News / Science & Technology

Warm Ocean Accelerating Antarctic Ice Loss

The ice front of Venable Ice Shelf, West Antarctica, in October 2008, is an example of a small-size ice shelf that is a large melt water producer.
The ice front of Venable Ice Shelf, West Antarctica, in October 2008, is an example of a small-size ice shelf that is a large melt water producer.
Rosanne Skirble
Summer ice loss in parts of Antarctica is at its highest in 1,000 years, according to a new study which finds that the melt is coming largely from underneath ice shelves, the floating edges of the ice sheet that extend over the ocean.

The study is the first comprehensive survey of all the Antarctic ice shelves, which are the 1.5 million square kilometers that fringe much of the frozen continent. 

Lead author Eric Rignot, a professor at the University of California, Irvine, says ice melt from below accounted for 55 percent of the shelf loss from 2003 to 2008, a rate much higher than previously thought.   

“We find that the melting of the underside of the ice shelves is even larger than the production of icebergs," Rignot said. "So it is the dominant process of ice removal in the Antarctic.”  

Listen now:
Antarctic Ice Shelf Melt from Bottom Upi
|| 0:00:00
...
 
🔇
X

Rignot and colleagues used satellite observations, radar and computer models to measure features above the ice to calculate what was going on below.  

“That includes the velocity of the ice, the thickness of the ice, how fast the freeboard [height of ice above sea level] of the ice shelf is changing with time and also how much snowfall there is on the top of the ice shelves,” Rignot said.

The measurements showed regional differences around the continent. The giant ice shelves - Ross, Filchner and Ronne - make up two-thirds of Antarctica’s ice shelves, yet accounted for only 15 percent of the melting.
Calving front of an ice shelf in West Antarctica taken on a NASA mission focused on gatering data for the new ice shelf study.Calving front of an ice shelf in West Antarctica taken on a NASA mission focused on gatering data for the new ice shelf study.
Meanwhile, a dozen small ice shelves, which sit on relatively warmer water, produced half the total water from ice melt during the same period.                                                                                                                                                                                                                                                                                           
 “That means that in a regime of climate warming where the properties of the Southern Ocean are changing, they may be changing faster than other oceans in the world," Rignot said. "We may be in a situation where the coastline of Antarctica may be changing at a faster pace than we thought in the past.”  

The ocean is a very sensitive system, according to Rignot, and even small shifts, like changes in ocean circulation driven by wind, can make a huge difference in ice shelf melt.
Ice front of the ice shelf in front of Pine Island Glacier, a major glacier system of West Antarctica.Ice front of the ice shelf in front of Pine Island Glacier, a major glacier system of West Antarctica.
“If the wind regime changes in the Southern Ocean, it is going to change the way the ocean heat is distributed on the coast, and that’s going to affect glaciers,” he said.

Sixty percent of the planet’s fresh water is locked in the massive Antarctic ice sheet. Rignot says the study will help scientists predict how the continent responds to a warmer ocean and contributes to global sea level rise.  

“I think that it places more emphasis on the enormous importance of ice-ocean interaction in the Antarctic," he said. "If we really want to understand how these ice shelves evolve and will evolve in the future we must understand how the ocean is contributing to their melting in the underside.”

You May Like

Video Experts Warn World Losing Ebola Fight

Doctors Without Borders says world is losing battle against Ebola, unless wealthy nations dispatch specialized biological disaster response teams More

Video Experts: Rise of Islamic State Significant Development in Jihadism

Many analysts contend the group - which grew out of al-Qaida in Iraq - has been rebuilding for years More

US-Based Hong Kongers Pledge Support for Pro-Democracy Activists

Democracy advocates call on Chinese living abroad to join them in opposing new election rules for their home territory More

This forum has been closed.
Comment Sorting
Comments
     
by: Richard Pauli from: Seattle, Wa
June 14, 2013 11:49 PM
Thank you so much VOA for this excellent report. It is news, it is important and we need to be watching this carefully.

There is so little coverage of climate change in broadcast and in newspapers, you are filling an important need. Thanks.


Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Larger Than Life Chinese Lanterns Make Southern California Appearancei
X
Elizabeth Lee
September 02, 2014 8:57 PM
Chinese lanterns with a long history are lighting up in 21st century style at the Los Angeles County Fair in southern California. Visitors can see traditional lanterns that hang, but also lanterns in the shape of animals, iconic landmarks and many other objects, all created by artisans from a place in China known for its lanterns. Elizabeth Lee has the details from the fair in the city of Pomona.
Video

Video Larger Than Life Chinese Lanterns Make Southern California Appearance

Chinese lanterns with a long history are lighting up in 21st century style at the Los Angeles County Fair in southern California. Visitors can see traditional lanterns that hang, but also lanterns in the shape of animals, iconic landmarks and many other objects, all created by artisans from a place in China known for its lanterns. Elizabeth Lee has the details from the fair in the city of Pomona.
Video

Video Experts See Rise of ISIS as Significant Development

The Islamic State’s rise seems sudden. It caught the U.S. by surprise this summer when it captured large portions of northern Iraq and spread its wings in neighboring Syria. But many analysts contend that the group - which grew out of al-Qaida in Iraq - has been rebuilding for years. VOA's Jela de Franceschi takes a closer look at the rise of ISIS and its implications for the Middle East and beyond.
Video

Video Israel Concerned Over Syrian Rebels in Golan

Israeli officials are following with concern the recent fighting between Syrian rebels and government forces near the contested Golan Heights. Forty-four U.N. peacekeepers from Fiji have been seized by Syrian Islamist rebels and the clashes occasionally have spilled into Israel. VOA’s Scott Bobb reports from Jerusalem.
Video

Video Ukraine Schools Resume Classes, Donate to Government Forces

A new school year has started in Ukraine but thousands of children in the war-torn east are unable to attend because of ongoing clashes with pro-Russia rebels. In Ukraine's capital, patriotic education has become the norm along with donations to support injured security forces fighting to take back rebel-held areas. VOA's Daniel Schearf reports from Kyiv.
Video

Video US Detainees Want Negotiators for Freedom in North Korea

The three U.S. detainees held in North Korea were permitted to speak with foreign media Monday. The government of Kim Jong Un restricted the topics of the questions, and the interviews in Pyongyang were limited to five minutes. Each of the men asked Washington to send a representative to Pyongyang to secure his release. VOA’s Carolyn Presutti has our story.
Video

Video Turkmen From Amerli Describe Survival of IS Siege

Over the past few weeks, hundreds of Shi'ite Turkmen have fled the town of Amerli seeking refuge in the northern city of Kirkuk. Despite recent military gains after U.S. airstrikes that were coordinated with Iraqi and Kurdish forces, the situation remains dire for Amerli’s residents. Sebastian Meyer went to Kirkuk for VOA to speak to those who managed to escape.
Video

Video West Africa Ebola Vaccine Trials Possible by Early 2015

A U.S. health agency is speeding up clinical trials of a possible vaccine against the deadly Ebola virus that so far has killed more than 1,500 people in West Africa. If successful, the next step would be a larger trial in countries where the outbreak is occurring. VOA's Carol Pearson has more.
Video

Video Survivors Commemorate 70th Anniversary of Nazi Liquidation of Jewish Ghetto

When the German Nazi army occupied the Polish city of Lodz in 1939, it marked the beginning of a long nightmare for the Jewish community that once made up one third of the population. Roughly 200,000 people were forced into the Lodz Ghetto. Less than 7,000 survived. As VOA’s Kane Farabaugh reports, some survivors gathered at the Union League Club in Chicago on the 70th anniversary of the liquidation of the Lodz Ghetto to remember those who suffered at the hands of the Nazi regime.

AppleAndroid