ABSTRACT: Variazioni recenti e secolari delle risorse glaciali nelle Montagne Rocciose canadesi: il sistema del Fiume Nelson / Recent and past-century variations in the glacier resources of the Canadian Rocky Mountains: Nelson River system.

CGRG Bibliography of Canadian Geomorphology
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Abstract

In the mid-20th Century, the Park and Front ranges of the Canadian Rocky Mountains contained approximately 1,500 individual glaciers whose melt water drains into the Nelson River system, which flows eastwards and empties into Hudson’s Bay. Using contemporary optical data obtained from space-based imaging sensors, we determined late 20th Century glacier volume changes and related them to river flow volumes. The results reveal significant small-glacier diminution during this period, and provide approximate ice wastage contributions relative to glacier extent. With reference to the results of companion hydrological studies, we suggest that the long-term effect of this glacier contraction has been to reduce the buffering role of glacier-derived melt water during periods when other sources of runoff are in decline – a significant consideration for many water-reliant sectors in this leeward slope, continental region. To place the recent change in context we employed historical vertical aero-photography to characterize the rate of change in glacier extent since the climatic expression of the Neoglacial maximum for the region (c. 1850 AD). Morpho-stratigraphic and geobotanical evidence, and reconstructed and observed glacier mass balance histories are used to further illustrate the nature of these changes. Taken together, it is determined that glacier cover contraction is evolving at an unprecedented pace towards a state not in evidence for several millennia. Both rising temperatures generally and a reduction in glacier nourishment in winter due to a persistent ocean-atmosphere regime shift has fuelled the drastic glacier contraction in evidence recently.

Bibliography of Canadian Geomorphology