CGRG Bibliography of Canadian Geomorphology
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Author : Allard, M.; Fortier, R.; Duguay, C.; and Barrette, N.
Date : 2002.
Title : A trend of fast climate warming in northern Quebec since 1993. Impacts on permafrost and man-made infrastructures.
Publication : American Geophysical Union 2002 Fall Meeting, Moscone Center, San Francisco, California, 6-10 December 2002.
Issue :
Page(s) :
Abstract
From about 1945 to the early 1990s,the climate of the Ungava Peninsula and Ungava Bay area followed a cooling trend that was documented both in Environment Canada's stations and in permafrost temperatures measured with thermistor cables spread across the region. This trend was also invoked to explain the observed increase of ice-wedge cracking and the thinning of the active layer. Despite some logistical difficulties, continued monitoring of permafrost temperatures in many communities now document a radical change of trend. In summer, the warming trend began in 1993 while winters started to become warmer in 1995. Winters 1997-1998 and 1998-1999 were particularly warm. The temperature increases at climatic stations such as Kuujjuaraapik and Kuujjuaq are unprecedented in the instrumental record. In the continuous permafrost zone, this recent and fast warming is translated into the shifting of permafrost temperature profiles by as much as 1.9$°$C at depths down to 20 m and into an important increase in active layer depth. A smaller number of ice wedges are now apparently active. In the discontinuous zone, palsas in particular are degrading and thermokarst landscape in wetlands is expanding. As a result of the fast climate change, one dimensional thermal modelling suggests that permafrost thickness in the discontinuous zone is now greater than what it should be at equilibrium with present atmospheric temperatures. On some of the monitoring sites, an increase in snow cover thickness was probably also a contributing factor; precipitation data, however, are insufficient to assess that factor at the regional scale. One active layer slide provoked the moving of 20 houses in a community. Signs of thaw settlement under roads and airstrips are gradually showing up. Continued monitoring will determine coming trends and variations.
Bibliography of Canadian Geomorphology