Ocean Acidification
by The Ocean Portal Team; Reviewed by Jennifer Bennett (NOAA)

Even though the ocean is immense, enough carbon dioxide can have a major impact. In the past 200 years alone, ocean water has become 30 percent more acidic

<-- This is a massive blunder by NOAA. It shatters my confidence in "climate scientists".

I think she meant to say that there is 30% more CO2 in the ocean than pre-industrial times.

The statement "30% more acidic" is wrong for 2 reasons:
1) When CO2 (carbon dioxide) dissolves in water only 0.3% of it becomes carbonic acid according to the equation:

CO2(aq)  +  H2O(aq)  <=>  H2CO3(aq)

Most of the CO2 simply dissolves in water without making carbonic acid.

2) Carbonic acid is a weak acid with a Ka = 4.2E-04. Meaning less than 1% of that dissociates according to the formula:

H2CO3(aq) + H2O(aq) <=> H3O+(aq) + HCO3-(aq)