Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Recent Climate, Glacier Changes in Antarctica at the 'Upper Bound' of Normal

15.04.2013
In the last few decades, glaciers at the edge of the icy continent of Antarctica have been thinning, and research has shown the rate of thinning has accelerated and contributed significantly to sea level rise.

New ice core research suggests that, while the changes are dramatic, they cannot be attributed with confidence to human-caused global warming, said Eric Steig, a University of Washington professor of Earth and space sciences.

Previous work by Steig has shown that rapid thinning of Antarctic glaciers was accompanied by rapid warming and changes in atmospheric circulation near the coast. His research with Qinghua Ding, a UW research associate, showed that the majority of Antarctic warming came during the 1990s in response to El Niño conditions in the tropical Pacific Ocean.

Their new research suggests the '90s were not greatly different from some other decades – such as the 1830s and 1940s – that also showed marked temperature spikes.

"If we could look back at this region of Antarctica in the 1940s and 1830s, we would find that the regional climate would look a lot like it does today, and I think we also would find the glaciers retreating much as they are today," said Steig, lead author of a paper on the findings published online April 14 in Nature Geoscience.

The researchers' results are based on their analysis of a new ice core from the West Antarctic Ice Sheet Divide that goes back 2,000 years, along with a number of other ice core records going back about 200 years. They found that during that time there were several decades that exhibited similar climate patterns as the 1990s.

The most prominent of these in the last 200 years – the 1940s and the 1830s – were also periods of unusual El Niño activity like the 1990s. The implication, Steig said, is that rapid ice loss from Antarctica observed in the last few decades, particularly the '90s, "may not be all that unusual."

The same is not true for the Antarctic Peninsula, the part of the continent closer to South America, where rapid ice loss has been even more dramatic and where the changes are almost certainly a result of human-caused warming, Steig said.

But in the area where the new research was focused, the West Antarctic Ice Sheet, it is more difficult to detect the evidence of human-caused climate change. While changes in recent decades have been unusual and at the "upper bound of normal," Steig said, they cannot be considered exceptional.

"The magnitude of unforced natural variability is very big in this area," Steig said, "and that actually prevents us from answering the questions, 'Is what we have been observing exceptional? Is this going to continue?'"

He said what happens to the West Antarctic Ice Sheet in the next few decades will depend greatly on what happens in the tropics.

The West Antarctic Ice Sheet is made up of layers of ice, greatly compressed, that correspond with a given year's precipitation. Similar to tree rings, evidence preserved in each layer of ice can provide climate information for a specific time in the past at the site where the ice core was taken.

In this case, the researchers detected elevated levels of the isotope oxygen 18 in comparison with the more commonly found oxygen 16. Higher levels of oxygen 18 generally indicate higher air temperatures.

Levels of oxygen 18 in ice core samples from the 1990s were more elevated than for any other time in the last 200 years, but were very similar to levels reached during some earlier decades.

The work was funded by the National Science Foundation Office of Polar Programs.

For more information, contact Steig at 206-685-3715, 206-543-6327 or steig@uw.edu.

An image of a section of the West Antarctic Ice Sheet Divide core is available from vinces@uw.edu.

Co-authors are Qinghua Ding, Marcell Küttel, Peter Neff, Ailie Gallant, Spruce Schoenemann, Bradley Markle, Tyler Fudge, Andrew Schauer and Rebecca Teel of the University of Washington; James White and Bruce Vaughn of the University of Colorado; Summer Rupper, Landon Burgener and Jessica Williams of Brigham Young University; Thomas Neumann of NASA's Goddard Space Flight Center; Paul Mayewski, Daniel Dixon and Elena Korotkikh of the University of Maine; Kendrick Taylor of Desert Research Institute, Reno, Nev.; Georg Hoffmann of the Centre d'Etudes de Saclay in France and Utrecht University in The Netherlands; and David Schneider of the National Center for Atmospheric Research, Boulder, Colo.

Vince Stricherz | Newswise
Further information:
http://www.uw.edu

More articles from Earth Sciences:

nachricht Predicting eruptions using satellites and math
28.06.2017 | Frontiers

nachricht NASA sees quick development of Hurricane Dora
27.06.2017 | 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: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Mice provide insight into genetics of autism spectrum disorders

28.06.2017 | Health and Medicine

New photoacoustic technique detects gases at parts-per-quadrillion level

28.06.2017 | Physics and Astronomy

Funding of Collaborative Research Center developing nanomaterials for cancer immunotherapy extended

28.06.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>