Featured Research

from universities, journals, and other organizations

Antarctic Ice Shelves Breaking Up Due To Decades Of Higher Temperatures

Date:
April 9, 1999
Source:
University Of Colorado At Boulder
Summary:
Two ice shelves on the Antarctic Peninsula known as the Larsen B and Wilkins are in "full retreat" and have lost nearly 3,000 square kilometers of their total area in the last year, say scientists in Colorado and the United Kingdom.

Two ice shelves on the Antarctic Peninsula known as the Larsen B and Wilkins are in "full retreat" and have lost nearly 3,000 square kilometers of their total area in the last year, say scientists in Colorado and the United Kingdom.

Researchers at the University of Colorado at Boulder's National Snow and Ice Data Center and the British Antarctic Survey attribute the retreats to a regional warming trend. The trend has caused the annual melt season to increase by two to three weeks over the last 20 years, they said.

Satellite photos monitored by NSIDC show that the Larsen B ice shelf has continued to crumble after an initial small retreat in spring 1998. In a series of events that began in November 1998, an additional 1,714 square kilometers of shelf area caved away, said Research Associate Ted Scambos of CU-Boulder's NSIDC.

On the opposite side of the peninsula, the Wilkins Ice Shelf retreated nearly 1,100 square kilometers in early March of last year, said Scambos.

Scientists looking at weather satellite imagery at that time suspected a breakup was underway and had their suspicions confirmed by radar satellite images.

"The radar images showed a large area of completely shattered ice, indicating an ice front 35 kilometers back from its previous extent," said Scambos. "The sudden appearance of thousands of small icebergs suggests that the shelves are essentially broken up in place and then flushed out by storms or currents afterward."

The British Antarctic Survey scientists had predicted one of these retreats, using computer models to demonstrate that the Larsen B was nearing its stability limit. With the small breakup observed last spring, the shelf had already retreated too far to continue to be supported by adjacent islands and shorelines.

Scientists at both institutes expected the two shelves to fail soon, but the current disintegration is occurring at an even faster rate than earlier breakups gave reason to anticipate.

"We have evidence that the shelves in this area have been in retreat for 50 years, but those losses amounted to only about 7,000 square kilometers," said David Vaughan, a researcher with the Ice and Climate Division of the British Antarctic Survey. "To have retreats totaling 3,000 square kilometers in a single year is clearly an escalation. Within a few years, much of the Wilkins ice shelf will likely be gone."

Ice shelves are floating plates of ice that are still attached to continents and which form when large glaciers flow toward the ocean in polar areas. Where they are supported by islands and sheltering coastline, they can become stable, long-term features, said Scambos.

Surface features on the Larsen B indicate that it has existed for at least 400 years. But as climate inches toward an average summertime temperature just above 0 degrees C -- the melting point of water -- the Larsen and Wilkins ice shelves have begun to disintegrate.

The Larsen B ice shelf is currently about 7,000 square kilometers -- about the size of Delaware. The Wilkins ice shelf is nearly twice that large, Scambos said.

The British researchers, who have monitored the peninsula's climate warming for decades, report an increase in mean annual temperature of about 2.5 degrees C or roughly 4.5 degrees F since the 1940's. Both groups concur that ice shelf breakup is a direct result of local climate warming.

According to Scambos, the recent warming trend has led to greater amounts of ponding melt on the shelf, weakening it. "Melt water at the surface acts to increase the extent of fracturing in the ice," he said. "The weight of the water essentially forces the cracks open, so a relatively small amount of climate warming can destroy a large, centuries-old ice shelf."

###The NSIDC is part of the Cooperative Institute for Research in Environmental Sciences, a joint venture of CU-Boulder and the National Oceanic and Atmospheric Administration. Images of the Larsen B and Wilkins ice sheets are available at the following web sites:

http://www-nsidc.colorado.edu/NSIDC/ICESHELVES/lars_wilk_news

http://www.nerc-bas.ac.uk


Story Source:

The above story is based on materials provided by University Of Colorado At Boulder. Note: Materials may be edited for content and length.


Cite This Page:

University Of Colorado At Boulder. "Antarctic Ice Shelves Breaking Up Due To Decades Of Higher Temperatures." ScienceDaily. ScienceDaily, 9 April 1999. <www.sciencedaily.com/releases/1999/04/990409073216.htm>.
University Of Colorado At Boulder. (1999, April 9). Antarctic Ice Shelves Breaking Up Due To Decades Of Higher Temperatures. ScienceDaily. Retrieved October 23, 2014 from www.sciencedaily.com/releases/1999/04/990409073216.htm
University Of Colorado At Boulder. "Antarctic Ice Shelves Breaking Up Due To Decades Of Higher Temperatures." ScienceDaily. www.sciencedaily.com/releases/1999/04/990409073216.htm (accessed October 23, 2014).

Share This



More Earth & Climate News

Thursday, October 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

San Diego Zoo's White Rhinos Provide Hope for the Critically Endangered Species

San Diego Zoo's White Rhinos Provide Hope for the Critically Endangered Species

Reuters - Light News Video Online (Oct. 22, 2014) — The pair of rare white northern rhinos bring hope for their species as only six remain in the world. Elly Park reports. Video provided by Reuters
Powered by NewsLook.com
Trick-or-Treating Banned Because of Polar Bears

Trick-or-Treating Banned Because of Polar Bears

Buzz60 (Oct. 21, 2014) — Mother Nature is pulling a trick on the kids of Arviat, Canada. As Mara Montalbano (@maramontalbano) tells us, the effects of global warming caused the town to ban trick-or-treating this Halloween. Video provided by Buzz60
Powered by NewsLook.com
Traditional Farming Methods Gaining Ground in Mali

Traditional Farming Methods Gaining Ground in Mali

AFP (Oct. 20, 2014) — He is leading a one man agricultural revolution in Mali - Oumar Diatabe uses traditional farming methods to get the most out of his land and is teaching others across the country how to do the same. Duration: 01:44 Video provided by AFP
Powered by NewsLook.com
How Detroit's Money Woes Led To U.N.-Condemned Water Cutoffs

How Detroit's Money Woes Led To U.N.-Condemned Water Cutoffs

Newsy (Oct. 20, 2014) — The United Nations says water is a human right, but should it be free? Detroit has cut off water to residents who can't pay, and the U.N. isn't happy. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins