The Impact of Climate Change on Coral Reef Ecosystems

Human activities such as the burning of fossil fuels, deforestation and changing land use have dramatically altered the atmospheric concentration of greenhouse gases such as carbon dioxide and methane. These changes have resulted in global warming and ocean acidification, both of which pose serious threats to coral reef ecosystems through increased thermal stress and ocean acidity as well as declining carbonate ion concentrations. Observed impacts on coral reefs include increased mass coral bleaching, declining calcification rates, and a range of other changes to subtle yet fundamentally important physiological and ecological processes. There is little evidence that reef-building corals and other organisms will be able to adapt to these changes leading to the conclusion reef ecosystems will become rare globally by the middle of the current century. Constraining the growth of carbon dioxide in the atmosphere as well as reducing local stresses such as overfishing and declining water quality, however, holds considerable hope for avoiding this gloomy future for coral reefs. Given the importance of coral reefs to the livelihoods of millions of people, actions such as these must be pursued as a matter of extreme urgency.