| dc.description.abstract |
The proportion of the Earth's land area that is underlain by permafrost, currently
about 25%, is widely anticipated to shrink in response to climate change. Numerous
models have been employed to project potential permafrost distribution into the mid-
to latter 21st century given an expected rise in global temperature. This analysis
complements these efforts by using the temperature at the top of permafrost (TTOP)
model on past and future climate data for the North Slope of Alaska, an area for which
the TTOP has not yet been applied. First, using a climate time-series dataset, trends
in permafrost temperatures were determined for the North Slope from 1901 to 1999.
Relative to the 20th century TTOP mean, mean TTOP for five-year intervals spanning
the entire century remained within 1ºC below or above the mean, although a clear
warming trend was evident from 1986 to 1999. Second, four climate models (HadCM3,
CGCM2, PCM, and CSIRO2) were used to project trends in permafrost temperatures in
the North Slope under the A1FI climate change scenario developed by the Intergovernmental
Panel on Climate Change. All models revealed a clear warming trajectory across the
21st century. The average difference of mean TTOP for five-year intervals spanning
the century against the 21st century TTOP mean was +0.0226 degrees Celsius. Comparing
temperature differences between the latter twenty-five years of both centuries revealed
a relative temperature difference of +1.068 degrees Celsius. This clear warming trend
suggests that under the A1FI scenario, permafrost degradation may occur across the
North Slope, resulting in the probable destabilization of Arctic infrastructure and
ecosystems.
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