How does global warming cause the oceans to become more acidic?

Question

If acidity is a function of the concentration of H+ then how does CO2 affect this?

Answer 1

When CO2 dissolves in water it forms the weak acid carbonic acid. H2CO3. As temp of air increases the surface temp of the ocean will increase and the solubility of CO2 will increase

Answer 2

I think this explanation helps explain why:

"Unlike any possible controversy over global warming, as you increase carbon dioxide in the atmosphere, you're driving carbon into the oceans and increasing the ocean's acidity -- and this is not debatable," said Joan Kleypas, an ecologist and geologist in Boulder, Colo.

The scientists noted that carbon changes the ocean's chemical nature from normally alkaline to abnormally acidic. That change, in turn, lowers the concentration of carbonate ions, which are the building blocks of the calcium carbonate that many of the most important marine organisms use to grow their shells and create the structures that form coral reefs that provide vital habitat for fish and other marine species, the scientists explained.

The pace of change from alkaline to acidic water, the report said, has increased rapidly over the past 200 years as industrial carbon dioxide in the atmosphere dumped more carbon into the world's oceans. For hundreds of thousands of years before that, the acidity of the world's oceans remained steady based on the study of ice cores, the scientists said.