ABSTRACT: Permafrost and climate change, Garry and Richards islands, western Arctic coast, Canada.

CGRG Bibliography of Canadian Geomorphology
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Abstract

The outer Mackenzie delta area contains two principal terrain types: regularly flooded ground that is part of the delta itself, and Pleistocene tundra uplands. The ground temperature regime of the delta is distinct from the regime in the uplands. In 1974, J.R. Mackay published a baseline map of near-surface ground temperatures for the region, which records conditions in the late 1960s and early 1970s. Since 1970, the region has undergone climate warming at a rate of 0.74ºC/decade, for a total increase in temperature of 2.5ºC. The temperature signal is consistent from Komakuk Beach, near the Alaska border, to Cape Parry, and southwards to Norman Wells. Since 1998, ground temperatures have been measured on Garry and Richards islands in order to compare present conditions with those reported 30 years ago. On Garry Island, and at the Illisarvik experimental drained-lake site on Richards Island, the thermal regime of the upper 12 m of the ground has been measured throughout the year. At both sites the mean annual ground temperature is about 1.5ºC higher than in the late 1960s. Similarly, measurements of temperature at 1-m depth recorded by miniature data loggers indicate that the mean annual temperature is now between -6.5ºC and -7ºC at sites where it was between -8ºC and -9ºC thirty years ago. The increase in ground temperature is less than the increase in air temperature because (1) curvature in the ground temperature profile implies that heat from the surface is now probably warming ground at depth and (2) the warming is driven by changes in winter temperature, when the surface is buffered from the atmosphere by the snow cover.

Bibliography of Canadian Geomorphology