Informing water management decisions under conditions of deep uncertainty and non-stationarity [INVITED]

Water managers increasingly recognize that for the purpose of evaluating future investments and operational plans it is no longer in general reasonable to assume that future climate will resemble past climate. However this "non-stationarity" of future climate presents water managers with a difficult planning challenge because the speed, characteristics, and seriousness of future changes remain deeply uncertain. This talk will present results from a series of analyses and workshops where we have used: i) a variety of sources of information about future climate, including down-scaled projections from climate models and paleoclimate analogues, to identify the vulnerabilities of agencies' water management plans and to assess options for reducing those vulnerabilities and ii) survey methods and laboratory psychology experiments to evaluate the best means to communicate actionable, yet uncertain, information to the policy-makers and stakeholders involved with water planning. The analysis employs Robust Decision Making (RDM) methods, a new quantitative decision- analytic approach for supporting decision under conditions of deep uncertainty, in which we use simulation models to assess the performance of agency plans over thousands of plausible futures, identify those futures where the plans fail to perform adequately, use cluster finding algorithms to summarize these vulnerable futures in a small number of policy-relevant scenarios, and use these scenarios to help decision makers understand the vulnerabilities of their plans and assess the options for ameliorating these vulnerabilities. We are currently working with several large U.S. water agencies to help integrate this approach to climate vulnerability and response option analysis into their planning and to help communicate the results to their constituencies. This RDM approach may prove a widely useful decision framework for hydrologic and other analyses in support of water management in an uncertain, changing environment.