ABSTRACT: Coastal changes.

CGRG Bibliography of Canadian Geomorphology
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The arctic region is undergoing the most rapid environmental change experienced by a large region anywhere on Earth in at least the last 10,000 years, and the rate of change is expected to increase over the coming decades. The coastal zone is particularly vulnerable to climate warming because it is affected by changes in three different systems – the land, the ocean, and the atmosphere. In most parts of the Arctic, the greatest coastal threat from environmental change is an increase in erosion. As permafrost warms, it loses much of its strength and is more susceptible to attack by waves. In addition, warmer sea temperatures melt the ice binding coastal sediments and wash them away. A solid cover of sea ice in winter protects the coast from erosion, but even during the breakup period in the spring or freezeup in the autumn, the presence of ice floes serves to suppress waves. The extent and duration of sea ice has steadily declined in recent years, however, and in 2005, the sea ice cover was the lowest it has been since satellite measurements began in 1978. This trend is expected to continue, and can significantly increase the open water period when wave erosion occurs. In the Canadian Beaufort Sea, for example, open water currently lasts from June to early October (about 120 days), but the duration of open water is expected to increase by 60 days to 150 days. Sea level rise due to the thermal expansion of ocean waters will subject even more land to flooding and erosion, and this is compounded in areas where natural adjustments in the Earth’s crust are already causing coastal submergence. The most rapid coastal erosion occurs as a result of storm surges, when winds force water up on shore, above the height reached by normal tides. Should changing environmental conditions result in more frequent or stronger storms, this process will be intensified. Sediments, soil carbon, and contaminants mobilised by erosion have the potential to create dramatic changes in the geochemistry and biodiversity of the nearshore zone. Physical changes in the coastal zone have differing implications. For instance, many arctic communities are faced with threats to their infrastructure. Duane Smith of the Inuit Circumpolar Conference, says: “Some of our communities are eroding into the ocean in front of our eyes because of the decrease in the multilayered ice, which is allowing for larger storms to roll in.” Erosion at Tuktoyaktuk in wes tern Canada has al ready shifted the coastline more than 100 metres in the last 50 years and is causing the abandonment of a school, houses and other buildings. Substantial resources are being spent on shoreline protection, but residents recognise that they may have to relocate their community. Shishmaref, a community on a small island off the Alaskan coast, is already planning to move to a new site inland, at a cost currently estimated to be between $150 and $180 million. The coastal zone encompasses many important linkages between marine and terrestrial ecosystems (eg shorebirds, geese, mammals, fish and related food webs), which cannot be effectively studied and protected as discrete marine or terrestrial entities. For example, sediment from coastal erosion near Sachs Harbour in Canada appears to affect bottom-dwelling biota. These changes can migrate up the food chain and may explain the decline in fish catches by community residents in recent years. To better under s tand the impact on coastal ecosystems and communities, two projects of the International Arctic Science Committee (IASC), integrate current arctic research in areas such as permafrost, climate change, sea ice, marine geology, and fisheries. Arctic Coastal Dynamics (ACD) has been focusing on improving understanding of physical coastal processes in the circumarctic, while Arctic Coastal Biodiversity (ACBio) has recently developed a science plan that includes assessing and mapping biodiversity. With the IASC arctic coastal biodiversity and coastal dynamics projects, there is now an opportunity to apply the best available physical and biological science to practical goals that serve local human interests and global environmental science and policy.

Bibliography of Canadian Geomorphology