I recently had the opportunity to chat to a local radio host on the impacts of rising CO2 levels. I was surprised to find out that, in fact, very few people are aware of how important the world's oceans are in absorbing carbon dioxide, and what the affect of rising CO2 levels in the atmosphere will have on ocean acidity, and the consequences of this. In the long term, oceans may absorb up to 85% of the anthropogenic CO2 emissions. But with all this absorbing of CO2, the oceans are becoming more acidic. It might seem like a small change in pH, but the drop of 0.1 in pH from pre-industrial to present, over only a few decades, would be similar to a natural shift in ocean pH of 5000 to 10000 years. So for ocean life which has adapted over thousands of years to a particular pH, it's a lot to deal with.
Ocean acidification not only affects marine life, but the acidification of the ocean means that the ocean can absorb less CO2. Which has a negative feedback on climate change - the rates of CO2 in the atmosphere may increase faster than predicted because the ability of the ocean to act as a sink for CO2 is diminishing. In addition to the ocean becoming more acidic, the average ocean temperature is also rising, and this further diminishes the oceans ability to absorb CO2
The affect of rising CO2 levels on the ocean is rather complicated and multifaceted. There's a whole load of ocean chemistry going on there, not just one simple straight forward equation.
To read more see this Scientific American article or see this short video:
And here's a second video from New Zealand's NIWA which I think tells the story a little better: