Oceans are the earth’s largest sinks for carbon dioxide (CO2) emitted as a result of human activity, and the chemical properties of surface seawater change due to anthropogenic CO2 uptake. Ocean acidification, which stems from reduced seawater pH (hydrogen ion exponent), is a particular issue of concern because it accelerates global warming by reducing the capacity of oceans to take in CO2 from the atmosphere and affects marine ecosystems by disturbing plankton growth.
According to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC, 2007), it is estimated that average global surface seawater pH has decreased by 0.1 due to oceanic uptake of atmospheric CO2 emitted as a result of human activity since pre-industrial times (1750). Moreover, the outcomes of numerical model experiments based on future CO2 emission estimates indicate that surface seawater pH will further decease by 0.14 - 0.35 in the 21st century. >> More