Titus J, Hudgens D, Trescott D, Craghan M, Nuckols W, Hershner C, et al. State and local governments plan for development of most land vulnerable to rising sea level along the US Atlantic coast. Environmental Research Letters. 2009;4(4):044008. with supplement
Rising sea level threatens existing coastal wetlands. Overall ecosystems could often survive by migrating inland, if adjacent lands remained vacant. On the basis of 131 state and local land use plans, we estimate that almost 60% of the land below 1 m along the US Atlantic coast is expected to be developed and thus unavailable for the inland migration of wetlands. Less than 10% of the land below 1 m has been set aside for conservation. Environmental regulators routinely grant permits for shore protection structures (which block wetland migration) on the basis of a federal finding that these structures have no cumulative environmental impact. Our results suggest that shore protection does have a cumulative impact. If sea level rise is taken into account, wetland policies that previously seemed to comply with federal law probably violate the Clean Water Act.
This is an important article with detailed maps showing that piecemeal coastal barriers have massive cumulative effect on wetlands, preventing them from migrating inland as sea level rises.