Coastal Defense in an Era of Sea-Level Rise: Science, Politics, and Decision Making

Abstract

Rising mean sea levels due to global warming and other factors are increasing the frequency of coastal flood events. This trend poses a formidable public policy challenge for governments tasked with managing the coastline. Failure to address this issue would continue to put millions of vulnerable people at risk from both cumulative economic losses from minor floods (e.g., high tides) and acute losses from costly and deadly events (e.g., major coastal storms).

Governments up to the task of coastal flood management are confronted with numerous challenges when 1) quantifying future flood risk, 2) designing solutions, and 3) implementing them. Quantifying future uncertainties in relevant physical science parameters, including those that are "deeply uncertain" (either ignorance or disagreement over models used to describe key system processes and probability distributions used to characterize the uncertainty of key variables and parameters) can challenge efforts to quantify present and future risk from coastal floods and can also complicate legacy engineering decision-making for choosing the design heights of coastal flood protection strategies. The latter includes how high to build levees or what elevation to retreat to in order to attain a desired margin of safety. Those pursuing public works to manage coastal floods must also contend with processes constrained by laws and institutions and replete with social conflict between diverse groups, organizations, and communities with heterogenous values, beliefs, interests, and influence. This dissertation examines both of these physical and social science issues across five chapters, each standing alone as its own unique research endeavor.