CLIMATE-CHANGE - NUMERICAL MODELING OF SEDIMENTATION AND COASTAL PROCESSES, EASTERN CANADIAN ARCTIC

We use three sequential ''water-sediment transport'' numerical models to evaluate changes in fluvial sediment outputs for two near-future co ntrasting climate-change scenarios (warmer summers or warmer and moist er winters) for the eastern Canadian Arctic. Our integrated model gene rates values for deposition into a fiord basin. The effects of climate warming are imposed on 200-yr fluctuations in relative sea level (bas e level) that in turn have a long-term forcing associated with late Qu aternary glacial unloading. Thus some areas are submerging (around the periphery of the former ice sheet) and others are emerging (inland at the heads of fiords). Small, short-term changes in sea level may invo lve meltwater supply to the world ocean from the melting of glaciers a nd ice sheets, and sea water expansion with a warming ocean. Alternati vely, large ice sheets may also thicken over the short term (200 yr), thereby withdrawing water from the global hydrological cycle. Both cli mate scenarios result in an increased sediment flux over the next 200 yr. However, warmer summers will have the largest impact by (1) causin g ice caps to melt, (2) inducing more expansive and turbid river plume s, (3) increasing progradation of the coastline into the sea, (4) rais ing relative sea level, and by (5) increasing the number and size of t urbidity currents generated off river mouths: Warmer and moister winte rs that may lead to deviations from these impacts include (1) growth o f ice caps, (2) fall of relative sea level, (3) stability of coastline s as increased sediment delivery keeps pace with changes in regional r elative sea level, and (4) fewer basin turbidity currents, as more of the bedload is trapped on top of sandur surfaces.