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 NASA's AIM observes early noctilucent ice clouds over Antarctica
05.12.2016 | NASA/Goddard Space Flight Center

nachricht GPM sees deadly tornadic storms moving through US Southeast
01.12.2016 | NASA/Goddard Space Flight Center

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

High-precision magnetic field sensing

05.12.2016 | Power and Electrical Engineering

Construction of practical quantum computers radically simplified

05.12.2016 | Information Technology

NASA's AIM observes early noctilucent ice clouds over Antarctica

05.12.2016 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>