Decision-scaling for Robust Planning and Policy under Climate Uncertainty World Resources Report Uncertainty Series

According to conventional wisdom, planning for the future is becoming more difficult due to anthropogenic climate change. As the story goes, it is possible that a plan may be made anticipating one climate future and then disaster results when another future climate unfolds. In practice, it is often possible to assess risks and develop robust strategies that arise due to climate uncertainties through a systematic approach to analysis of the decision at hand. However, there is currently a lack of methodology for gleaning decision-relevant information from the spectrum of available projections of the future. In this paper a methodology is described for planning under climate uncertainty and for the development of robust adaptation strategies. In the case of climate change, where the future is deeply uncertain and there is a vast array of data relating visions of the future, the usual approach to science-based decision making may not be effective. In the usual sciencebased approach, attempts are made to reduce the uncertainty of the future and planning is based on some best guess of the most likely scenario. The approach described here relies on a fundamental reversal of the usual focus of science-based decision making, that is, the quest to reduce uncertainty and select an optimal plan for the likely future. The underlying philosophy is one of accepting irreducible uncertainty and identifying strategies that will perform well over a wide range of climate futures.