Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Threat from West Antarctica less than previously believed

18.05.2009
The potential contribution to sea level rise from a collapse of the West Antarctic Ice Sheet (WAIS) have been greatly overestimated, according to a new study published in the journal Science.

Scientists estimate global sea level would rise 3.3 metres, not five or six, as previously thought. The Atlantic and Pacific seaboards of the US, even in the case of a partial collapse, would experience the largest increases, threatening cities such as New York, Washington DC and San Francisco.

Long thought of as the sleeping giant with respect to sea level rise, Antarctica holds about nine times the volume of ice of Greenland. Its western ice sheet is of particular interest to scientists due to its unusual below-sea level topography, which is believed to make it inherently unstable. But the area's potential contribution to sea level has been greatly overestimated, according to new calculations.

Professor Jonathan Bamber at Bristol University, lead author of the study, said: "There's a vast body of research that's looked at the likelihood of a WAIS collapse and what implications such a catastrophic event would have for the globe. Yet all of these studies have assumed a five- to-six-metre contribution to sea level rise. Our calculation shows those estimates are much too large, even on a thousand year timescale."

Jonathan Bamber, Professor in Physical Geography, at the University's School of Geographical Sciences is currently a Visiting Fellow at the University of Colorado at Boulder's Cooperative Institute for Research in Environmental Sciences, or CIRES.

Instead of assuming a complete disintegration of the whole WAIS, Bamber and colleagues used models, based on glaciological theory, to simulate how the massive ice sheet would respond if the floating ice shelves fringing the continent broke free. Vast ice shelves currently block the WAIS from spilling into the Weddell and Ross Seas, limiting total ice loss to the ocean.

According to theory, if these floating ice shelves were removed, sizeable areas of the WAIS would become, in effect, undammed, triggering an acceleration of the ice sheet towards the ocean and a "rapid" inland migration of the grounding line, the point where the ice sheet's margins meets the ocean and begins to float.

The most unstable areas of the WAIS are those grounded below sea level on bedrock with negative bedslope, where the bedrock slopes downwards inland. Once undammed, these areas would quickly become buoyant, forming new floating ice shelves further inland and, in time, precipitating further break up and collapse.

For their calculations, the researchers assumed that only these areas would collapse and contribute to sea level rise. In contrast, they assumed areas grounded above sea level, or on bedrock that slopes upwards inland, would likely retain substantial ice masses.

Professor Bamber said: "Unlike the world's other major ice sheets – the East Antarctic Ice Sheet and Greenland – WAIS is the only one with such an unstable configuration."

Just how "rapid" a collapse of the WAIS would be is largely unknown. Though if such a large mass of ice steadily melted over 500 years, as suggested in an early study, it would add about 6.5 millimetres per year to sea level rise: twice the current rate due to all sources.

Professor Bamber added: "Interestingly, the pattern of sea level rise is independent of how fast or how much of the WAIS collapses. Even if the WAIS contributed only a metre of sea level rise over many years, sea levels along North America's shorelines would still increase 25 per cent more than the global average."

Regional variations in sea level would be largely driven by the redistribution of ice mass from the Antarctic continent to the oceans, according to the study. With less mass at the South Pole, Earth's gravity field would weaken in the Southern Hemisphere and strengthen in the North, causing water to pile up in the northern oceans.

This redistribution of mass would also affect Earth's rotation, which in turn would cause water to build up along the North American continent and in the Indian Ocean.

The study was conducted with support from the National Environmental Research Council (NERC) and in collaboration with Delft University of Technology in the Netherlands and the University of Durham.

Joanne Fryer | EurekAlert!
Further information:
http://www.bristol.ac.uk

More articles from Studies and Analyses:

nachricht A sudden drop in outdoor temperature increases the risk of respiratory infections
11.01.2017 | University of Gothenburg

nachricht Urbanization to convert 300,000 km2 of prime croplands
27.12.2016 | Mercator Research Institute on Global Commons and Climate Change (MCC) gGmbH

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

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

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Explaining how 2-D materials break at the atomic level

18.01.2017 | Materials Sciences

Data analysis optimizes cyber-physical systems in telecommunications and building automation

18.01.2017 | Information Technology

Reducing household waste with less energy

18.01.2017 | Ecology, The Environment and Conservation

VideoLinks
B2B-VideoLinks
More VideoLinks >>>