How Carbon Dioxide Is Making The Ocean Acidic

Harry - I'm also interested in carbon. I'm a chemist and work on what the climate was like in the past on different time scales. We can learn about what might happen in the future by understanding the natural variability in the past.

Chris - The oceans cover a massive amount of the earth's surface and apparently account for most of the carbon dioxide that is on the planet.

Harry - Not all of it. Some of it obviously stays in the atmosphere while a fair bit of it is on land. It is true that the oceans are a huge reservoir and about half of the carbon from fossil fuels ends up in the sea.

Chris - Carbon dioxide gives rise to an acid when you dissolve it in water. What are the consequences of essentially all this acid being dumped in the ocean?

Harry - This is the thing that people are beginning to think about. It makes the sea water slightly more acidic than normal and it is going to be a real problem. There is evidence from experiments that many of the marine organisms don't like it because their shells are calcified. This is when their shells are made from calcium carbonate, which is a mineral like a bone. Some of these organisms are going to be more at risk, especially corals, as the form of this mineral is more soluble than other organisms. This slightly acidic seawater will stop them calcifying. There is evidence in corals such as bleaching because they are moving to areas that are better for them to live in. We have to do something about it.