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 Novel method for investigating pore geometry in rocks
18.06.2018 | Kyushu University, I2CNER

nachricht Decades of satellite monitoring reveal Antarctic ice loss
14.06.2018 | University of Maryland

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Overdosing on Calcium

Nano crystals impact stem cell fate during bone formation

Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...

Im Focus: AchemAsia 2019 will take place in Shanghai

Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.

Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...

Im Focus: First real-time test of Li-Fi utilization for the industrial Internet of Things

The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.

Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.

Im Focus: Sharp images with flexible fibers

An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.

Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...

Im Focus: Photoexcited graphene puzzle solved

A boost for graphene-based light detectors

Light detection and control lies at the heart of many modern device applications, such as smartphone cameras. Using graphene as a light-sensitive material for...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Munich conference on asteroid detection, tracking and defense

13.06.2018 | Event News

2nd International Baltic Earth Conference in Denmark: “The Baltic Sea region in Transition”

08.06.2018 | Event News

ISEKI_Food 2018: Conference with Holistic View of Food Production

05.06.2018 | Event News

 
Latest News

Carbon nanotube optics provide optical-based quantum cryptography and quantum computing

19.06.2018 | Physics and Astronomy

How to track and trace a protein: Nanosensors monitor intracellular deliveries

19.06.2018 | Life Sciences

New material for splitting water

19.06.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>