Using direct policy search to identify robust strategies in adapting to uncertain sea-level rise and storm surge

G. G. Garner and K. Keller

Environmental Modelling & Software (1 September 2018)

DOI: 10.1016/j.envsoft.2018.05.006

Sea-level rise poses considerable risks to coastal communities, ecosystems, and infrastructure. Decision makers are faced with uncertain sea-level projections when designing a strategy for coastal adaptation. The traditional methods are often silent on tradeoffs as well as the effects of tail-area events and of potential future learning. Here we reformulate a simple sea-level rise adaptation model to address these concerns. We show that Direct Policy Search yields improved solution quality, with respect to Pareto-dominance in the objectives, over the traditional approach under uncertain sea-level rise projections and storm surge. Additionally, the new formulation produces high quality solutions with less computational demands than an intertemporal optimization approach. Our results illustrate the utility of multi-objective adaptive formulations for the example of coastal adaptation and point to wider-ranging application in climate change adaptation decision problems.

keywords: Sea-level rise; Adaptation; Direct policy search; Optimization; Deep uncertainty; Multi-objective

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