Antarctic sea water shows ‘no sign’ of warming

Watts Up With That?
Tuesday , January 12th, 2010

From the Australian:
SEA water under an East Antarctic ice shelf showed no sign of higher
temperatures despite fears of a thaw linked to global warming that
could bring higher world ocean levels, first tests showed yesterday.

The drilling rig that was used – ironically it uses hot water to
drill! Keith Makinson and Keith Nicholls from British Antarctic Survey
hot water drilling the Filchner Ronne Ice-Shelf in a previous
expedition. 

Sensors lowered through three holes drilled in the Fimbul Ice Shelf
showed the sea water is still around freezing and not at higher
temperatures widely blamed for the break-up of 10 shelves on the
Antarctic Peninsula, the most northerly part of the frozen continent in
West Antarctica.

Click for larger map 

“The water under the ice shelf is very close to the freezing
point,” Ole Anders Noest of the Norwegian Polar Institute wrote
after drilling through the Fimbul, which is between 250m and 400m thick.

“This situation seems to be stable, suggesting that the
melting under the ice shelf does not increase,” he wrote of the
first drilling cores. 

The findings, a rare bit of good news after worrying signs in recent
years of polar warming, adds a small bit to a puzzle about how
Antarctica is responding to climate change, blamed largely on human use
of fossil fuels.

Antarctica holds enough water to raise world sea levels by 57m if it
ever all melted, so even tiny changes are a risk for low-lying coasts
or cities from Beijing to New York.

Ole Anders Nøst attaches temperature sensors to the cable as it
is lowered into the borehole. Image: Lars Henrik Smedsrud 

The Institute said the water under the Fimbul was about -2.05C.
Salty water freezes at a slightly lower temperature than fresh water.

And it was slightly icier than estimates in a regional model for
Antarctica, head of the Norwegian Polar Institute’s Center for
Ice, Climate and Ecosystems, Nalan Koc, said.

“The important thing is that we are now in a position to monitor the water beneath the ice shelf.

“If there is a warming in future we can tell.”

She said data collected could go into a new report by the UN’s Intergovernmental Panel on Climate Change, due in 2013-14.

The last IPCC report, in 2007, did not include computer models for sea temperature around the Fimbul Ice Shelf.

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From the expedition web site: http://fimbul.npolar.no/en/news/current/Nye_data.html

We observed a roughly 50 meter deep layer of water with temperatures
very close to the freezing point, about -2.05 degrees, just beneath the
ice shelf. The highest observed temperature was about -1.83 degrees
close to the bottom. The temperatures are very similar to temperature
data collected by elephant seals in 2008 and by British Antarctic
Survey using an autosub below the ice shelf in 2005.

We collected three profiles from the underside of the ice to the
seabed at 653 meters below sealevel. No trace of the relatively warm
deep water that upwells over the continental slope was found. It will
be exciting to see if this is the situation all year round, says Ole
Anders Nøst.

For more on how the drilling was done, see this PDF of the method and equipment here

More on the project here