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Preface Annex 1
CHAPTER 5: COASTAL AND MARINE ENVIRONMENTS
Lead Authors: Russell Arthurton, Kwame Korateng
As coastal populations in Africa continue to grow, and pressures on the environment from land-based and marine human activities increase, coastal and marine living resources and their habitats are being lost or damaged in ways that are diminishing biodiversity and thus decreasing livelihood opportunities and aggravating poverty. Degradation has become increasingly acute within the last 50 years (Crossland and others 2005). Arresting further losses of coastal and marine resources, and building on opportunities to manage the resources that remain in a sustainable way, are urgent objectives.
The main causes of this degradation, apart from natural disasters, are poverty and the pressures of economic development at local to global scales. Economic gains, many bringing only short-term benefits, are being made at the expense of the integrity of ecosystems and the vulnerable communities that they support. The overexploitation of offshore fisheries impacts on the food security of coastal populations. Another key concern is the modification of river flows to the coast by damming and irrigation, and pollution from land, marine and atmospheric sources (Crossland and others 2005).
Africa’s coastal and marine areas also have important non-living resources. There are offshore commercial oil and natural gas reserves in some 20 countries and many of these are being developed to supply the global energy market as well as domestic needs (EIA 2005). Many countries in Western Africa, for example, are oil producers, with Cameroon, Gabon and Nigeria being net exporters. Alluvial diamond- and heavy mineral-bearing sands have long been worked from the coastal sediments of Southern Africa. Exploitation of these non-living resources has damaged the coastal environment and, in the case of oil production in the Niger delta, caused civil conflict.
Africa’s coastal environment is becoming an increasingly attractive destination for global tourism. In some countries, especially the small island developing states (SIDS), tourism, and its related services, is a main contributor to national economies (WTTC 2005).
Most countries recognize the value of their coastal and marine biodiversity and have gazetted marine and wetland protected areas to ensure their sustainability (UNEP-WCMC 2000). The protection and restoration of Africa’s coastal and marine ecosystems and their services are long-term objectives for local to global communities. These objectives must be achieved in the face of the pressures from land-use change, including urbanization, and climate change, including the rising sea level, coastal erosion and lowland flooding (IPCC 2001). This demands policy approaches that are multisectoral and occur at multiple levels; such approaches are discussed in Chapter 8: Interlinkages: The Environment and Policy Web.
OVERVIEW OF RESOURCES
Africa’s mainland and island states have rich and varied coastal and marine resources, both living and non- living. The coasts range from deserts to fertile plains to rain forest, from coral reefs to lagoons, and from high- relief, rocky shores to deeply indented estuaries and deltas. Their marine environments include the open Atlantic and Indian oceans and the almost landlocked Mediterranean and Red seas. Continental shelves, where waters are less than 200 m deep, in some places extend more than 200 km offshore, while elsewhere they are almost absent.
The biodiversity of the coastal zone is an important resource and there are many designated protected areas, both wetland and marine. The coral reefs, sea- grass beds, sand dunes, estuaries, mangrove forests and other wetlands that occur around many shores provide valuable services for humanity, as well as crucial nursery habitats for marine animals and sanctuaries for endangered species. The coral reefs, sea-grass beds, sand dunes, estuaries, mangrove forests and other wetlands that occur around many shores provide valuable services for humanity, as well as crucial nursery habitats for marine animals and sanctuaries for endangered species (Figure 1). LMEs are relatively large regions, in the order of 200 000 km² or greater, characterized by distinct bathymetry, hydrography, productivity, and trophically dependent populations (Sherman and Alexander 1986). Many of these LMEs are characterized by seasonal or permanent coastal upwellings of cold, nutrient-rich oceanic water (where water is forced upwards from the ocean depths to the surface) supporting important fisheries.
During the last decade or so, substantial oil and natural gas resources have been discovered offshore, some of them in deep or ultra-deep water on the continental slope, as in Western Africa (EIA 2005) (Figure 2). Many offshore areas remain unexplored. The largest of the new oil reserves are those off the Niger delta, itself a globally important, established production area. Other major oil reserves have been discovered and are being developed within the Exclusive Economic Zones (EEZs) of Cameroon, Equatorial Guinea and Angola. Many oil reserves are associated with natural gas. Large reserves of non- associated gas have been discovered offshore around the Gulf of Guinea – notably in Nigeria – and off Namibia and South Africa; also in the Mediterranean in the Gulf of Gabès and off the Nile delta. Natural gas is in production off the Tanzanian mainland.
Many of the coastal sediments of Southern and Eastern Africa yield mineral resources. The coastal sand dunes and seabed sediments along the Atlantic shores of South Africa and Namibia contain commercially valuable alluvial diamonds, while coastal sediments on South Africa’s Indian Ocean shores and in Mozambique contain commercial titanium and zirconium minerals. Coastal sands in Kenya are also a source of titanium.