|As the oceans warm, they cease to absorb so much CO2 - they reach a limit. That means CO2 has to stay in the atmosphere. In other words, we have been protected by the oceans absorbing a lot of the CO2 we throw at them. The Southern Ocean (around Antarctica) has now been found to be effectively saturated. With that storage coming to an end, atmospheric CO2 is going up faster, and so will global warming. That's known as positive feedback.
Quoting an article in Science, the The Independent, UK writes:
"This is the first unequivocal detection of a carbon sink weakening because of recent climate change," said the lead author of the study, Corinne Le Quéré, of the University of East Anglia. "This is serious. Whenever the world has greatly warmed in the past, the weakening of CO2 sinks has contributed to it."
Professor Chris Rapley, director of the British Antarctic Survey, said: "Since the beginning of the Industrial Revolution the world's oceans have absorbed about a quarter of the 500 gigatons [millions of tonnes] of carbon emitted by humans. The possibility that in a warmer world the Southern Ocean is weakening is a cause for concern."
[Photo BBC News]