The vast Southern Ocean around Antarctica has started to soak up more greenhouse gases from the atmosphere in recent years, helping to limit climate change, after signs its uptake had stalled, a study said on Thursday.

The Southern Ocean's natural absorption of carbon roughly doubled to 1.2 billion tons in 2011 — equivalent to the European Union's annual man-made greenhouse gas emissions — from levels a decade earlier, it said.

"It's good news, for the moment" for efforts to slow man-made global warming, said Nicolas Gruber, an author of the study at Swiss university ETH Zurich.