Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Analysis exposes faster disintegration of major Greenland glacier

13.11.2015

A study appearing in Science magazine today shows a vast ice sheet in northeast Greenland has begun a phase of speeded-up ice loss, contributing to destabilization that will cause global sea-level rise for "decades to come."

A team of scientists, including a researcher from the University of Kansas-based Center for Remote Sensing of Ice Sheets (CReSIS), found that since 2012 warmer air and sea temperatures have caused the Zachariæ Isstrøm ice sheet to "retreat rapidly along a downward-sloping, marine-based bed."


This is radar depth-sounder data from before and after the breakup of the Zachariæ Isstrøm ice shelf. The green line reveals the ice bottom, and loss of ice between 1999-2014. The white line represents hydrostatic equilibrium estimates of the ice bottom.

Credit: KU News Service | University of Kansas

By itself, the Zachariæ Isstrøm glacier holds enough water to trigger a half-meter rise in ocean levels around the world.

"The acceleration rate of its ice velocity tripled, melting of its residual ice shelf and thinning of its grounded portion doubled, and calving is occurring at its grounding line," the authors wrote.

"Ice loss is happening fast in glaciological terms, but slow in human terms -- not all in one day or one year," said John Paden, associate scientist for CReSIS and courtesy associate professor of electrical engineering and computer science at KU, who helped analyze data about the thickness of the glacier's ice for the study.

Paden's collaborators include J. Mouginot, E. Rignot, B. Scheuchl, M. Morlighem and A. Buzzi from the University of California Irvine, along with I. Fenty and A. Khazendar of the California Institute of Technology.

"Within a few generations, ice loss could make a substantial difference in sea levels," Paden said. "When you add up all the glaciers that are retreating, it will make a difference to a large number of people. Sea level has increased some over the last century, but only a small number of people have been affected compared to what is likely to come."

Paden crunched data acquired by CReSIS during NASA's Operation IceBridge and previous NASA flights over Greenland, including decades-old measurements of Zachariæ Isstrøm. The sensor development and data processing tools used to do this were funded through National Science Foundation and NASA grants, with the support of many CReSIS collaborators.

"There are several other sources of data, but one of them is the Landsat satellite imagery that goes back to 1975," Paden said. "With that, you can look at what the ice shelf is doing, how it's shrinking over time. Satellite optical and radar imagery were used to measure surface-velocity changes over time and to measure the position of the grounding line based on tidal changes."

Paden said the "grounding line," or the boundary between land and sea underneath a glacier, is a zone of special interest.

"The grounding line is where the ice sheet starts to float and is where the ice flux was measured," Paden said. "The grounding line is a good place to determine thickness across the ice. The terminus of Zachariæ Isstrøm is now at the grounding line -- the ocean is right up against the grounded part of the glacier."

While air temperatures have warmed, causing boosted surface runoff, Paden said ice loss from calving off the front of the glacier into the ocean accounts for most of the ice mass reduction from Zachariæ Isstrøm.

"Ice floating out into the ocean and melting is greater than the ice lost from surface melting," he said.

A neighboring glacier with an equal amount of ice, named Nioghalvfjersfjorden, is also melting fast but receding gradually along an uphill bed, according to the researchers. Because Zachariæ Isstrøm is on a downslope, it's disappearing faster.

"The downward slope combined with warming ocean temperatures is what seems to be causing the acceleration now and why we predict it will continue to accelerate over the next few decades," Paden said. "Until its grounding line is pinned on an upslope bed, then the dynamic effect is expected to decrease."

Together, the ice in Zachariæ Isstrøm and Nioghalvfjersfjorden represent a 1.1-meter rise in sea levels worldwide. According to the KU researcher, the team's work is intended to inform people in coastal areas who need to make choices about the future.

"From a societal standpoint, the reason why there's so much focus on ice sheets is because predicted sea level rise will affect nearly every coastal country -- the United States for sure, and low-lying countries with limited resources are likely to be the worst off. Mass displacements of potentially millions of people will affect countries that have no coastlines. We study this to have an understanding of how soon things are likely to happen and to help us use our limited resources mitigate the problem."

Media Contact

Brendan M. Lynch
brendan@ku.edu
785-864-8855

 @KUNews

http://www.news.ku.edu 

Brendan M. Lynch | EurekAlert!

More articles from Earth Sciences:

nachricht Six-decade-old space mystery solved with shoebox-sized satellite called a CubeSat
15.12.2017 | National Science Foundation

nachricht NSF-funded researchers find that ice sheet is dynamic and has repeatedly grown and shrunk
15.12.2017 | National Science Foundation

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: First-of-its-kind chemical oscillator offers new level of molecular control

DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.

Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Engineers program tiny robots to move, think like insects

15.12.2017 | Power and Electrical Engineering

One in 5 materials chemistry papers may be wrong, study suggests

15.12.2017 | Materials Sciences

New antbird species discovered in Peru by LSU ornithologists

15.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>