Rice U. Antarctic expert available to discuss ice-shelf breaks

David Ruth
713-348-6327
david@rice.edu

Jade Boyd
713-348-6778
jadeboyd@rice.edu

Rice U. Antarctic expert available to discuss ice-shelf breaks

John Anderson available to discuss Larsen C, Pine Island rifts

HOUSTON — (Jan. 9, 2017) — Rice University oceanographer John Anderson, a veteran of 24 research expeditions to the Antarctic, is available to discuss the potential causes and impacts of dramatic rifts that have developed in two Antarctic ice shelves, the Larsen C ice shelf on the Antarctic Peninsula and the Pine Island ice shelf in western Antarctica’s Amundsen Sea.

A massive rift in the Antarctic Peninsula’s Larsen C ice shelf was photographed Nov. 10 on a research flight by NASA’s IceBridge mission. (Photo by NASA/John Sonntag)

The Larsen C fracture, which is about 70 miles long and cuts through the ice shelf, grew by an estimated 11 miles last month and could produce an iceberg approximately the size of Delaware if it continues to break through to the Weddell Sea. Though smaller, the Pine Island rift, which scientists have been monitoring since 2015, is located in a more critical area and could have more serious consequences, Anderson said.

Anderson, Rice’s W. Maurice Ewing Professor of Oceanography and professor of Earth science, can discuss the waxing and waning of marine ice sheets throughout history, how climate change and ocean warming in the Antarctic are weakening the continent’s ice sheets, and the potential impact that the breakup of ice sheets could have on sea level.

“Ice shelves are floating structures that act like corks to keep Antarctic glaciers bottled up on land,” Anderson said. “Just as melting ice cubes don’t increase the level of water in a glass, melting ice shelves do not increase sea level. However, the breakup of ice shelves does allow glaciers and ice streams to flow much more rapidly, and these do contribute to sea-level rise.”

John Anderson

For instance, glaciers that were once behind the Larsen B ice shelf today flow as much as 10 times faster into the Weddell Sea than they did prior to the breakup of that ice shelf in 2002.

The rift in the Pine Island ice shelf was discovered by scientists who were measuring a 2013 break in the shelf that produced a Chicago-sized iceberg. While berg-forming rifts are common in all ice shelves, the breaks usually form at the sides of the shelves. Both the 2013 and 2015 breaks began in the middle of the Pine Island ice shelf.

“The most likely explanation is that the shelf is being eaten away from below by warmer water from the nearby ocean,” Anderson said. “There’s ample evidence that ice sheets have collapsed in exactly this way during warming periods in Earth’s distant past.”

Because the Pine Island glacier, which stands behind the Pine Island ice shelf, is one of the five-largest ice streams in Antarctica, Anderson said a breakup of the Pine Island ice shelf would have more far-reaching consequences than a Larsen C breakup.

“The Pine Island glacier and its nearby twin, the Thwaites Glacier, are two of the primary outlets for the Western Antarctic Ice Sheet,” Anderson said. “That ice is as much as 2,000 meters thick, but it sits on ground that is below sea level and is therefore believed to be particularly vulnerable to runaway melting, should the seaward ice shelves break apart.”

To arrange an interview with Anderson, contact David Ruth at david@rice.edu or 713-348-6327 or Jade Boyd at jadeboyd@rice.edu or 713-348-6778.

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IMAGE available for download:

https://www.nasa.gov/image-feature/rift-in-antarcticas-larsen-c-ice-shelf
CAPTION: A massive rift in the Antarctic Peninsula’s Larsen C ice shelf was photographed Nov. 10 on a research flight by NASA’s IceBridge mission. (Photo by NASA/John Sonntag)

http://news.rice.edu/files/2016/02/0217_ROSS-And4-lg-122l54i.jpg
CAPTION: John Anderson (Photo by Jeff Fitlow/Rice University)

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