Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


The shield is crumbling


Over the past 20 years, many ice shelves in Antarctica have shrunk and some have disappeared entirely. This has resulted in a significant acceleration of many Antarctic glaciers, contributing to rising sea levels. Dr. Johannes Fürst from the Institute of Geography at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) has used a complex model to show for the first time at what point the “buttressing” role of ice shelves is impaired due to their decline. The results of Dr. Fürst's research, carried out in collaboration with Antarctic experts from Laboratoire de Glaciologie et Géophysique de l'Environnement in Grenoble, France, have been published in the journal Nature Climate Change*.

Antarctica is surrounded by huge ice shelves. The largest of these, the Ross Ice Shelf, has an area comparable to the size of Spain. These ice shelves are several hundred metres thick and float on the surface of the sea, towering above the water.

Calving front of the Fleming Glacier which fed into the Wordie Ice Shelf before it collapsed in the late 1980s. One can discern the high calving activity characterising the post-collapse period.

Photo: Matthias Braun

They are firmly linked to glaciers and ice streams on mainland Antarctica. These ice shelves are naturally fed by upstream inflow from tributary glaciers which push the floating ice seawards. Away from the mainland, at the seaward fronts of these ice shelves, ice breaks off as vast icebergs which drift away. This loss of ice is usually compensated for by land ice flowing in to replace it. This natural balance prevailed for thousands of years.

Ice-shelf retreat since 1995

However, over the past 20 years, researchers observed the progressive retreat and break-up of ice shelves on the Antarctic Peninsula. In 1995, Larsen A Ice Shelf collapsed completely removing the ice-cover from an area the size of Berlin. Seven years later, the much larger Larsen B Ice Shelf broke apart. This disintegration had hardly any immediate effect on sea levels as the lost ice was already afloat.

However, upstream tributary glaciers flowing towards the ocean accelerated by up to eight times after the break-up events on Larsen A and B. 'In contrast to the situation in Greenland, the loss of inland ice in West Antarctica is not caused by melting. It is much too cold for that to happen,' Johannes Fürst explains. 'The decrease is due to the glaciers there flowing into the sea at a faster rate than 20 years ago. This is what we call dynamic ice loss.'

Long-term sea-level rise

If all the ice shelves surrounding Antarctica were to collapse, this would result in rapid dynamic loss of inland ice, which would entail an elevated Antarctic contribution to sea-level rise for decades to come. Originally working at the LGGE in Grenoble, Johannes Fürst has now spent several years investigating how the presence of ice shelves exerts control on the upstream glacier dynamics. ‘As ice shelves continuously lose ice by calving, it is essential to known how far the recession of ice shelves may progress before the buttressing potential is reduced,' he says.

The West-Antarctic underbelly

For the whole of Antarctica, ice velocity data inferred from satellite images, including images of the European Space Agency (ESA), and airborne observations on ice thickness were analysed by Fürst, using an Elmer/Ice flow model developed in a collaborative effort between France (LGGE) and Finland (CSC). This enabled him to calculate that about 13 per cent of the total ice-shelf area contains so-called passive shelf ice. 'Passive shelf ice is the part of the floating ice body which provides no additional buttressing,' he explains.

'It is this portion which, when lost by calving, will not trigger an instant velocity increase.' His analysis reveals contrasting results across the continent. Along the coast of Queen Maud Land, ice shelves still have a relatively large and ‘healthy’ portion of passive ice. They are thus considered rather stable, for now. In the Bellingshausen and Amundsen Seas, this portion is much smaller. For some ice shelves, it is already almost absent.

'We expect that further ice-shelf retreat there will instantly produce dynamic changes, which may well give rise to increased ice outflow from the mainland,' Fürst explains. 'This is worrying because it is in this region that we have observed the highest rates of ice-shelf thinning over the past two decades and dynamic ice loss in the inland areas upstream.'

*Nature Climate Change: The safety band of Antarctic ice shelves, Johannes Jakob Fürst, Gaël Durand, Fabien Gillet-Chaulet, Laure Tavard, Melanie Rankl, Matthias Braun and Olivier Gagliardini. DOI:

Dr. Johannes Fürst
Phone: +49 9131 8526680

Dr. Susanne Langer | idw - Informationsdienst Wissenschaft
Further information:

More articles from Earth Sciences:

nachricht Receding glaciers in Bolivia leave communities at risk
20.10.2016 | European Geosciences Union

nachricht UM researchers study vast carbon residue of ocean life
19.10.2016 | University of Miami Rosenstiel School of Marine & Atmospheric Science

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

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

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>