Presenting Uncertainty About Climate Change to Water-Resource Managers

Water-resource managers have long strived to meet their goals of system reliability and environmental protection in the face of many uncertainties, including demographic and economic forecasts, intrinsic weather variability, and short-term climate change induced by El Niño and other naturally occurring cycles. Now water managers also face a new uncertainty — the potential for longer-term and more persistent climate change, which, in coming years, may significantly affect the availability of supply and patterns of water demand. Information about the future effects of climate change is deeply uncertain and likely to remain so for the foreseeable future. Thus, the scientific community is debating how to most usefully characterize this important yet uncertain information for decisionmakers. As part of a multiyear study on climate-change decisionmaking under uncertainty, RAND researchers are working with water agencies in California to help them better understand how climate change might affect their systems and what actions, if any, they need to take to address this challenge. This report documents the methods and observations used to preserve an archive of the workshop process and provide a basis for refining the approach for future applications.