Vulnerabity, sensitivity, and adaptability of Columbia Basin water resources to natural and anthropogenic climate change

The University of Washington's Climate Impacts Group has examined the consequences of natural climate variability and projected future climate change for the natural and human systems in the Pacific Northwest. Here, we examine the sensitivity, adaptability and vulnerability of hydrology, water resources, and the water management systems in the Columbia River Basin. Empirical evidence shows that the Columbia Basin water resources system (the hydrosystem) is sensitive to climate variability, especially with respect to drought. Management inertia and the lack of a centralized authority coordinating all uses of the resource impede adaptability to drought and optimization of water distribution. Addressing the climate-related vulnerabilities of the water resources system is impeded by the high level of conflict between competing water uses. Regional climate change projections based on Intergovernmental Panel on Climate Change (IPCC) scenarios and output from streamflow and hydrosystem simulation models suggest exacerbated conflicts between users as a result of a predicted significant decrease in summertime streamflow in future years. An understanding of the patterns and consequences of past climate variability, impacts and policy responses is crucial to developing an adequate response to future changes in climate.