Regional Results 



Armentano et al. emphasize that their estimates should not be considered as statistically 

 valid estimates of wetland loss in particular U.S. coastal regions. Nevertheless, we believe that the 

 results provide a useful and indicative first approximation. 



Table 1-5 summarizes their estimates for the low and high sea level rise scenarios. The first 

 two columns of the bottom half show their estimates of the wetiand loss that would take place if 

 development prevented new marsh from forming inland. The other two columns show their 

 estimates of the net change in wetland acreage assuming that development does not prevent new 

 marsh from forming except where the shoreline already has bulkheads, levees, or other shore 

 protection structures. These assumptions are both extreme. Complete protection of all existing 

 dry land would be very unlikely, as would a total abandonment of all (currently) unprotected areas 

 just inland of the wetlands. The extent to which development retreats would depend both on 

 economics and on public policies regarding the appropriate level of wetland protection in the 

 face of rising sea level. An investigation of these issues, however, was outside the scope of that 

 study. 



TABLE 1-5 



SAMPLE CHANGES IN COASTAL WETLANDS: 1975-2100 



2100 



REGION 



Wetland Area (square kilometers) 



New England 

 Mid Atlantic 

 South Atlantic 

 Florida 



N.E. Gulf Coast 

 Mississippi Delta* 

 Chenier Plain, Tex 

 Californian Prov. 

 Columbian Prov. 



TOTAL 



4846 



2928 



1161 



3779 



2014 



Percent Loss (gain) 



New England 

 Mid Atlantic 

 South Atlantic 

 Florida 



N.E. Gulf Coast 

 Mississippi Delta* 

 Chenier Plain, Tex 

 Californian Prov. 

 Columbian Prov. 



TOTAL 



■40 



■76 



-22 



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

 possible diversion of the Mississippi River. 



Source: 1980 data from Appendix 4-A; 2100 data from Table 4-8 of Armentano et al. (Chapter 4). 



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