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The global warming that the world is beginning to experience will likely have a major impact on coastal and marine environments.

• The sea has an enormous capacity to store heat. Warmer water, combined with anticipated changes in ocean currents, could have a devastating impact on marine ecosystems and biodiversity.
• One potential result could be a reduction in the upwelling of nutrients, which would in turn reduce productivity in key fishing areas.
• Decreased growth may also be seen in coral reefs, with high concentrations of CO2 in the water impairing the deposition of limestone required for coral skeletons.

A significant sea level rise is one of the major anticipated consequences of climate change. This will cause some low-lying coastal areas to become completely submerged, while others will increasingly face short-lived high-water levels. These anticipated changes could have a major impact on the lives of coastal populations. The small island developing states (SIDS) will be especially vulnerable to the effects of sea level rise, and to changes in marine ecosystems, because of their major dependence on marine resources.

The extent of future sea level rise will depend on a multitude of factors, and is therefore extremely difficult to predict. While rising sea levels will be exacerbated by thermal expansion of the warming oceans, and the melting of land ice, they will be partially offset by increased precipitation over Antarctica.

The Rising Sea
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The graphic above shows the rises in sea level over the last 300 years and the forecast up to 2100 based on the main scenario models.

Causes of Sea Level of Rises
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The graphic above shows the key components driving rises in sea level based on the A1 Scenario.

Limited information is available on species diversity and the condition of coastal and marine ecosystems. There is growing evidence that many marine species are less widely distributed, and therefore more vulnerable to extinction, than previously thought. The protection and sustainable use of marine resources and biodiversity are governed by several international conventions, including the Convention on Biological Diversity (CBD).

In the CBD framework, sustainable use is defined as "the use of components of biological diversity in a way and at a rate that does not lead to the long-term decline of biological diversity, thereby maintaining its potential to meet the needs and aspirations of present and future generations" (CBD, 2001).

The levelling off of the global fisheries catch reflects a growing decline in most major fishing areas. Today, most fishing areas are producing lower yields than in the past, and it is unlikely that substantial increases will ever again be possible.

Inland and marine aquaculture production grew by about 5% annually during the 1950s and 1960s, by about 8% per year during the 1970s and 1980s, and by some 10% per year during the 1990s.

Most aquaculture is developed in freshwater environments, primarily in Asia. The development of inland aquaculture is seen as an important source of food security in Asia, particularly in land-locked countries.

Species Diversity in the World's Oceans
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The graphic above shows diversity of sepcies in the worlds ocean for marine mammals, sharks, molluscs, birds and shrimps/lobsters

Global Capture Fisheries and Aquaculture Production 1950-1999
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The graphic above shows the trend in the global capture fisheries and aquaculture production between 1950 and 1999.

There are two distinct regions in which coral reefs are primarily distributed: the Wider Caribbean (Atlantic Ocean) and the Indo-Pacific (from East Africa and the Red Sea to the Central Pacific Ocean).

• The diversity of coral is far greater in the Indo-Pacific, particularly around Indonesia, the Philippines, and Papua New Guinea. Many other groups of marine fauna show similar patterns, with a much greater diversity in the Indo-Pacific region.
• Although they possess a smaller number of species the corals of the Atlantic are still unique, with few common species between the two regions.

Mangrove forests cover less than 8% of the global coastline, and comprise of only a few species. Although their distribution is relatively homogenous, there are two distinct regions with completely different floras: the Indian Ocean and the Atlantic Ocean (West Africa and the Americas).

• Similar to corals, the region of greatest mangrove diversity is in Southeast Asia, particularly around the Indonesian Archipelago.
• Mangroves are vital for coastal protection, water purification, and for absorbing CO2, and provide important breeding and nursing grounds for many commercially valuable fish species. Despite their importance, however, mangrove forests are experiencing increasing pressure from timber industries, as well as conversion to agriculture and aquaculture.

There are three distinct areas of seagrass diversity in the Pacific region: the Indo-Pacific (areas around Indonesia, Malaysia, and Papua New Guinea), the seas around Japan, and southwest Australia .

• Seagrass beds cover less than 10% of the world's shallow coastal waters, but are important nursing grounds for commercial fish species. They also provide coastal protection and water purification, absorb CO2, and stabilise sediments.
• Seagrass ecosystems host a rich diversity of species, including threatened species such as dugongs and seahorses.
• Seagrass beds are under threat from dredging for harbours, ports and shipping lanes, fishing by benthic trawling, conversion to aquaculture, coastal pollution, and clearance for beaches and tourist facilities.

Global Coral, Mangrove and Seagrass Diversity
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The graphic above shows the global distribution and diversity of coral, magroves and seagrass.

Physical alteration and destruction of habitats are now considered one of the most important threats to coastal areas. Half of the world's wetlands, and even more of its mangrove forests, have been lost over the past century to physical alterations, with accelerating social and economic development and poor-planning being major causes.

There are currently about one billion people living in coastal urban areas. It is estimated that almost 50% of the world's coasts are threatened by development-related activities. The intense pressure on coastal ecosystems calls for preventive and protective action at all levels: local, national, regional and global.

Unsurprisingly, the coastal areas with the greatest population densities are also those with the most shoreline degradation.

The areas surrounding the Black Sea, the Mediterranean and Southern Asia have the highest proportion of altered land, while the coastal zones of the Arctic, Northeast Pacific, South Pacific, West and Central Africa, East Africa, the Red Sea/Gulf of Aden, and Kuwait have the highest proportions of least modified land.

Human Actions Leading to Coastal Degradation
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The graphic above shows the key factors driving the degradation of estuaries, inter-tidal wetlands and oceans.