Coastal zones are rapidly deteriorating due to intense and increasing human demand. Coastal and nearshore waters and continental shelf areas are a vital source of food, yielding all but 10% of the world's fishing catch. Natural environments important for wildlife conservation are threatened. These resources are threatened by poorly planned and regulated urban, industrial, and agricultural development.
The natural environment of coastal areas, which includes wetlands, estuaries, mangroves and coral reefs, is being degraded by agricultural and urban development, industrial facilities, port and road construction, dredging and filling, tourism and aquaculture. Dam construction, even located far inland, can alter water flow patterns that support important fisheries, as well as cutting off the supply of sediment necessary to maintain deltas and coastlines.
70% of the population live within 80 kilometres of the coastal waters, and almost 50% of the world's cities with populations in excess of one million are near tidal estuaries. In two decades since 1975, the number of people living in coastal Australia outside of the major cities has almost doubled. Coastal engineering and development projects are modifying coastal ecosystems on a very large scale. More than 90% of all chemicals, refuse and other material entering continental shelf and coastal waters remain there in sediments, marshes, mangroves, fringing reefs, mudflats, and other coastal ecosystems. For example, more than 85% of the seagrass meadows in Westernport Bay, Australia, have disappeared since 1974. In the EEC/EU, the use of coastal land for tourist resorts and recreational activities alone was predicted to double between 1990 and 2000, affecting a further 8000 square kilometres along the Mediterranean coast.
More than one-third of the world's population lives within 100 km of a seashore (Cohen and others 1997) - 50 per cent of the population in North America and 60 per cent in Latin America, where 60 of the largest 77 cities lie on the coast. By 2000, nearly 500 million people will be concentrated in urban conglomerations along the shores of Asia (WRI/UNEP/UNDP 1994).
Up to 38 per cent of the African coastline of 40 000 km is considered to be under a high degree of threat from developments which include cities, ports, road networks and pipelines, including 68 per cent of marine protected areas (WRI, UNEP, UNDP and WB 1996, and World Bank 1995a).