IVE SEA LEVEL RISE IN THE UNITED STATES 



Portland, Maine 

 Boston, Massachusetts 

 Newport, Rhode Island 

 New London, Connecticut 

 New York, New York 

 Sandy Hook, New Jersey 

 Atlantic City, New Jersey 

 Philadelphia, Pennsylvania 

 Baltimore, Maryland 

 Annapolis, Maryland 

 Hampton Roads, Virginia 

 Charleston, South Carolina 

 Fernandina, Florida 

 Miami Beach, Florida 

 Cedar Key, Florida 

 Pensacola, Florida 

 Eugene Island, Louisiana 

 Galveston, Texas 

 San Diego, California 

 Los Angeles, California 

 San Francisco, California 

 Astoria, Oregon 

 Seattle, Washington 

 Sitke, Alaska 



Worldwide 



1.2 



144.4 



216.6 



Source: Derivations of historic rates of relative sea level rise due to subsidence are based on an 

 assumption of a 1.2 mm/yr global rise in sea level. Projections are based on mid-low and mid- 

 high estimates from Hoffman et al. 1983, with historic subsidence (from Hicks, Debaugh, and 

 Hickman 1983) added. 



NATURAL IMPACTS OF SEA LEVEL RISE 



There are three major ways by which sea level rise can disrupt wetlands: inundation, 

 erosion, and saltwater intrusion. In some cases, wetlands will be converted to bodies of open 

 water; in other cases, the type of vegetation will change but a particular area will still be wetland. 

 However, if sea level rises slowly enough, the ability of wetlands to grow upward— by trapping 

 sediment or building upon the peat the sediment creates— can prevent sea level rise from 

 disrupting the wetlands. 



In explaining potential impacts of sea level rise, we focus on what the impact would be if 

 wetlands did not grow upward, and leave it to the reader to remember that this potential "vertical 

 accretion" can offset these impacts. The actual impact will depend on the "net substrate 

 change," i.e., the difference between sea level rise and wetland accretion. In this report, all 

 estimates of future wetland loss are based on the assumption that current rates of vertical 

 accretion continue. An important area for future research will be to determine whether future 

 climate change and sea level rise will accelerate or slow the rate of wetland accretion. Even if 



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