This is dire news. The journal science reports that rising Ocean Acidification as more CO2 is absorbed by the oceans is creating a feedback loop by reducing Phytoplankton, causing less dimethylsulphide (DMS) to be released. DMS in the atmosphere in important in cloud formation, fewer fewer clouds reflecting less sunlight back to space, resulting in accelerating warming.
Rising ocean acidity will exacerbate global warming
By Eliot Barford
The slow and inexorable increase in the oceans’ acidity as they soak up carbon dioxide from the atmosphere could itself have an effect on climate and amplify global warming, according to a new study. Acidification would lead certain marine organisms to emit less of the sulphur compounds that help to seed the formation of clouds and so keep the planet cool.
Atmospheric sulphur, most of which comes from the sea, is a check against global warming. Phytoplankton — photosynthetic microbes that drift in sunlit water — produces a compound called dimethylsulphide (DMS). Some of this enters the atmosphere and reacts to make sulphuric acid, which clumps into aerosols, or microscopic airborne particles. Aerosols seed the formation of clouds, which help cool the Earth by reflecting sunlight.
Back in the 1980s researcher James Lovelock hypothesized that that rising CO2 would increase DMS emissions putting a brake on accelerated warming. But now researchers have discovered the opposite it true with increased CO2 is lowering DMS emissions instead as the oceans grow increasingly acidic as they absorb more C2
More recently, thinking has shifted towards predicting a feedback in the opposite direction, because of acidification. As more CO2 enters the atmosphere, some dissolves in seawater, forming carbonic acid. This is decreasing the pH of the oceans, which is already down by 0.1 pH units on pre-industrial times, and could be down by another 0.5 in some places by 2100.
And studies using 'mesocosms' — enclosed volumes of seawater — show that seawater with a lower pH produces less DMS2. On a global scale, a fall in DMS emissions due to acidification could have a major effect on climate, creating a positive-feedback loop and enhancing warming.
The Oceans are a massive part of our planet's ecology, and not only are they in trouble but as science learns more about all the feedback loops involved we keep finding out that the problem is far more serious that we had previously thought. The baseline keeps getting worse with the more we learn.
Sky meets the Sea