"The present rate of CO2 emissions will produce an atmospheric concentration in 100 years not experienced during the past 20 million years and water temperatures above those of the past interglacial 130,000 years before present. Human influences on water temperatures, seawater chemistry (toxic substances, nutrients and aragonite saturation), the spread of diseases, removal of species and food web alterations are presently changing reef ecology. A significant ecological reorganization is underway and changes include a reduction in calcifying and zooxanthellae-hosting organisms, their obligate symbionts, and species at higher trophic levels, with an increase in generalist species of low trophic level that are adapted to variable environments. Late-successional fleshy brown algae of low net productivity or non-commercial invertebrates such as sea urchins, starfish and coral-eating snails will dominate many reefs. These changes will be associated with a loss of both net benthic and fisheries production and inorganic carbonate deposition; this will reduce reef complexity, species richness, reef growth and increase shoreline erosion." So begins a pessimistic assessment of the future of coral reefs in the journal Environmental Conservation.

The review analyses trends affecting coral reefs in response to such pressures as climatic oscillations and disturbances, oceanographic and environmental changes, consumption of fish and invertebrates, and diseases. It argues that coral reefs are "currently undergoing a global-scale change in their ecology associated with a number of synergistic disturbances." The trajectory of this change, it continues, is "from localized small-scale disturbances such as fishing, river discharge, and pollution towards regional and global-level disturbances associated with warm water, diseases and changes in seawater chemistry." As a result of such changes, "losses in coral species at the local level and possible extinction in regions with small shelf size are likely to continue."

Furthermore, the management of coral reefs "is no longer an environmental issue restricted to tropical countries and their donors; global climate change and globalization of trade have made their management a global concern and responsibility.

Management is also no longer a simple issue of managing local pollution and maintaining sustainability of fisheries, but must also consider the global context when making local decisions. Management efforts are, therefore, needed from the local to the global levels."

On a global level, "efforts to reduce greenhouse gases now will have little effect on coral reefs in the next 25 years, but there is a need to support ongoing efforts to reduce greenhouse gases in order to reduce climate change effects in the coming centuries. Restrictions on the global trade of reef resources such as sharks, ornamentals and the live-fish trade are, however, one area where immediate action at the global level can reduce further degradation. Management of watersheds and water quality is an important issue at the regional level, where greater effort to reduce the influx of inorganic and organic nutrients and sediments should promote reef resistance to and recovery after disturbances."

At the regional to global level, the review urges the need to identify and manage species which may be particularly vulnerable to extinction, and to identify specific reef ecosystems and species that will require special protection "in order to persist through the coming age of global warming and the intense resource use driven by the poverty of tropical countries."

Finally, on a local to regional level, "there is a need to renew efforts for sustainable fisheries management through restrictions on space, species, size, gear and effort." Among the most essential elements in this regard is the need to "alleviate poverty such that fishing is not one of a very few major economic options for tropical people. This requires economic planning and implementation and improved attempts to realistically balance populations, resources and economic growth. The responsibility for balancing ecological and economic production and the control of carbon, toxic and nutrient wastes from both tropical and temperate nations are needed to provide an improved future for coral reefs and their economic services."

December 2003