Global ocean flows to be dramatically slowed by rising Antarctic ice melt

The effect of meltwater on global ocean circulation has not yet been included in the complex models used by the IPCC to describe future climate change scenarios, but it is going to be considerable, England said.

Ocean overturning allows nutrients to rise up from the bottom, with the Southern Ocean supporting about three-quarters of global phytoplankton production, the base of the food chain, said a second study co-author, Steve Rintoul.

"If we slow the sinking near Antarctica, we slow down the whole circulation and so we also reduce the amount of nutrients that get returned from the deep ocean back up to the surface," said Rintoul, a fellow at Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO).

The study's findings also suggest the ocean would not be able to absorb as much carbon dioxide as its upper layers become more stratified, leaving more CO2 in the atmosphere.

The study showed that warm water intrusions in the western Antarctican ice shelf would increase, but it did not look at how this might create a feedback effect and generate even more melting. "It doesn't include the disaster scenarios," said Mix. "In that sense, it's actually kind of conservative."