Ocean carbonate saturation, 1861-2100. Animated dataset on an Earth map showing the global changes in the saturation state of aragonite, a form of calcium carbonate, in the world's oceans from 1861 to 2100. Higher levels of saturation are blue, with saturation decreasing through yellow and orange to very low levels (red). More than a quarter of the carbon dioxide released into the atmosphere is absorbed by the oceans, where it reacts with water to form carbonic acid. This reaction lowers the concentration of carbonate ions, which are used by many marine organisms, such as coral, to form shells. As carbon dioxide levels rise and more is absorbed by the oceans, those organisms that need carbonate to make their shells will find it harder to survive. This computer model is based on past records and predictions for future levels (CMIP5, 2010-14) from the Intergovernmental Panel on Climate Change. |