An international team of researchers from the University of East Anglia, the British Antarctic Survey (BAS) and the Max-Planck Institute for Biogeochemistry have found that that the Southern Ocean's ability to absorb carbon dioxide has reached a saturation point.
During their four-year study, researchers found that an increase in winds over the Southern Ocean, caused by greenhouse gases and ozone depletion, has led to a release of stored CO2 into the atmosphere and is preventing further absorption of the greenhouse gas.
"This is the first time that we've been able to say that climate change itself is responsible for the saturation of the Southern Ocean sink. This is serious. All climate models predict that this kind of 'feedback' will continue and intensify during this century. The Earth's carbon sinks - of which the Southern Ocean accounts for 15 percent - absorb about half of all human carbon emissions. With the Southern Ocean reaching its saturation point, more CO2 will stay in our atmosphere," said lead author of the study, Dr Corinne Le Quťrť of UEA and BAS.
According to the study, the stabilisation of atmospheric CO2 is even more difficult to achieve than previously thought.
Additionally, acidification in the Southern Ocean is likely to reach dangerous levels earlier than the projected date of 2050, they said.
Professor Chris Rapley, Director of British Antarctic Survey said: "Since the beginning of the industrial revolution, the world's oceans have absorbed about a quarter of the 500 gigatons of carbon emitted into the atmosphere by humans. The possibility that in a warmer world the Southern Ocean - the strongest ocean sink - is weakening is a cause for concern".
The findings appear in this week's edition of the journal Science.