Costs Of Protecting Our Nations Coasts

Table 1 Comparison of This Study's Baseline Data for Vegetated Wetlands (1985) with NOAA Wetlands Inventory Baseline Data NOAA Region (Sites) % of Coast in Sample Wetland Area Sampling Error Wetland Area Northeast (4) Mid-Atlantic (7) ,080 South Atlantic (8) , ,679 Louisiana (7) , ,491 Gulf except LA (14) ,087 1,169 3,608 SW/W Florida (6) , NAb Other Gulf (8) , NAb West (6) United States (46) ,145 2,105 14,723 NA = Not applicable. aAlexander et al. (1986) also estimate the area of tidal flats for several states; we present only the sum of their estimates for vegetated wetlands. bWe have modified the data from Alexander et al. To account for differences in the definition of coastal wetlands for North Carolina. Alexander et al. Include all wetlands in coastal counties regardless of elevation, while Park et al. excluded wetlands above 12 ft NGVD. Because of extensive swamps above 12 ft NGVD in North Carolina's coastal counties, Alexander et al. Found the area of coastal swamps to be 8.4 times the area of marsh, while the boundaries of the sample of Park et al. Found only 1.6 times as much. cStandard deviation of the estimate of the sum (i.e., sample times the square root of the sample size). Source: Alexander, C.E., M.A. Broutman, and D.W. Field An Inventory of Coastal Wetlands of the USA. Rockville, MD: National Oceanic and Atmospheric Administration.

Value of Lost Dry and Wetland By the Year 2100 (billions of dollars) Baseline 50 cm 100 cm 200 cm Wetlands Best Estimate Low High Undeveloped Dry Land Best Estimate Low High Developed Dry Land Used for Building Dikes Best Estimate Low Estimate Note: Calculations are based on the current level of development and on the assumption that currently developed areas protected.

Cost of Protecting Developed Sheltered Shores Through 2100(billions of dollars) Region Baseline 50 cm 100 cm 200 cm Northeast Mid-Atlantic Southeast West United States