Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

West Antarctica ice sheet existed 20 million years earlier than previously thought

05.09.2013
The results of research conducted by professors at UC Santa Barbara and colleagues mark the beginning of a new paradigm for our understanding of the history of Earth's great global ice sheets.

The research shows that, contrary to the popularly held scientific view, an ice sheet on West Antarctica existed 20 million years earlier than previously thought.


Adelie penguins walk in file on sea ice in front of US research icebreaker Nathaniel B. Palmer in McMurdo Sound. Credit: John Diebold

The findings indicate that ice sheets first grew on the West Antarctic subcontinent at the start of a global transition from warm greenhouse conditions to a cool icehouse climate 34 million years ago. Previous computer simulations were unable to produce the amount of ice that geological records suggest existed at that time because neighboring East Antarctica alone could not support it. The findings were published today in Geophysical Research Letters, a journal of the American Geophysical Union.

Given that more ice grew than could be hosted only on East Antarctica, some researchers proposed that the missing ice formed in the northern hemisphere, many millions of years before the documented ice growth in that hemisphere, which started about 3 million years ago. But the new research shows it is not necessary to have ice hosted in the northern polar regions at the start of greenhouse-icehouse transition.

Earlier research published in 2009 and 2012 by the same team showed that West Antarctica bedrock was much higher in elevation at the time of the global climate transition than it is today, with much of its land above sea level. The belief that West Antarctic elevations had always been low lying (as they are today) led researchers to ignore it in past studies. The new research presents compelling evidence that this higher land mass enabled a large ice sheet to be hosted earlier than previously realized, despite a warmer ocean in the past.

"Our new model identifies West Antarctica as the site needed for the accumulation of the extra ice on Earth at that time," said lead author Douglas S. Wilson, a research geophysicist in UCSB's Department of Earth Science and Marine Science Institute. "We find that the West Antarctic Ice Sheet first appeared earlier than the previously accepted timing of its initiation sometime in the Miocene, about 14 million years ago. In fact, our model shows it appeared at the same time as the massive East Antarctic Ice Sheet some 20 million years earlier."

Wilson and his team used a sophisticated numerical ice sheet model to support this view. Using their new bedrock elevation map for the Antarctic continent, the researchers created a computer simulation of the initiation of the Antarctic ice sheets. Unlike previous computer simulations of Antarctic glaciation, this research found the nascent Antarctic ice sheet included substantial ice on the subcontinent of West Antarctica. The modern West Antarctic Ice Sheet contains about 10 percent of the total ice on Antarctica and is similar in scale to the Greenland Ice Sheet.

West Antarctica and Greenland are both major players in scenarios of sea level rise due to global warming because of the sensitivity of the ice sheets on these subcontinents. Recent scientific estimates conclude that global sea level would rise an average of 11 feet should the West Antarctic Ice Sheet melt. This amount would add to sea level rise from the melting of the Greenland ice sheet (about 24 feet).

The UCSB researchers computed a range of ice sheets that consider the uncertainty in the topographic reconstructions, all of which show ice growth on East and West Antarctica 34 million years ago. A surprising result is that the total volume of ice on East and West Antarctica at that time could be more than 1.4 times greater than previously realized and was likely larger than the ice sheet on Antarctica today.

"We feel it is important for the public to know that the origins of the West Antarctic Ice Sheet are under increased scrutiny and that scientists are paying close attention to its role in Earth's climate now and in the past," concluded co-author Bruce Luyendyk, UCSB professor emeritus in the Department of Earth Science and research professor at the campus's Earth Research Institute.

Other co-authors include David Pollard of the Earth and Environmental Systems Institute at Pennsylvania State University, Robert M. DeConto of the Department of Geosciences at the University of Massachusetts, Amherst, and Stewart S.R. Jamieson of the Department of Geography at Durham University in the United Kingdom.

The National Science Foundation's Office of Polar Programs and the United Kingdom's Natural Environment Research Council supported this research.

Julie Cohen | EurekAlert!
Further information:
http://www.ia.ucsb.edu

More articles from Earth Sciences:

nachricht A promising target in the quest for a 1-million-year-old Antarctic ice core
24.05.2018 | University of Washington

nachricht Tropical Peat Swamps: Restoration of Endangered Carbon Reservoirs
24.05.2018 | Leibniz-Zentrum für Marine Tropenforschung (ZMT)

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Powerful IT security for the car of the future – research alliance develops new approaches

The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.

Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

In focus: Climate adapted plants

25.05.2018 | Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

 
Latest News

In focus: Climate adapted plants

25.05.2018 | Event News

Flow probes from the 3D printer

25.05.2018 | Machine Engineering

Less is more? Gene switch for healthy aging found

25.05.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>