... the Antarctic ice sheet is now losing 159 billion tonnes of ice each year – twice as much as when it was last surveyed.
... these newly measured losses from Antarctica alone are enough to raise global sea levels by 0.45 mm each year.
... the increased thinning we have detected in West Antarctica is a worrying development,' said Professor Shepherd. [emphasis mine]
New research on the impact of increasing Westerlies indicates that Antarctic Ice Sheet Melt may be even faster than 3 meters over 200 -500 years. Add a few tenths of a meter of sea level rise this century, for starters.
Sea levels may rise much faster than predicted because climate models have failed to account for the disruptive effects of stronger westerly winds, Australian-led research has found.
Recent studies of Antarctica have suggested the giant glaciers of West Antarctica may have begun an irreversible melting that will raise sea levels by as much as 3 metres over 200-500 years.
That estimate, though, may prove optimistic because models had failed to account for how strengthening westerly winds in the Southern Ocean would start to impinge coastal easterlies, upsetting a delicate balance of warm and cold waters close to the Antarctic ice sheets, said Paul Spence, an oceanographer at the University of NSW’s Climate Change Research Centre.
“It’s the first time that I looked at my science and thought, 'Oh my god, that is very concerning'!”, he said. “You hope it’s wrong and you hope it doesn’t happen.
The research, published in Geophysical Research Letters, found that the coastal temperature structure was more sensitive to global warming, particularly the changes to winds, than previously identified.
“The dynamic barrier between cold and warm water relaxes, and this relatively warm water just offshore floods into the ice-shelf regions, increasing the temperatures by 4 degrees under the ice shelf,” he said.
“If you look at how sensitive the coastal ocean is to these changing winds, you could put a lot more heat under these ice shelves than people have previously thought,” Dr Spence said.
The new modelling shows it doesn’t take much additional wind to the system “to really, dramatically upset" conditions, he said. “It’s a system really dramatically ripe for change.”
“This paper is a necessary first step to actually closing some the understanding gaps,” Dr van Ommen said.
While predictions of future sea-level rise were difficult to make, “adding a few tenths of a metre from ice instability this century is a significant concern”, he said. [emphasis mine]