The oceans currently absorb approximately half of human carbon dioxide (CO2) emissions from, for example, the burning of fossil fuels. Climate change would be far worse if it were not for the oceans but this comes with a cost.
When CO2 dissolves in seawater it forms carbonic acid and as more CO2 is taken up by the ocean's surface, the ocean pH decreases. This decrease in pH is known as 'ocean acidification'. It is the little known consequence of living in a high CO2 world and was dubbed the “evil twin of climate change” at the 2009 United Nations Climate Change Conference (COP15).
Ocean pH has decreased by about 30% (~ 0.1 pH unit) since the pre-industrial mid 18th Century. If we continue emitting CO2 at the same rate, ocean acidity is predicted to increase by about 150% by 2100. A rate of change that has not been experienced for at least 400,000 years. The impact of such a large change in basic ocean chemistry on ocean life, especially for those organisms that require calcium carbonate to build shells or skeletons, is unknown.
Ocean acidification is a relatively new field of research with most of the studies occuring over the last decade. While it is gaining some attention among policy makers, international leaders and the media, scientists find that there is still a lack of understanding.
The projects involved in the UKOA programme should enable some of the gaps in our current knowledge to be filled.