Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Airborne radar surveys and data-based models indicate West Antarctic Ice Sheet collapse is underway

13.05.2014

Discovery is latest outcome of NSF-funded International Polar Year Research

National Science Foundation- (NSF) funded researchers at the University of Washington have concluded that Antarctica's fast-moving Thwaites Glacier will likely disappear in a matter of centuries, potentially raising sea level by more than a half-a-meter (two feet).


A high-resolution map of the Thwaites Glacier's thinning ice shelf. The glacier now appears to be in the early stages of collapse, with full collapse potentially occurring within a few centuries.

Credit: David Shean / University of Washington

Data gathered by NSF-funded airborne radar, detailed topography maps and computer modeling were used to make the determination.

The glacier acts as an ice dam, stabilizing and regulating movement toward the sea of the massive West Antarctic Ice Sheet. The ice sheet contains enough ice to cause another 3 to 4 meters (10 to 13 feet) of global sea level rise.

"There's been a lot of speculation about the stability of marine ice sheets, and many scientists suspected that this kind of behavior is under way," said Ian Joughin, a glaciologist at the university's Applied Physics Laboratory (APL) and the first author on the paper. " This study provides a more quantitative idea of the rates at which the [ice sheet] collapse could take place."

The paper's co-authors are Benjamin Smith, a physicist at APL, and Brooke Medley, a former University of Washington doctoral student, now at NASA's Goddard Space Flight Center.

While the word "collapse" implies a sudden change, the fastest scenario based on the data, the researchers said, is 200 years, and the longest is more than 1,000 years.

The findings are published in the May 16 edition of the journal Science.

The new discovery is among a series of significant findings that derive from research funded by NSF during the International Polar Year (IPY) 2007-2009, during which scientists from more than 60 nations focused their efforts on research in the Arctic and Antarctic. NSF was the lead U.S. agency for the IPY

The research was funded by two NSF grants: one awarded to the Center for the Remote Sensing of Ice Sheets (CReSIS) at the University of Kansas; the other, a collaborative IPY grant, Constraining the Mass-Balance Deficit of the Amundsen Coast's Glaciers, to Joughin and his colleagues.

NASA also supported the research through grant NNX09AE47G.

The new study used airborne radar, developed by CReSIS to peer down through the thick ice and map the topography of the underlying bedrock. The shape of the underlying bedrock controls the ice sheet's long-term stability. The mapping was done as part of NASA's Operation IceBridge, a series of overflights of the ice by a P-3 research aircraft, and included other instruments to measure the height of the ice sheet's rapidly thinning surface. In some places Thwaites Glacier has been losing tens of feet, or several meters, of elevation per year.

While the timescales for a collapse of the ice sheet are in question, such a collapse may be inevitable, the researchers said.

"Previously, when we saw thinning we didn't necessarily know whether the glacier could slow down later, spontaneously or through some feedback," Joughin said. "In our model simulations it looks like all the feedbacks tend to point toward it actually accelerating over time; there's no real stabilizing mechanism we can see."

Earlier warnings of collapse had been based on a simplified model of ice sitting in an inward-sloping basin. The topography around Antarctica, however, is complex.

The researchers combined the IceBridge and CReSIS data with their own satellite measurements of ice-surface speeds. Their computer model was able to reproduce the glacier's ice loss during the past 18 years, and they ran the model forward under different amounts of ocean-driven melting.

The place where the glacier meets land, the grounding line, now sits on a shallow ridge at a depth of about 600 meters (2,000 feet) below asea level. Results show that as the ice edge retreats into the deeper part of the bay, the ice face will become steeper and, like a towering pile of sand, the fluid glacier will become less stable and collapse out toward the sea.

"Once it really gets past this shallow part, it's going to start to lose ice very rapidly," Joughin said.

The study considered future scenarios using faster or slower melt rates depending on the amount of future warming. The fastest melt rate led to the early stages lasting 200 years, after which the rapid-stage collapse began. The slowest melt rate kept most of the ice for more than a millennium before the onset of rapid collapse. The most likely scenarios may be between 200 and 500 years, Joughin said.

"All of our simulations show it will retreat at less than a millimeter of sea level rise per year for a couple of hundred years, and then, boom, it just starts to really go," Joughin said.

Researchers did not model the more chaotic rapid collapse, but the remaining ice is expected to disappear within a few decades.

-NSF-

Media Contacts Peter West, NSF, (703) 292-7530, pwest@nsf.gov Hannah Hickey, University of Washington, (206) 543.2580, hickeyh@uw.edu

Program Contacts Julie M. Palais, NSF, (703) 292-8033, jpalais@nsf.gov

Principal Investigators Ian Joughin, University of Washington, (206) 221-3177, ian@apl.washington.edu

The National Science Foundation (NSF) is an independent federal agency that supports fundamental research and education across all fields of science and engineering. In fiscal year (FY) 2014, its budget is $7.2 billion. NSF funds reach all 50 states through grants to nearly 2,000 colleges, universities and other institutions. Each year, NSF receives about 50,000 competitive requests for funding, and makes about 11,500 new funding awards. NSF also awards about $593 million in professional and service contracts yearly.

Peter West | Eurek Alert!
Further information:
http://nsf.gov/news/news_summ.jsp?cntn_id=131369&org=NSF&from=news

Further reports about: Antarctic Arctic Glacier IPY NSF Thwaites Glacier area grants

More articles from Earth Sciences:

nachricht Early organic carbon got deep burial in mantle
25.04.2017 | Rice University

nachricht New atlas provides highest-resolution imagery of the Polar Regions seafloor
25.04.2017 | British Antarctic Survey

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

Early organic carbon got deep burial in mantle

25.04.2017 | Earth Sciences

A room with a view - or how cultural differences matter in room size perception

25.04.2017 | Life Sciences

Warm winds: New insight into what weakens Antarctic ice shelves

25.04.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>