Defining and Measuring Coastal Vulnerability and Resilience to Natural Hazards

Abstract:

Accounting for an estimated 23 percent of the world’s population, coastal communities face many types of natural hazards. In particular, they may be vulnerable to the effects of tropical cyclones, flooding due to tsunamis or storm surges, erosion, saltwater intrusion, and subsidence. These coastal hazards are further exacerbated by population growth and climate change. There is a lack of consensus in the literature about what constitutes vulnerability (negative impacts) and resilience (recovery from negative impacts) and how to measure these phenomena. While some important work has focused on the long-term effects of coastal hazards on economic growth, little has been done to understand, in quantitative terms, the extent to which coastal communities may be vulnerable to such hazards and, if so, whether they can be resilient. We surveyed nine indicators of human well-being in order to determine their potential suitability as measures of coastal vulnerability or resilience. Some measures, such as the Gross Domestic Product, the Human Development Index, and the Gini coefficient, comprise economic or distributional indicators of human welfare; others, such as the Social Vulnerability Index, are more complex and difficult to interpret. We selected per capita personal income as the most viable indicator, due largely to its simplicity and its availability over several decades. We used it to examine human community vulnerability and resilience to a specific coastal hazard—significant storm surges from major coastal hurricanes—in several US coastal metropolitan areas. We compiled data on per capita personal income from the US Bureau of Economic Analysis for 15 to 20 years prior and subsequent to four major hurricanes: Hugo, which hit the Charleston, South Carolina, metropolitan area in 1989; Bob, Cape Cod, Massachusetts, in 1991; Andrew, Miami, Florida, in 1992; and Opal, Pensacola, Florida, in 1995. Intervention analysis using linear regression suggests that these coastal areas exhibited the full range of possible combinations of vulnerability and resilience.