I remember in basic chemistry classes that carbon dioxide and water form carbonic acid, a weak acid with a pH of less than 7.
Your Viewpoint [Sustainability still hit with audiences, March 30, Page 6] said that [ocean] pH levels have increased in the last 30 years, which would imply that ocean water would become more basic, not more acidic.
Carbonic acid is extremely unstable in the range of temperatures we experience on earth, always reverting back to water and carbon dioxide. This is basic science.
An increase in acidity due to emissions of carbon dioxide and consequent adsorption into the ocean cannot be supported. Yet [the film] A Sea Change tells us otherwise without any supporting documentation.