1998 Year of the Ocean Impacts of Global Climate Change 



this approach are: (1) improved detection of climate change signals in the ocean; (2) improved 

 models of natural and anthropogenic climate variability; (3) quantification of the predictability of 

 long-time scale climate variability; and (4) reduced uncertainties in CO warming scenarios. 



Global Climate Change Impacts on U.S. Coastal Areas 



The United States' coastline stretches for approximately 158,000 kilometers (93,600 

 miles), bounding some of the most valuable and heavily used areas in the nation that could be 

 affected by climate change. Within these coastal areas lie natural and human resources of 

 tremendous value. These include about 38,900 square kilometers (15,000 square miles) of coastal 

 wetlands, which provide crucial wildlife habitat and filter toxins from rivers, and 6,500 square 

 kilometers (2,500 square miles) of developed barrier islands, which support recreational 

 communities. U.S. coastal areas also support a variety of important economic activities, 

 including fisheries and aquaculture, tourism, recreation, industry, and transportation. 



U.S. coastal areas are experiencing greatly increased pressures as a result of rapid 

 population growth and accompanying development. Nutrient and bacteria pollution from urban 

 and agricultural runoff, changes in hydrology and salinity to naturally balanced systems, shore 

 erosion, and over-development all currently stress our coasts. The effects of climate change 

 would only add to these stresses. 



While global climate has fluctuated throughout time, a global warming scenario could 

 speed this process possibly causing accelerated sea-level rise (ASLR), alterations of rainfall 

 patterns and storm frequency or intensity, and increased siltation. The Intergovernmental Panel 

 on Climate Change (IPCC) has forecasted a rise in global sea level of 5 mm/yr, within the range 

 of uncertainty of 2-9 mm/yr; or 20, 49, or 86 cm by 2100. 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 pattern of chemical 

 and microbiological contamination in coastal areas, and increased coastal flooding. 



Some coastal ecosystems are particularly at risk, including saltwater marshes, coastal 

 wetlands, coral reefs, coral atolls, and river deltas. Other critical coastal resources, such as 

 mangroves and sea-grass beds, submerged systems including submerged aquatic vegetation and 

 mudflats, are at risk from climate change impacts, and exacerbated by anthropogenic factors. 

 Changes in these ecosystems could have major negative effects on tourism, freshwater supplies, 

 fisheries, and biodiversity that could make coastal impacts an important economic concern. 

 Coastal structures, including homes would also be more vulnerable to increased sea-levels. 

 FEMA has estimated that the number of homes in the coastal floodplain would more than double 

 under the highest of sea-level rise scenarios. This growth will be the result of the increase in the 

 area of the coastal floodplain due to sea-level rise, as well as the growth of coastal population, 

 which will increase the number of homes built in the coastal floodplain. 



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