Climate change and permafrost stability in the eastern Canada Cordillera: The results of 33 years of measurements

Over the last 33 years, a network of climate stations has been set up at high altitude mountain permafrost sites from Plateau Mountain near Claresholm, Alberta, north to Sheldon Lake on the North Canol Road in the Yukon. Taken together with the data from the US National Weather Service and the Canadian Atmospheric Environment Service, the results indicate a cooling of mean annual air temperature south of Calgary, no significant change in Calgary, a slight warming at Jasper, and a major warming at Summit Lake, west of Fort Nelson. In contrast, the south eastern and central Yukon show only a minor warming trend that lies well within the limits of a sixty-year record measured by the Canadian Atmospheric Environment Service. Along the Mackenzie valley and on the North Slope of Alaska, the mean annual air temperature is rising. Permafrost is aggrading on Plateau Mountain,degrading at Summit Lake, and appears to be stable in southern Yukon and southern Alaska. This is in contrast to the warming occurring on the Arctic coastal plain and along the Mackenzie valley. It therefore appears that changes in climate vary considerably from place to place, and even where warming may occur, it may not continue indefinitely. There has been a northward shift of the arctic front due to a weakening of air pressure in the Yukon and Alaska relative to the continental tropical (cT) and maritime polar (mT) air masses to the south. Any actual changes that may be occurring appear to undergo amplification along the Mackenzie valley and Arctic coastal plain and reduction by buffering in the interior Yukon and Alaskan mountains, a result of micro-environmental factors. Continued, careful monitoring of the climate is required and needs to be expanded in the National Parks in the mountains in order to provide data on the changes that may be taking place. Such measurements can provide a sound basis for interpreting ecological and other climate-related data. The existing climate models are not working satisfactorily because we do not know enough about the causes and processes involved in climate change. Improved results can indicate where best to site structures such as pipelines so as to minimize maintenance costs. Models may also help explain why certain areas such as Beringia, which saw reduced climate change, acted as important refugia during the glaciations.

作 者： Stuart A. Harris   作者單位： Department of Geography, University of Calgary, Canada T2N 1N4  刊 名： 寒旱區(qū)科學(xué)（英文版）  英文刊名： SCIENCES IN COLD AND ARID REGIONS  年，卷(期)： 2009 1(5)  分類(lèi)號(hào)： P5  關(guān)鍵詞： permafrost   stability   long-term measurement   climate change   the Eastern Canada Cordillera  

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