Not only can the scientists measure that the capacity of oceans to absorb the carbon dioxide emitted through human activities is declining.
Now New Scientist reports that they have also found that life in the oceans will be affected by the more acid oceans and this in turn will reduce the amounts of clouds, thereby contributing to global warming:
WHAT goes around comes around. Our greenhouse gas emissions don’t just warm the planet, they also acidify the oceans. Now it turns out that the change in ocean chemistry they cause will feed back into the climate, further driving up temperatures.
Ocean acidification poses a threat to many marine organisms such as corals – the shells of some marine snails are already dissolving. Until now it seemed like this was strictly a problem for marine organisms and the people who depend on them: ‘climate scientists consider the carbon dioxide that is absorbed by the ocean to be stored and unable to affect the climate.
But research now suggests that the acidification it causes will rebound on the entire planet, by acting on tiny marine plants called phytoplankton. These produce a chemical called dimethyl sulphide (DMS) that drifts up into the air and reflects sunlight back into space, cooling the planet. DMS also makes clouds brighter, with the same effect.
Read here more about how oceans are linked to greenhouse gasses:
About half of the carbon our human societies emit to the atmosphere are taken up by the oceans. A scary thing is that scientists have found that a quite tiny sea (on a planetary scale) is responsible for a large part of this absorption. The North Sea between England and Scandinavia accounts for nearly one fourth of all the carbon emitted by human activities since industrialization. The North Sea functions like our kidneys and are especially well suited for taking up carbon, which then enters the North Atlantic Ocean where it is stored or circulated to the other oceans.
The scary thing is that we do not know for how long this will continue. Scientists can measure that the rate of absorption is decreasing, and no one can say how the coming changes in global currents will affect the absorption. This might be another example of a tipping point. The higher temperatures influence the global ocean currents. This then reduces the amount of carbon that our oceans can absorb, and the temperature increases as a result.
Another factor is that carbon has other roles than being part of a greenhouse gas. When more carbon is absorbed in the oceans, they turn more acidic. The more acidic the oceans become the less CO2 they are able to absorb. But this is not all. When oceans become more acidic, living conditions for many organisms will deteriorate. This is for example the case for corals and many smaller free swimming organisms that make shells of limestone. Limestone dissolves in acids. This not only means less living organisms but also less carbon absorbed, since huge amounts of carbon are found in the limestone deposits of corals and shells.
So, many reasons for researchers to get to understand more about how our oceans function and for us all to decide how we must ensure healthy and functioning oceans.