Featured Research

from universities, journals, and other organizations

Warm ocean currents cause majority of ice loss from Antarctica

Date:
April 25, 2012
Source:
British Antarctic Survey
Summary:
Warm ocean currents are the dominant cause of recent ice loss from Antarctica, new research shows. New techniques have been used to differentiate, for the first time, between the two known causes of melting ice shelves - warm ocean currents attacking the underside, and warm air melting from above. This finding brings scientists a step closer to providing reliable projections of future sea-level rise.

Wilkins ice sheet on the Antarctic penninsula.
Credit: Image courtesy of British Antarctic Survey

An international team of scientists led by British Antarctic Survey (BAS) has established that warm ocean currents are the dominant cause of recent ice loss from Antarctica. New techniques have been used to differentiate, for the first time, between the two known causes of melting ice shelves -- warm ocean currents attacking the underside, and warm air melting from above. This finding brings scientists a step closer to providing reliable projections of future sea-level rise.

Researchers used 4.5 million measurements made by a laser instrument mounted on NASA's ICESat satellite to map the changing thickness of almost all the floating ice shelves around Antarctica, revealing the pattern of ice-shelf melt across the continent. Of the 54 ice shelves mapped, 20 are being melted by warm ocean currents, most of which are in West Antarctica.

In every case, the inland glaciers that flow down to the coast and feed into these thinning ice shelves have accelerated, draining more ice into the sea and contributing to sea level rise.

Lead author Dr Hamish Pritchard from British Antarctic Survey, which is funded by the UK's Natural Environment Research Council (NERC), said: "In most places in Antarctica, we can't explain the ice-shelf thinning through melting of snow at the surface, so it has to be driven by warm ocean currents melting them from below.

"We've looked all around the Antarctic coast and we see a clear pattern: in all the cases where ice shelves are being melted by the ocean, the inland glaciers are speeding up. It's this glacier acceleration that's responsible for most of the increase in ice loss from the continent and this is contributing to sea-level rise.

"What's really interesting is just how sensitive these glaciers seem to be. Some ice shelves are thinning by a few metres a year and, in response, the glaciers drain billions of tons of ice into the sea. This supports the idea that ice shelves are important in slowing down the glaciers that feed them, controlling the loss of ice from the Antarctic ice sheet. It means that we can lose an awful lot of ice to the sea without ever having summers warm enough to make the snow on top of the glaciers melt -- the oceans can do all the work from below.

"But this does raise the question of why this is happening now. We think that it's linked to changes in wind patterns. Studies have shown that Antarctic winds have changed because of changes in climate, and that this has affected the strength and direction of ocean currents. As a result warm water is funneled beneath the floating ice. These studies and our new results therefore suggest that Antarctica's glaciers are responding rapidly to a changing climate."

A different picture is seen on the eastern Antarctic Peninsula (the long stretch of land pointing towards South America). Here, the ice-shelf thinning found by this study can be explained by warm summer winds directly melting the snow on the ice-shelf surfaces. Both patterns, of widespread ocean-driven melting and this summer melting on the Antarctic Peninsula, can therefore be attributed to Antarctica's changing wind patterns.

This research is part of international efforts to improve understanding of the interactions between ice and climate in order to improve the reliability of sea-level rise projections. Professor David Vaughan is the leader of ice2sea -- a major EU-funded FP7 program. He said, "This study shows very clearly why the Antarctic ice sheet is currently losing ice, which is a major advance. But the real significance is that it also shows the key to predicting how the ice sheet will change in the future is in understanding the oceans. Perhaps we should not only be looking to the skies above Antarctica, but also into the surrounding oceans."

The study was carried out by an international team from British Antarctic Survey, Utrecht University, University of California in San Diego and Earth & Space Research in Corvallis, Oregon. NASA's ICESat -- Ice, Cloud and Land Elevation Satellite -- measurements were collected during the period 2003 -- 2008 to detect changes in ice-shelf thickness through time.


Story Source:

The above story is based on materials provided by British Antarctic Survey. Note: Materials may be edited for content and length.


Journal Reference:

  1. H. D. Pritchard, S. R. M. Ligtenberg, H. A. Fricker, D. G. Vaughan, M. R. van den Broeke, L. Padman. Antarctic ice-sheet loss driven by basal melting of ice shelves. Nature, 2012; 484 (7395): 502 DOI: 10.1038/nature10968

Cite This Page:

British Antarctic Survey. "Warm ocean currents cause majority of ice loss from Antarctica." ScienceDaily. ScienceDaily, 25 April 2012. <www.sciencedaily.com/releases/2012/04/120425140353.htm>.
British Antarctic Survey. (2012, April 25). Warm ocean currents cause majority of ice loss from Antarctica. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2012/04/120425140353.htm
British Antarctic Survey. "Warm ocean currents cause majority of ice loss from Antarctica." ScienceDaily. www.sciencedaily.com/releases/2012/04/120425140353.htm (accessed July 25, 2014).

Share This




More Earth & Climate News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Goma Cheese Brings Whiff of New Hope to DRC

Goma Cheese Brings Whiff of New Hope to DRC

Reuters - Business Video Online (July 24, 2014) The eastern region of the Democratic Republic of Congo, mainly known for conflict and instability, is an unlikely place for the production of fine cheese. But a farm in the village of Masisi, in North Kivu is slowly transforming perceptions of the area. Known simply as Goma cheese, the Congolese version of Dutch gouda has gained popularity through out the region. Ciara Sutton reports. Video provided by Reuters
Powered by NewsLook.com
Bill Gates: Health, Agriculture Key to Africa's Development

Bill Gates: Health, Agriculture Key to Africa's Development

AFP (July 24, 2014) Health and agriculture development are key if African countries are to overcome poverty and grow, US software billionaire Bill Gates said Thursday, as he received an honourary degree in Ethiopia. Duration: 00:36 Video provided by AFP
Powered by NewsLook.com
Higgins Breaks Record at Mt. Washington

Higgins Breaks Record at Mt. Washington

Driving Sports (July 24, 2014) Subaru Rally Team USA drivers David Higgins and Travis Pastrana face off against a global contingent of racers at the annual Mt. Washington Hillclimb in New Hampshire. Includes exclusive in-car footage from Higgins' record attempt. Video provided by Driving Sports
Powered by NewsLook.com
Storm Kills Three, Injures 20 at Virginia Campground

Storm Kills Three, Injures 20 at Virginia Campground

Reuters - US Online Video (July 24, 2014) A likely tornado tears through an eastern Virginia campground, killing three and injuring at least 20. Linda So reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

    Health News

      Environment News

        Technology News



          Save/Print:
          Share:

          Free Subscriptions


          Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

          Get Social & Mobile


          Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

          Have Feedback?


          Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
          Mobile: iPhone Android Web
          Follow: Facebook Twitter Google+
          Subscribe: RSS Feeds Email Newsletters
          Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins