Relocation, Retreat, and Rising Sea Level

Florida’s beaches and tropical climate make it an attractive place to live and visit. But like many coastal areas around the world, Florida is increasingly subject to flooding—the kind of flooding that’s so unmanageable it prompts people to move away. In the coming years, climate change is projected to exacerbate flooding due to storm surges, increasing precipitation intensity, and rising sea levels that increase tidal flooding. As more people experience damages and consider moving, the communities they leave and move to will be affected. But, there is little research on the projected timing and pattern of this migration to guide planners and decision-makers.

A new study led by Yong Jee Kim (PhD 2019) of the Korea Environment Institute and Purdue graduate advisors Juan Sesmero and Brigitte Waldorf (Department of Agricultural Economics) addresses this research gap. The researchers found that in the years following a major flood, households with high perceived flood risk are more likely to move from their homes, and that the destination of those that do move varies in systematic ways by income and race.

The research team focused their analysis on Escambia County, the westernmost and oldest county in Florida, and an area that experienced two major floods, one in 2012 and another in 2014. Using annual property tax records, the researchers estimated the migration patterns of homeowners between the years 2010 – 2016. They then used this analysis to simulate what could happen as sea level rises.

Record-breaking rainfall in Escambia County in April 2014 caused flooding that led to a federal disaster declaration for the area. In the two years following the 2014 flood, households with high perceived risk of flooding (as measured by home insurance relative to the home value) were more likely to move. However, households that made the decision to move tended to relocate to a new residence in close proximity to their previous home—and with a similar exposure to flooding. This preference for short distance moves was strongest for Black homeowners. In addition, the preference became stronger with a household’s increasing financial security, perhaps reflecting greater ability to afford higher insurance premiums.

Sea level rise is a slow and gradual process, and to date, most migration away from areas exposed to sea level rise has been voluntary. FEMA has been buying vulnerable properties to encourage relocation away from flood-prone areas since 1993, but, most of the agency’s attention has focused on helping communities rebuild, not relocate. Even in the aftermath of 2012’s Hurricane Sandy, only 300 out of more than 10,000 damaged homes were acquired, and the Governor’s Office of New York produced a series of public service announcements seeking donations to help the state rebuild.

In the US an estimated 127 million people—nearly 40% of the population—live in coastal counties where flooding and storm hazards are projected to grow. This work by Kim and colleagues suggest that individual households making reactive decisions on retreating from rising waters will in fact stay close to the hazard-prone areas, and will likely need to move again. According to the 2018 National Climate Assessment, in all but the lowest possible sea level rise projections, “retreat will become an unavoidable option in some areas of the U.S. coastline.” This study supports the case for proactive, strategic and managed retreat from rising waters— the preemptive movement of people and property away from areas experiencing severe impacts—effectively reducing risk by reducing exposure, and thereby avoiding preventable and recurrent disaster payments borne by taxpayers.

 

Kim, Y.L, Waldorf, B., Sesmero, J. 2020. Relocation, Retreat, and the Rising Sea Level: A Simulation of Aggregate Outcomes in Escambia County, Florida. Region et Developpement 51, 31-43. (PDF)