Application of the Bottom-up Method on Risk Evaluation of Climate Change in Water Resources System

Traditional approach to evaluate the impacts of climate change on the water resources systems always begins with downscaling general circulation models（ GCMs） and proceeding back to the hydrological model. This approach has some distinct disadvantages： 1） GCM must be downscaled; 2） different GCMs are difficult to be reconciled for a given climate change scenario;3） the uncertainty of GCMs is far from the requirement of the evaluation of climate change impacts. To overcome these limits of the traditional method,a new method termed as ＂bottom-up＂was used for climate risk assessment that linked vulnerability assessment with climate information to assess the risk of climate change impacts on the Quabbin Reservoir,and United States under A2 scenario.The result shows that the risks are around 20% in 2006-2035 and 2036-2055,50% in 2066-2095.