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Polar Amplification of Global Warming
Polyakov, I.V., Alekseev, G.V., Bekryaev, R.V., Bhatt, U., Colony, R.L., Johnson, M.A., Karklin, V.P., Makshtas, A.P., Walsh, D. and Yulin A.V. 2002. Observationally based assessment of polar amplification of global warming. Geophysical Research Letters 29: 10.1029/2001GL011111.

A long succession of climate models has consistently predicted that CO2-induced global warming should be significantly amplified in earth's polar regions and that the first signs of man's expected impact on the world's weather should thus be manifest there. Long-term temperature records, however, tell a vastly different story.

What was done
The authors used "newly available long-term Russian observations of SAT [surface air temperature] from coastal stations, and sea-ice extent and fast-ice thickness from the Kara, Laptev, East Siberian, and Chuckchi seas" to gain new insights into trends and variability in the Arctic environment poleward of 62N.

What was learned
Throughout the 125-year Arctic air temperature history they developed, the authors identified "strong intrinsic variability, dominated by multi-decadal fluctuations with a timescale of 60-80 years;" and because of this fact, they found temperature trends in the Arctic to be highly dependent on the particular time period selected for analysis. In fact, they found they could "identify periods when [A]rctic trends were actually smaller or of different sign [our italics] than Northern Hemisphere trends." Over the bulk of the 20th century, however, when they say "multi-decadal variability had little net effect on computed trends," the temperature histories of the two regions were "similar" and did "not support amplified warming in polar regions predicted by GCMs." Also like the temperature trend, the ice cover trend was "smaller than expected," with fast-ice thickness trends "relatively small, positive or negative in sign at different locations, and not statistically significant at the 95% level."

What it means
In the words of the authors, real-world data -- which are the final arbiters of all debates and in the case of the current study come from the Arctic -- "do not support the [IPCC] hypothesized polar amplification of global warming." We also note, in this regard, that the same would appear to be true of data from the planet's south polar region, where the Antarctic continent has actually been cooling for at least the last three and a half decades (see our Journal Reviews Thirty-Five Years of Climate Change in Antarctica and Recent Trends in Antarctic Surface Temperatures). Hence, it is abundantly clear that one of the most highly-believed predictions of essentially all climate models employed by the IPCC is just plain wrong.

Reviewed 5 March 2003