These estimates of the nationwide loss of wetlands are based on dozens of assumptions. 

 Nevertheless, they seem to support the simple hypothesis that the area of wetlands today is 

 greater than what would be at the proper elevation for supporting wetlands if sea level rose a 

 meter or two. Thus, if rates of vertical accretion remain constant, a rise of this magnitude in the 

 next century would destroy most U.S. coastal wetlands. 



TABLE 1-7 



PROJECTED U.S. COASTAL WETLAND LOSS AND POTENTIAL GAIN 

 (thousands of acres) 



2100 



* These estimates do not consider the potential wetland creation that could result from possible 

 diversions of the Mississippi River planned and authorized by the State of Louisiana. 

 Source: 1985 inventory from Alexander, Broutman, and Field 1986. Nationwide losses calculated 

 by applying percentages from Table 1-5 to 1985 inventory "Lost" refers to wetlands inundated. 

 "Gained" refers to potential increases in wetland acreage if upland areas are not developed or if 

 development is removed. 



PREVENTING FUTURE WETLAND LOSSES 



Future losses of wetlands from sea level rise could be reduced by (1) slowing the rate of sea 

 level rise, (2) enhancing wetlands' ability to keep pace with sea level rise, (3) decreasing human 

 interference with the natural processes by which wetlands adapt to sea level rise, or (4) holding 

 back the sea while maintaining the marshes artificially. 14 



Society could curtail the projected future acceleration of sea level rise by limiting the 

 projected increases in concentrations of greenhouse gases. Seidel and Keyes (1983) projected 



29 



