Facts are funny things-The latest scare is the possible effect of extra CO2 on the world’s oceans, because more CO2 lowers the pH of seawater. While it is claimed that this makes the water more acidic, this is misleading. Since seawater has a pH around 8.1, it will take an awful lot of CO2 it to even make the water neutral (pH=7), let alone acidic (pH less than 7).
In fact, ocean acidification is a scientific impossibility. Henry's Law mandates that warming oceans will outgas CO2 to the atmosphere (as the UN's own documents predict it will), making the oceans less acid. Also, more CO2 would increase calcification rates. No comprehensive, reliable measurement of worldwide oceanic acid/base balance has ever been carried out: therefore, there is no observational basis for the computer models' guess that acidification of 0.1 pH units has occurred in recent decades
CO2 in the atmosphere has increased from 278 ppm in pre-industrial times to 390 ppm today. During this time, the amount of CO2 dissolved in the ocean has risen by more than 30%[iii], decreasing the pH of the ocean by 0.11 units. As with CO2 and global warming, there is some lag between cause and effect. That means that, even if all carbon emissions stopped today, we are committed to a further drop of up to 0.1 units.
CO2 dissolves in water to form carbonic acid.(It is worth noting that carbonic acid is what eats out limestone caves from our mountains.) In the oceans, carbonic acid releases hydrogen ions (H+), reducing pH, and bicarbonate ions (HCO3-).