Actionable science for sea level rise and coastal flooding: from physical hazards to social resilience

Abstract

Rising sea levels increase the frequency of flooding of all elevations, from minor to extreme, along coastlines across the world. Impacts of flooding, including disasters, have increased the saliency of sea level rise (SLR) and the risks it presents to governments, communities, households and businesses. However, the effect of SLR on coastal flooding is complex and filled with uncertainty, including the effects of natural variability versus human-caused changes on the flood magnitude/frequency relationship. Together, these uncertainties pose methodological obstacles for integrating SLR into flood hazard projections and risk management. They also pose a quandary for decision-makers---how much to invest in building resilience and how soon to act?

A major challenge is how to distill this complexity into information geared towards public and private stakeholders to help inform adaptation decision-making. Because policy windows are limited, budgets are tight, and decisions may have long-term consequences, it is especially important that this information accounts for uncertainty to help avoid damage and maladaptation. Another challenge is that, as decision-makers face difficult choices in planning for programs and infrastructure to increase resilience in the face of these changing hazards, they are doing so with little information about how such policies and other social dynamics affect adaptation among households.

This dissertation includes actionable science to support decision-making for adaptation to coastal impacts, despite uncertainty in projections of SLR and flood frequency. As a result, this body of work applies geoscience, engineering, risk analysis, economics, and psychology to a public policy context. This dissertation is divided into two main parts. The first focuses on flood hazard and provides projections and metrics of change in coastal flooding, accounting for deeply uncertain SLR (Chapters 2 and 3). To help inform city, community, and federal level planners, the second part focuses on social resilience and provides a baseline of how households have adapted to coastal flooding and projections of how they intend to adapt amid other social stressors (Chapter 4). Chapter 5 discusses future work for modeling these coupled physical and human systems to help inform decision-making regarding large-scale protective infrastructure and public policy.