Oops. Southern Ocean Overturning Current Velocity Down 30% Since 1990s - Study
A major global deep ocean current has slowed down by approximately 30% since the 1990s as a result of melting Antarctic ice, which could have critical consequences for Earth’s climate patterns and sea levels, new research suggests. Known as the Southern Ocean overturning circulation, the global circulation system plays a key role in influencing the Earth’s climate, including rainfall and warming patterns. It also determines how much heat and carbon dioxide the oceans store.
Scientists warn that its slowdown could have drastic impacts, including increasing sea levels, altering weather patterns and depriving marine ecosystems of vital nutrients. “Changes in the overturning circulation are a big deal,” said the study’s co-author, Dr Steve Rintoul, an oceanographer and expert on the Southern Ocean at the Australian government’s Commonwealth Scientific and Industrial Research Organisation (CSIRO). “It’s something that is a concern because it touches on so many aspects of the Earth, including climate, sea level, and marine life.”
The finding comes months after modelling, which Rintoul was involved in, that predicted a 40% slowdown in the circulation by 2050. “The model projections of rapid change in the deep ocean circulation in response to melting of Antarctic ice might, if anything, have been conservative,” Rintoul said. “We’re seeing changes have already happened in the ocean that were not projected to happen until a few decades from now.”
EDIT
Between 1994 and 2017, there was a net slowdown in the circulation by 0.8 sverdrups per decade, the study found. One sverdrup is a flow rate equivalent to 1 million cubic metres per second. The researchers found a temporary increase in the overturning circulation between 2009 and 2017, as a result of increased sea ice formation. “That was enough to compensate for the melt from glacial melt for a few years,” Rintoul said.
EDIT
https://www.theguardian.com/science/2023/may/25/slowing-ocean-current-caused-by-melting-antarctic-ice-could-have-drastic-climate-impact-study-says
