The concept of ocean acidification is a recent phenomenon that has resulted in an explosion of journal articles, media reports and alarmist publications from environmental organizations.
Many papers on ocean acidification, said to be caused by rising man-made CO2 levels in the atmosphere, predict that it will result in the mass extinction of marine species that employ calcification, including corals, shellfish and many species of plankton, and that this, in turn, will result in the extinction of many other marine species.
Assumptions about pre-industrial ocean pH beginning around 1750 and laboratory studies that cannot adequately emulate natural oceanic conditions are the basis for the predictions of the future pH of the oceans.
Marine species that calcify have survived through millions of years during which CO2 was at much higher levels in the atmosphere.
All species are capable of adapting to changes in their environments. Over the long term, genetic evolution has made it possible for all species extant today, and their ancestors, to survive radical changes through the millennia. In the short term, phenotypic plasticity and transgenerational plasticity allow species to adapt to environmental change in relatively rapid fashion.
Seawater has a very large buffering capacity that prevents large shifts in pH when weak acids such as carbonic acid or weak bases are added to it
All species, including marine calcifying species, are capable of controlling their internal chemistry in a wide range of external conditions.
If the forecasts of continued global warming are borne out, the oceans will also become warmer and will tend to outgas CO2, offsetting to some extent the small increased partial pressure that might otherwise occur.
An analysis of research on the effect of lower pH shows a net beneficial impact on the calcification, metabolism, growth, fertility and survival of calcifying marine species when pH is lowered up to 0.3 units, which is beyond what is considered a plausible reduction during this century.
There is no evidence to support the claim that most calcifying marine species will become extinct owing to higher levels of CO2 in the atmosphere and lower pH in the oceans.