Geomorphological processes in the alpine areas of Canada: the effects of climate change and their impacts on human activities

Abstract

Geomorphological processes are related to climate in a complex manner. Estimates of how processes will react to anticipated climate changes, such as warming and increased precipitation, are necessarily tentative and qualitative. They indicate the kinds of changes that may occur in the alpine landscapes, but not the magnitude or precise rates of such changes. If climate change proceeds as forecast, then one of the most apparent results will be a rise in the timberline. This will result in a decrease in the extent of the alpine zone, thus altering the appearance of many mountain areas and their potential for recreation and tourism. Anticipated changes in snowfall include reduced snow and increased winter rain at elevations close to the present winter snowline, and increased snowfall on higher and colder mountains. This will have a detrimental effect on ski resorts at low elevations, but improve winter access for other activities. Warmer summer temperatures will probably lead to a rise in the summer snowline and significant loss of glaciers, changing the scenery in southern mountain areas, such as Banff and Jasper national parks. Climate change will probably have some hazardous effects. Melting of permafrost and more intense rainfall may initiate or increase the frequency of slides and debris flows in some areas. Heavier snowfall may increase avalanche danger, and glacier recession will probably result in more floods and debris flows due to the failure of glacier and moraine dams. Increased sediment input to glacier-fed rivers may lead to increased channel instability, erosion, and flooding. The hazard zones related to most of these fluvial processes will extend a long way beyond the limits of the alpine zone. Thinner winter snowpacks, rapid spring runoff, and a reduced extent of permanent snow and ice will reduce both the seasonal and longer term water storage capacity of alpine areas. This effect could lead to serious water shortages in regions such as the Okanagan Valley, British Columbia, where summer meltwater maintains extensive agriculture and industry. The impact of climate change on permafrost in alpine areas is not likely to be severe, except possibly in small areas. Warming of ground temperatures will cause a slow reduction in the extent and thickness of permafrost. This will have noticeable effects only where soils contain a high proportion of ice, conditions that are probably not extensive in most alpine areas.