Sea-level rise will increasingly threaten coastal communities. Responses to the issue have generally been grouped into three broad categories: protect, accommodate, and retreat. All three of these strategies will be needed and deployed to varying degrees around the United States. Highly developed areas—think New York City—will require some structural protection. Certain facilities that need to locate on the water may be able to accommodate the rising sea, by being elevated, for example. But in some places around the country, retreating from the shore will be preferred on economic or political grounds.
In a new paper in Climatic Change (note: requires subscription), I explore how shoreline retreat could be managed. Retreat could be left to the market, but there are three reasons this may lead to suboptimal outcomes: (1) unilateral investments in shoreline armoring can harm neighboring properties, (2) coastal ecosystems provide public goods that will be underprovided in the market, and (3) private property owners may not optimally invest and divest in coastal areas because they may not have full information, do not bear the full costs of disasters or inundation, and/or may not accurately perceive risks.
In the paper, I propose a three-part strategy for managed retreat: (1) limit development in the highest risk areas, (2) adopt policies to allow for orderly retreat as inundation occurs, and (3) allow for retreat post-disaster. The nuances and challenges of this three-part approach are discussed in detail in the paper. This post gives a brief overview.
Limiting development in high-risk areas is costly. As such, case-by-case economic analyses will need to be undertaken. There will, however, undoubtedly be areas where development restrictions are justified because (1) ecosystems are providing valuable services that may be lost if not protected; (2) development is a lumpy investment and can be difficult to undo, suggesting that in some areas, limiting development may be preferred; or (3) investors do not have full information about the risks. Identifying what counts as a high-risk area, however, will be contentious and will require transparent and informed designations that are continually reviewed and updated.
Coasts are dynamic environments that are constantly changing, even absent sea-level rise. More flexible property rights, such as rolling easements, have been suggested to allow for private use of the shore until inundation occurs. Such strategies—if they could be adopted—would allow for orderly retreat. Property values would capitalize the eventual abandonment and the beach and coastal ecosystems would be allowed to migrate inland. Many legal issues remain, however, as these approaches have faced challenges in places, such as Texas, where implementation has been attempted. Property owners accepting the notion that their right to a property is not indefinite in the face of sea-level rise is a necessary, and difficult, first step.
Disasters present an opportunity to adopt managed retreat strategies, which will be most effective if discussed and adopted before a disaster hits, rather than in the difficult period of recovery. These policies could involve strategic buyout programs or post-disaster rebuilding requirements. In addition, disaster aid could be reformed to create a greater incentive for local governments to adopt land use strategies that manage risk effectively.
Finally, it is important to not trivialize the political challenges associated with managed shoreline retreat. Climate adaptation is often a “wicked” problem. While it may or may not require changes to formal institutions, it will certainly require changes to the rules and norms governing coastal land use. Such change is notoriously difficult. Scholars of the policy process, however, have noted that disasters can be windows of opportunity for change and that the persistence of “public entrepreneurs” in encouraging the adoption of new policies should not be underestimated.
Retreat will not be optimal everywhere—economically, socially, or politically. But, for places where retreat is desirable, this paper has outlined what managed retreat could look like in the United States. There could be many gains from proactive policy approaches for our shorelines.