Coral reef ecosystems and anthropogenic climate change

Coral reef ecosystems are among the most biologically diverse ecosystems on the planet. In addition to their value in terms of biodiversity, coral reefs provide food and resources for over 500 million people. Despite their importance, coral reefs are declining at a rapid rate (1–2% per year) as a result of a range of local (e.g., overexploitation of fisheries, declining water quality) and global (e.g., global warming and ocean acidification) drivers. Extensive experimental and field evidence suggests that atmospheric carbon dioxide concentrations of 450 ppm will lead to the loss of coral-dominated reef systems, with the prospect that dangerous levels of atmospheric carbon dioxide for coral reefs were exceeded in 1979 when mass coral bleaching was reported for the first time. The exact response of coral reefs remains uncertain although it is highly unlikely that coral-dominated reef systems will be present in future oceans at the current rate of warming and acidification of the world’s tropical oceans. The loss of these important coastal ecosystems will diminish the resources available to hundreds of millions of people along tropical coastlines. Understanding the impacts on people and industry is an imperative if we are to devise effective systems by which tropical coastal communities are to adapt to rapidly changing tropical coastal environments. Our current understanding of these important issues, however, is in a relatively undeveloped state and must be a priority of future research.