1998 Year of the Ocean Impacts of Global Climate Change 



treatment discharges. About 40 percent of over 20 million acres of shellfish-growing waters in 

 estuaries are "harvest-restricted," i.e., commercial harvest is either prohibited or limited, due 

 primarily to bacterial contamination from urban and agricultural runoff and septic systems. In 

 addition, the effects of pollution, as well as changes in salinity and hydrology have contributed to 

 the loss of traditional shellfish acreage that can no longer support shellfish along U.S. coasts. 

 These changes would be exacerbated by climate change. During 1996, at U.S. ocean, bay, and 

 Great Lakes beaches, there were at least 2,596 individual closings and advisories, 16 extended 

 (6-12 weeks) closings and advisories, and 20 permanent (over 12 weeks) closings and advisories. 

 Including the days of extended closings, the total comes to over 3,685 closings and advisories 

 (NRDC, 1997). U.S. shorelines are undergoing erosion from sea-level rise, natural retreat of 

 headlands, coastal structures, and modifications to the natural flow of rivers. 



Human activities from further inland can also have a deleterious impact on coastal 

 resources. Effluent discharges from sewage and industrial plants, as well as agricultural run-off, 

 have caused significant nutrient over-enrichment in many coastal waters. Sewage and siltation 

 can be significant causes of coral reef and other coastal system degradation in Hawaii and 

 Florida. Dams, irrigafion projects, and other water control efforts have affected coastal 

 environments by diverting or altering the supply of water, sediment, or nutrients to a naturally 

 balanced ecosystem. 



Intensive residential and commercial development of coastal areas, particularly dynamic, 

 storm-prone areas such as barrier islands, puts life and property at risk and creates substantial 

 financial liabilities. For example, there are currently an estimated 276,000 households located in 

 high-hazard areas threatened by storm surge, and an additional 2.4 million households located in 

 the flood plain adjacent to this high-risk zone. In addifion, between 1970-89, almost half of all 

 new residential, commercial, and industrial construction occurred in coastal counties and was not 

 always built to standards to withstand major storms. Infrequent, yet high intensity storms that 

 impact coastal areas, in conjunction with poor construction, can result in billions of dollars of 

 damages, particularly where development occurs in low-lying areas. The cost of damage from 

 Hurricane Andrew (in Florida and Louisiana) was $25 billion, and the combined costs for 

 Hurricanes Hugo (South Carolina), Opal (Florida), and Fran (North Carolina) totaled $3 billion. 

 While a majority of damage from these storms was due to poor construction of infrastructure and 

 buildings, costs from coastal storms could be reduced or prevented by making better decisions 

 about the location and type of development in coastal areas. 



Key Strategic Issues Concerning Coastal Areas and Climate Change 



Throughout time, climate change has affected the coastal environment and will continue 

 to do so in the future. However, human activities and alterations have rendered coastal resources 

 more vulnerable to climate change-induced processes, such as accelerated sea-level rise, 

 alterations of rainfall patterns and storm frequency or intensity, and increased siltation. Climate 

 change and a rise in sea level or changes in storms or storm surges could result in the increased 

 erosion of shores and associated habitat, increased salinity of estuaries and freshwater aquifers, 

 altered tidal ranges in rivers and bays, changes in sediment and nutrient transport, a change in the 



G-25 



