobic conditions). We used the digital contours of 112,520 Siberian wetlands, permafrost and soil carbon models, and GCM-based scenarios of future climate to calculate the changes in the volume of seasonally thawing organic-rich soil and emission of greenhouse gases from the wetlands in the Russian Arctic. By 2050 the overall volume of seasonally thawing carbon-rich soils is likely to increase on average by 20% - 30%. The largest relative increase, up to 50%, will be in the northernmost permafrost locations while in the southern zone of sporadic permafrost increase in the volume of seasonally thawing organic material will be relatively small, within 10%-15%. Such changes of permafrost, higher soil temperature and longer warm period may lead to enhanced emission of greenhouse gases. It may increase by 80% at selected locations along the arctic coast, by 30%-50% over the discontinuous permafrost region, and up to 20% in the southern permafrost zone. Better drainage conditions and enhanced evapotranspiration under warmer climate may lower the water table and improve soil ventilation, ultimately shifting the currently existing balance in favor of CO2 rather than CH4 production.
DE: 1615 Biogeochemical processes (4805)
DE: 0315 Biosphere/atmosphere interactions
DE: 0330 Geochemical cycles
DE: 0400 Biogeosciences
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting