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 Smart Data Transformation – Surfing the Big Wave
02.12.2016 | Fraunhofer-Institut für Angewandte Informationstechnik FIT

nachricht Climate change could outpace EPA Lake Champlain protections
18.11.2016 | University of Vermont

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: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

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...

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

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>