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GEOPHYSICAL RESEARCH LETTERS, VOL. 33, L02503, doi:10.1029/2005GL024960, 2006

Abrupt increase in permafrost degradation in Arctic Alaska

M. Torre Jorgenson

ABR, Inc., Fairbanks, Alaska, USA


Yuri L. Shur

Department of Civil and Environmental Engineering, University of Alaska, Fairbanks, Fairbanks, Alaska, USA


Erik R. Pullman

ABR, Inc., Fairbanks, Alaska, USA


Abstract

Even though the arctic zone of continuous permafrost has relatively cold mean annual air temperatures, we found an abrupt, large increase in the extent of permafrost degradation in northern Alaska since 1982, associated with record warm temperatures during 1989–1998. Our field studies revealed that the recent degradation has mainly occurred to massive wedges of ice that previously had been stable for 1000s of years. Analysis of airphotos from 1945, 1982, and 2001 revealed large increases in the area (0.5%, 0.6%, and 4.4% of area, respectively) and density (88, 128, and 1336 pits/km2) of degrading ice wedges in two study areas on the arctic coastal plain. Spectral analysis across a broader landscape found that newly degraded, water-filled pits covered 3.8% of the land area. These results indicate that thermokarst potentially can affect 10–30% of arctic lowland landscapes and severely alter tundra ecosystems even under scenarios of modest climate warming.

Received 14 October 2005; accepted 5 December 2005; published 24 January 2006.

Index Terms: 0439 Biogeosciences: Ecosystems, structure and dynamics (4815); 0475 Biogeosciences: Permafrost, cryosphere, and high-latitude processes (0702, 0716); 0476 Biogeosciences: Plant ecology (1851); 0480 Biogeosciences: Remote sensing; 0486 Biogeosciences: Soils/pedology (1865).

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Citation: Jorgenson, M. T., Y. L. Shur, and E. R. Pullman (2006), Abrupt increase in permafrost degradation in Arctic Alaska, Geophys. Res. Lett., 33, L02503, doi:10.1029/2005GL024960.