Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

West Antarctic Ice Sheet collapse is under way

15.05.2014

The West Antarctic Ice Sheet, which holds enough water to raise global seas by several feet, is thinning. Scientists have been warning of its collapse, based on theories, but with few firm predictions or timelines.

University of Washington researchers used detailed topography maps and computer modeling to show that the collapse appears to have already begun. The fast-moving Thwaites Glacier will likely disappear in a matter of centuries, researchers say, raising sea level by nearly 2 feet.


This is a photo of the Thwaites ice shelf taken during an October 2013 Operation IceBridge aerial survey.

Credit: James Yungel / NASA


This is a high-resolution map of Thwaites Glacier's thinning ice shelf. Warm circumpolar deep water is melting the underside of this floating shelf, leading to an ongoing speedup of Thwaites Glacier. This glacier now appears to be in the early stages of collapse, with full collapse potentially occurring within a few centuries. Collapse of this glacier would raise global sea level by several tens of centimeters, with a total rise by up to a few meters if it causes a broader collapse of the West Antarctic Ice Sheet.

Credit: David Shean / Univ. of Washington

That glacier also acts as a linchpin on the rest of the ice sheet, which contains enough ice to cause another 10 to 13 feet (3 to 4 meters) of global sea level rise. The study is published May 16 in Science.

"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 UW's Applied Physics Laboratory. "This study provides a more quantitative idea of the rates at which the collapse could take place."

... more about:
»Antarctic »Antarctica »Glacier »Physics »measurements

The good news is that while the word "collapse" implies a sudden change, the fastest scenario is 200 years, and the longest is more than 1,000 years. The bad news is that such a collapse may be inevitable.

"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 new study used airborne radar, developed at the University of Kansas with funding from the National Science Foundation, to image through the thick ice and map the topography of the underlying bedrock, whose shape controls the ice sheet's long-term stability.

The mapping was done as part of NASA's Operation IceBridge, 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.

UW researchers combined that 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 shallower ridge with a depth of about 2,000 feet (600 meters). 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.

The thinning of the ice in recent decades is most likely related to climate change, Joughin said. More emissions would lead to more melting and faster collapse, but other factors make it hard to predict how much time we could buy under different scenarios.

###

The other co-authors are Benjamin Smith at the UW and Brooke Medley, who did her doctorate at the UW and is now at NASA's Goddard Space Flight Center. The research was funded by the National Science Foundation and NASA.

For more information, contact Joughin at 206-221-3177 or ian@apl.washington.edu.

Hannah Hickey | Eurek Alert!
Further information:
http://www.washington.edu

Further reports about: Antarctic Antarctica Glacier Physics measurements

More articles from Earth Sciences:

nachricht NASA eyes Pineapple Express soaking California
24.02.2017 | NASA/Goddard Space Flight Center

nachricht 'Quartz' crystals at the Earth's core power its magnetic field
23.02.2017 | Tokyo Institute of Technology

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>