After attending the talk "Ocean Acidification - The Other CO2 Problem" here at COP19 in Warsaw, it is quite clear that there is another significant issue concerning climate change. About one-quarter of the human-made CO2 emissions have been absorbed by oceans creating yet another environmental problem of global concern. We are changing seawater chemistry through a type of carbon sequestration. This creates a potential environmental disaster in the ocean and delays the inevitable temperature rise associated with our CO2 emissions. Starting with the impact from the ocean's perspective -- CO2 is absorbed and dissolved in water which forms carbonic acid.
Carbonic acid releases the acidic proton, increasing acidity and decreasing the amount of carbonate ion, tipping the balance of the "saturation state" of calcium carbonate -- the building block for shells. These changes in the ocean water chemistry spell disaster not just for shellfish (molluscs) but for the entire marine ecosystem. Acidification threatens yields of seafood for communities that rely on the oceans for their economy and to feed their own people. The resulting lower pH is also dissolving coral reefs which provide a habitat for close to 25 percent of worldwide marine species
A few quick facts concerning acidification from the Ocean Acidification International Coordination Center (OA-ICC);
• The acid level in the ocean is changing at a pace that is a hundred times faster than any time during the last 20million years
• There has been an increase of more than 30 percent acidity since the beginning of the Industrial Revolution
• If CO2 emissions continue at the current rate, the acidity rise could reach 150 percent by the end of the century
• At the current rate of acidification, the polar oceans could actually begin to dissolve the shells of living organisms within decades
• Many coral reefs could disappear by the middle of this century
• Three billion people rely on the oceans for their animal protein intake, and acidification threatens their food security
There is hope though. The IPCC started to recognize ocean acidification in 2007, and RIO +20 called for significant initiatives to mitigate the effect. In addition, GOA-ON, the Global Ocean Acidification Observing Network is trying to get a better handle on the extent of acidification worldwide. In Mexico in 2010 at COP16, the Cancun Agreements barely mentioned Ocean Acidification and identified it as a "slow moving event". We now recognize that the atmosphere and the ocean are inexorably linked.