The article explains the problem to calcium carbonate dependent ocean life thusly: Thus the ocean's concentration of carbonate ions is reduced, creating an imbalance in the reaction Ca2+ + CO32− \leftrightarrow CaCO3, and making the dissolution of formed CaCO3 structures more likely. My emphasis in bold... Is this saying that carbonate ions are reduced or the ratio is changed? Looking at the chemistry it appears that the concentration of carbonate ions will still increase but not as much as bicarbonate. This means a reduction in the relative abundance of carbonate not the actual abundance (which is still increasing). This also leads to a paradox whereby increasing CO2 will lead to an increase in Carbonate formation even with a decrease in pH. Precisely the opposite situation than has been suggested that marine life not having adequate carbonate.