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Oceans and Coastal Areas

Coral reefs under pressure

In addition to the short-term threat represented by coral bleaching, coral reefs are under pressure from a variety of human impacts. The accelerating decline of coral reef ecosystems is described in the latest global assessment of the Status of Coral Reefs of the World: 2000 (Wilkinson, 2000). It details the continuing deterioration of coral reefs in all areas where human activities are concentrated, notably along the coast of eastern Africa, all of continental South Asia, throughout Southeast and East Asia and across the wider Caribbean region.

It shows that by late 2000, 27% of the world’s reefs have been effectively lost, with the largest single cause being the massive climate-related coral bleaching event of 1998. This destroyed about 16% of the coral reefs of the world in 9 months during the largest El Niño and La Niña climate changes ever recorded. While there is a good chance that many of the 16% of damaged reefs will recover slowly, probably half of these reefs will never adequately recover. These will add to the 11% of the world’s reefs already lost due to human impacts such as sediment and nutrient pollution, over-exploitation and mining of sand and rock and development on, and ‘reclamation’ of, coral reefs.

The extent of world-wide degradation of reefs was first documented by a global survey undertaken by Reef Check 1997 (http://www.ust.hk/~webrc/ReefCheck/summary.html). Many coral reef fisheries resources are being pushed towards extinction everywhere by heavy over-exploitation, and habitat degradation from land-based activities and runoff is widespread on inhabited coasts.

A World Atlas of Coral Reefs, prepared by the United Nations Environment Programme World Conservation Monitoring Centre (UNEP-WCMC) provides a new global estimate for coral reefs world-wide: 284 300 sq km, an area just half the size of France. For the first time, it also provides reef area estimates for individual countries and includes detailed maps and statistics for all the world's coral reef nations (UNEP, 2001).

The first global assessment of coral reefs to map areas at risk from overfishing, coastal development and other human activity (Bryant et al., 1998), shows threats to 58 percent of the world's coral reefs. A third of all reefs are threatened by overexploitation, and a third also by coastal development. At least 11 percent are "hot spots" with high levels of reef fish biodiversity that are under high threat from human activities, including Philippine and Indonesian reefs, Tanzania and the Comoros along the East African coast, and the Lesser Antilles in the Caribbean. In Southeast Asia, more than 80 percent of the most species-rich coral reefs on earth are threatened by coastal development and fishing pressures, and over half are at high risk. Nearly two thirds of Caribbean reefs are in jeopardy, especially around islands like Jamaica, Barbados and Dominica. Pacific reefs are the least threatened, with only 40 percent at medium or high risk of damage. While there are over 400 marine parks and reserves with coral reefs, most are very small, and at least 40 countries have no protected areas for their coral reefs (http://www.wri.org/wri/indictrs/reefrisk.htm).

Another concern is the recent discovery that coral reefs are threatened by rising levels of carbon dioxide in the atmosphere, which may lower calcification rates of corals, coralline algae and coral-algal communities by up to 10-20 percent as carbon dioxide levels double in the next century. (Coral Reefs and Global Change,1998) This will make it harder for them to build their skeletons and add to the reef. Other estimates suggest that the increase in atmospheric CO2 will reduce carbonate ion concentration in the surface ocean by 30percent and cause a potential reduction in coral growth over the next 65 years of 40 percent (Langdon, 2000).

More general information on the status of coral reefs is available from the NOAA Coral Health and Monitoring Project at http://coral.aoml.noaa.gov/.

In response to these threats, the UNEP Coral Reef Unit was established in December 2000 within the Division of Environmental Conventions, in close collaboration with the Division of Early Warning and Assessment and the UNEP World Conservation Monitoring Centre, and is helping to lead international efforts to save the planet's threatened coral reefs. It works actively with international partners around the world to increase international, national and local support for coral reef conservation and sustainable use. It is responsible for UNEP's participation in the International Coral Reef Action Network (ICRAN) which is leading action to reverse the decline in coral reefs, build consensus and public awareness on principal causes of coral stress, and improve coordination, integration and delivery of practical information, assistance and training on coral reef management. Through assessment, awareness-raising, training and demonstration projects in four Regional Seas (the Caribbean, Eastern Africa, East Asia and the South Pacific), ICRAN will catalyse action worldwide. ICRAN is an initiative of several global organizations active in coral reef conservation and sustainable use, supported by the United Nations Foundation. Data and reports on monitoring and assessment projects on coral reefs are used to communicate coral reef information to ICRAN partners, other key stakeholders, scientists and policy makers.

There is scope for wider collaboration among UN system partners on coral reffs. Working Party members may wish to inform the meeting of any activities related to coral reef protection in which they are involved and to determine the need for further concerted action in this field.

References

Bryant, Dirk, Lauretta Burke, John McManus and Mark Spaulding. 1998. Reefs at Risk: A Map-Based Indicator of Threats to the World's Coral Reefs. WRI/ICLARM/WCMC/UNEP. World Resources Institute, Washington, D.C., 1998 56 p. Web version: http://www.wri.org/wri/indictrs/reefrisk.htm

Coral Reefs and Global Change, 1998. "Coral Reefs and Global Change: Adaptation, Acclimation or Extinction?" Initial Report of a Symposium and Workshop, Boston, January 3-11, 1998. http://coral.aoml.noaa.gov/themes/coral_cg.html

Langdon, Christopher. 2000 (in press). Global Biogeochemical Cycles.

UNEP. 2001. World Atlas of Coral Reefs. Available from University of California Press, Tel +1 510 642-4243, website: http://coral.aoml.noaa.gov/themes/coral_cg.html.

Wilkinson, Clive (ed.). 2000. Status of Coral Reefs of the World: 2000. Australian Institute of Marine Science, Townsville, Australia. Web version: http://www.reefbase.org/Summaries/GCRMN2000.htm

 

 

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