Ocean acidification

Anthropogenic CO2 emissions arise mainly from fossil-fuel combustion, land-use practices, and concrete production during and since the industrial revolution. These emissions first enter the atmosphere, but a large proportion of them are then absorbed into the ocean by physical and biological processes that are normal parts of the natural carbon cycle. The result is more CO2 dissolved in the world’s oceans. The ocean is a weakly-alkaline solution (with a pH of ~8.1), but this extra CO2 changes the carbonate chemistry of the surface ocean, driving ocean pH lower. The term ‘ocean acidification’ refers to the fact that the CO2 forms a weak acid (carbonic acid) in water, making the ocean more acidic