Permafrost Thawing in Alaska and Global Implications

Air temperatures in Alaska across a number of different monitoring sites have increased since the late 1970s. As ice rich permafrost melts, a thermokarst landscape is produced, leaving marshy land interspersed with  shallow lakes due to the settlement of ground following permafrost thaw. In a recent study, Osterkamp (2007) tried to establish a link between mean annual air  temperature and permafrost thickness temperature.

   Osterkamp (2007) found that permafrost temperatures have increased by between 0.3 and >6oC in some areas of northern Alaska because of rising air temperatures and an increase in snow cover. He found complex relationships between surface cover (vegetation and snow), air temperature, local hydrology and geothermal activity with permafrost temperatures. It was observed during the research that thermokarst now exists in areas where it was absent in the 1980s in both northern and interior Alaska.

    At a regional scale, the thawing of permafrost causes problems for ecosystems and infrastructure which require the stability of permafrost. Thawing ground can be a major problem for roads, buildings and can significantly change local hydrology. This is an important issue for Alaskans in particular, with around 80% of Alaska underlain by permafrost (Osterkamp et al., 1998). On a global scale, it seems the thawing of permafrost should be factored into models of climate change and atmospheric carbon. There is thought to be more carbon stored within permafrost than is in circulation in the modern atmosphere (Bowden, 2010), and would form a significant positive feedback loop should this carbon be released into the atmosphere.

    Models produced by Schaefer et al. (2011) suggest a reduction in permafrost area of 29-59% by 2200. This thawing would result in an irreversible contribution of between 126 and 254 Gt of carbon into the atmosphere. It would seem that it's not only those at high latitudes that should be concerned by the thawing of permafrost.

    See also:    http://www.biology.ufl.edu/permafrostcarbon/index.html


    References


Bowden, W. B., 2010. Climate change in the Arctic- permafrost, thermokarst and why they matter to the non-Arctic world. Geography Compass. Vol 4 (10), p1553-1566.


Osterkamp, T. E., Esch, D. C., and Romanovsky, V. E.: 1998, ‘Chapter 10: Permafrost. implications of global change in Alaska and the Bering Sea region’, in Weller, G. and Anderson, P. (eds.), Proceedings of a Workshop at the University of Alaska Fairbanks, 3–6 June 1997, Published by the Center for Global Change and Arctic System Research, University of Alaska Fairbanks, p115–127.


Osterkamp, T. E., 2007. Characteristics of the recent warming of permafrost in Alaska. Journal of Geophysical Research. Vol 112, p1-10.


Schaefer, K., Zhang, T., Bruhwiler, L., Barrett, A. P., 2011. Amount and timing of permafrost carbon release in response to climate warming. Tellus. Vol 63B, p165-180.