A commenter (thanks, elfish) pointed out the latest episode of Nova on PBS is about ocean acidification. I don't watch TV, or even own a TV, but you can watch all episodes of Nova on line. You can see this particular episode, Lethal Seas, here.
Ocean acidification is caused when the oceans absorb CO2, creating carbonic acid. Contrary to arguments made by deniers, no one is saying the oceans are turning into an acid. That is not what acidification means. The oceans are base and will remain base, but adding CO2 to them will reduce the level of baseness and make them more acidic. A pH of 7 is neutral (plain water) and is neither acid nor base. A pH higher than 7 is base and a pH lower than 7 is acidic. The oceans have averaged about pH 8.2 for the last 300 million years. In the last fifty years they have dropped to an average of about 8.1. Still base, but more acidic than before. That is a truly dramatic change. By becoming more acidic, the chemistry of the oceans has been changed and the consequences are extreme and widespread.
This episode of Nova explores the chemistry and effects of ocean acidification. It is extremely well done, as is the norm for Nova episodes, and explains the issue very clearly. They also explain the cause and solution very clearly. This problem is being caused by manmade emissions of CO2 and the only way it can be addressed is to reduce our CO2 emissions.
If you are interested in learning more about this issue, I highly recommend this episode as a good starting point. Even if you already know (or think you know) a lot about the subject, I still highly recommend this episode.