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GEOPHYSICAL RESEARCH LETTERS, VOL. 31, L04501, doi:10.1029/2003GL018680, 2004

Thawing sub-arctic permafrost: Effects on vegetation and methane emissions

Torben R. Christensen

Department of Physical Geography and Ecosystems Analysis, GeoBiosphere Science Centre, Lund University, Sweden


Torbjörn Johansson

Department of Physical Geography and Ecosystems Analysis, GeoBiosphere Science Centre, Lund University, Sweden


H. Jonas Åkerman

Department of Physical Geography and Ecosystems Analysis, GeoBiosphere Science Centre, Lund University, Sweden


Mihail Mastepanov

Department of Physical Geography and Ecosystems Analysis, GeoBiosphere Science Centre, Lund University, Sweden


Nils Malmer

Department of Ecology, Plant Ecology and Systematics, Lund University, Sweden


Thomas Friborg

Institute of Geography, Copenhagen University, Denmark


Patrick Crill

Complex Systems Research Center, University of New Hampshire, USA


Bo H. Svensson

Department of Water and Environmental Studies, Linköping University, Sweden


Abstract

Ecosystems along the 0°C mean annual isotherm are arguably among the most sensitive to changing climate and mires in these regions emit significant amounts of the important greenhouse gas methane (CH4) to the atmosphere. These CH4 emissions are intimately related to temperature and hydrology, and alterations in permafrost coverage, which affect both of those, could have dramatic impacts on the emissions. Using a variety of data and information sources from the same region in subarctic Sweden we show that mire ecosystems are subject to dramatic recent changes in the distribution of permafrost and vegetation. These changes are most likely caused by a warming, which has been observed during recent decades. A detailed study of one mire show that the permafrost and vegetation changes have been associated with increases in landscape scale CH4 emissions in the range of 22–66% over the period 1970 to 2000.

Received 21 September 2003; accepted 8 January 2004; published 20 February 2004.

Index Terms: 0315 Atmospheric Composition and Structure: Biosphere/atmosphere interactions; 1610 Global Change: Atmosphere (0315, 0325); 1615 Global Change: Biogeochemical processes (4805); 1832 Hydrology: Groundwater transport; 1890 Hydrology: Wetlands.

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Citation: Christensen, T. R., T. Johansson, H. J. Åkerman, M. Mastepanov, N. Malmer, T. Friborg, P. Crill, and B. H. Svensson (2004), Thawing sub-arctic permafrost: Effects on vegetation and methane emissions, Geophys. Res. Lett., 31, L04501, doi:10.1029/2003GL018680.