The current debate on the connection between CO2 emissions and climate change has largely overlooked an independent and equally serious problem, the increasing acidity of our oceans. Last December, the respected  journal “Oceanography” published projections (see graphic below) for this rising acidity, measured by falling pH [i], through to the end of the century [ii].

CO2 in the atmosphere has increased from 278 ppm in pre-industrial times to 390 ppm today. During this time, the amount of CO2 dissolved in the ocean has   risen by more than 30%, decreasing the pH of the ocean by 0.11 units. As with CO2 and global warming, there is a lag between cause and effect. That means we are yet to see the worst of the problem. According to the Australian Antarctic Division of our Department of the Environment, “even if all carbon emissions stopped today, we are committed to a further drop of 0.1 to 0.2 pH units” [iii]. However, if CO2 is allowed to rise along a business-as-usual trajectory, they are concerned that pH will “fall by 0.5 pH units by 2100, a 320% increase in acidity”.

Read the rest of this article by Alan Marshall, including numerous helpful illustrations and references, in Skeptical Science, 17 March 2011. Article.