Permafrost

No Thawing of the Cold Permafrost Has Occurred in North ALASKA
During the Last One-half Century
Max C.Brewer, Huijun Jin
(1.Arctic Engineer Emeritus, U. S. Geological Survey Alaska Science Center, 4200 University Drive,
Anchorage, Alaska 99508, USA; Maxcbrewer@yahoo.com; 1-907-561-0336;
2. Professor of Cold Regions Engineering, State Key Laboratory of Frozen Soils Engineering, Cold and
Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, 326 West
Donggang Road, Lanzhou, Gansu Province 730000 China; huijunjin2003@yahoo.com; 86-931-496-7428)
Abstract: Climatic warming has not resulted in measurable thawing of the cold (-6 to -10°C)
permafrost in Northern Alaska during the last one-half century. The maximum depths of
summer thaw at five locations near Barrow, Alaska, in 2005 were within the ranges of the
depths obtained at those exact same locations during the early 1950s. However, there has been a
net warming of about 2°C at the upper depths of the permafrost column at two of the locations.
Thawing of permafrost (increase in active layer thickness) is determined by the summer
thawing index for the specific year, while any warming, or cooling, of the upper permafrost
column results from the cumulative effect of changes in the average annual air temperatures
over a period of years, assuming no change in surface conditions. The reported shoreline
erosion along the Northern Alaskan coast is a secondary result from changes in the nearby
ocean ice coverage during the fall stormy period, and not directly because of any climatic
warming of the permafrost.
Key words: cold permafrost, climatic warming, thawing index, Northern Alaska.
Relationship between Permafrost and Past Ice
Cover on the Qinghai-Tibet Plateau
Michelle Koutnik 1 , Ronald S. Sletten 1 , Bernard Hallet 1 , and Shawn Marshall 2
(1.University of Washington, Department of Earth and Space Sciences, Box 351310, Seattle, WA, 98195
USA; 2.University of Calgary, Department of Geography, Calgary, Alberta, Canada)
Abstract: The degree to which the Qinghai-Tibet Plateau was covered by ice during the last Ice
Age is still debated. The evidence for complete glaciation competes with that for only relatively
minor mountain glaciation, where vast regions of the plateau remain ice-free. The argument is
primarily based on the geomorphic record. However, we anticipate that the present
distribution and depth of permafrost could further elucidate the problem.
Permafrost is a sensitive responder to surface temperature forcing. This has been seen
during the past century with the rapid degradation of permafrost due to climate warming across
the Tibetan Plateau as well as other permafrost regions. Ground temperature profiles have
proven to be valuable archives of surface temperature and may provide one of the most robust
indicators of surface warming. In addition to using temperatures, permafrost distribution is
likely to integrate past changes in surface conditions.
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