The expected continued drop in the pH of seawater and the possible doubling of ocean acidity measured by hydrogen ion concentration by the end of the century will not directly harm humans or marine equipment, but it will affect us indirectly in a variety of ways.
Rising ocean acidity will affect the economy. The United States is the third largest seafood consumer in the world. Increasing acidity in the oceans may harm coastal fisheries and mariculture, or ocean farming. Some people’s livelihoods depend on harvesting shellfish, such as crabs and oysters. However, as ocean acidity increases, the process of calcification — the production of shells and plates by animals for protection — will become more and more difficult, leaving these marine animals vulnerable to predators and other environmental risks.
Marine plankton, a vital food source for many marine species, could also see changes in their populations, which could have serious consequences on the entire marine food web.
More acidic oceans may also have an impact on tourism. Coral reefs, like shellfish, need calcium carbonate to produce their skeletons, but with decreasing pH levels in the water, scientists worry that coral reefs may die off, potentially diminishing the beauty and attraction of such tourist destinations. Snorkeling and scuba diving are both popular and highly lucrative tourist activities that might see their value reduced as coral reef diversity begins to disappear.
Marine organisms and their ecosystems will be most affected by rising ocean acidity, however everyone will feel the long-term effects unless we cut carbon dioxide emissions drastically.
--Andrew Dickson, marine chemist, Marine Physical Laboratory