Climate change impacts on the hydrology of the Great Lakes-St. Lawrence system

A review of the current state of knowledge on climate change due to an 'enhanced greenhouse effect' and the response of the climate and hydrologic systems to a changing atmosphere is provided. In particular, the survey presents historic trends in and the impacts of climate change on temperature, precipitation, evapotranspiration, runoff and Great Lakes levels. While much of the impacts research in the Great Lakes-St. Lawrence basin has used equilibrium 2×CO2 scenarios, the transient scenarios for 2030 and 2050 from the Canadian Centre for Climate Modelling and Analysis and the United Kingdom Hadley Centre coupled atmosphere-ocean global circulation models are also described. If the significant declines in runoff and lakes levels suggested by climate change scenarios are realized, there could be serious supply-demand mismatches and water allocation issues. The issue of climate change reinforces the need for continued cooperative planning and management of the water resources of the Great Lakes-St. Lawrence basin.