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

    Vietnam Urges US to Lift Lethal Weapons Ban Amid S. China Sea Tensions

    US president’s upcoming visit to Vietnam underscores strength of relationship, and lifting embargo would reflect that trust, ambassador says

    Are US Schools Turning a Blind Eye to Radical Qatari Preachers?

    Parade of radical Islamist clerics using mosque at Qatar’s Education City draws mounting criticism for American universities that maintain satellite branches there

    Why Islamic State Is Down But Not Out

    Despite loss of territory, group’s ferocious attacks over past three months seen as testimony to its continued durability and resourcefulness

    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.
    Displaced By War, Syrian Artist Finds Inspiration Abroadi
    X
    May 02, 2016 1:36 PM
    Saudi-born Syrian painter Mohammad Zaza is among the millions who fled their home for an uncertain future after Syria's civil war broke out. Since fleeing Syria, Zaza has lived in Lebanon, Egypt, Jordan and now Turkey where his latest exhibition, “Earth is Blue like an Orange,” opened in Istanbul. He spoke with VOA about how being displaced by the Syrian civil war has affected the country's artists.
    Video

    Video Displaced By War, Syrian Artist Finds Inspiration Abroad

    Saudi-born Syrian painter Mohammad Zaza is among the millions who fled their home for an uncertain future after Syria's civil war broke out. Since fleeing Syria, Zaza has lived in Lebanon, Egypt, Jordan and now Turkey where his latest exhibition, “Earth is Blue like an Orange,” opened in Istanbul. He spoke with VOA about how being displaced by the Syrian civil war has affected the country's artists.
    Video

    Video Ethiopia’s Drought Takes Toll on Children

    Ethiopia is dealing with its worst drought in decades, thanks to El Nino weather patterns. An estimated 10 million people urgently need food aid. Six million of them are children, whose development may be compromised without sufficient help, Marthe van der Wolf reports for VOA from the Metahara district.
    Video

    Video Little Havana - a Slice of Cuban Culture in Florida

    Hispanic culture permeates everything in Miami’s Little Havana area: elderly men playing dominoes as they discuss politics, cigar rollers deep at work, or Cuban exiles talking with presidential candidates at a Cuban coffee window. With the recent rapprochement between Cuba and United States, one can only expect stronger ties between South Florida and Cuba.
    Video

    Video California Republicans Weigh Presidential Choices Amid Protests

    Republican presidential candidates have been wooing local party leaders in California, a state that could be decisive in selecting the party's nominee for U.S. president. VOA's Mike O’Sullivan reports delegates to the California party convention have been evaluating choices, while front-runner Donald Trump drew hundreds of raucous protesters Friday.
    Video

    Video Kurdish Football Team Helps War-Torn City Cope

    With the conflict still raging across much of Turkey’s predominantly Kurdish southeast, between the rebel PKK and the Turkish state, many Kurds are trying to escape the turmoil by focusing on the success of their football team Amedspor in Diyarbakir. The club is increasingly becoming a symbol for Kurds, not only in Diyarbakir but beyond. Dorian Jones reports from southeast Turkey.
    Video

    Video ‘The Lights of Africa’ - Through the Eyes of 54 Artists

    An exhibition bringing together the work of 54 African artists, one from each country, is touring the continent after debuting at COP21 in Paris. Called "Lumières d'Afrique," the show centers on access to electricity and, more figuratively, ideas that enlighten. Emilie Iob reports from Abidjan, the exhibition's first stop.
    Video

    Video Pakistani School Helps Slum Kids

    Master Mohammad Ayub runs a makeshift school in a public park in Islamabad. Thousands of poor children have benefited from his services over the years, but, as VOA's Ayesha Tanzeem reports, roughly 25 million school-age youths don't get an education in Pakistan.
    Video

    Video Florida’s Weeki Wachee ‘Mermaids’ Make a Splash

    Since 1947, ‘mermaids’ have fascinated tourists at central Florida’s Weeki Wachee Springs State Park with their fluid movements and synchronized ballet. Performing underwater has its challenges, including cold temperatures and a steady current, as VOA’s Lin Yang and Joseph Mok report.
    Video

    Video Somali, African Union Forces Face Resurgent Al-Shabab

    The Islamic State terror group claimed its first attack in Somalia earlier this week, though the claim has not been verified by forces on the ground. Meanwhile, al-Shabab militants have stepped up their attacks as Somalia prepares for elections later this year. Henry Ridgwell reports there are growing frustrations among Somalia’s Western backers over the country’s slow progress in forming its own armed forces to establish security after 25 years of chaos.
    Video

    Video Documentary Tells Tale of Chernobyl Returnees

    Ukraine this week is marking the 30th anniversary of the world's worst nuclear accident, at the Chernobyl nuclear power plant. Soviet officials at first said little about the accident, but later evacuated a 2,600-square-kilometer "exclusion zone." Some people, though, came back. American directors Holly Morris and Anne Bogart created a documentary about this faithful and brave community. VOA's Tetiana Kharchenko reports from New York on "The Babushkas of Chernobyl." Carol Pearson narrates.
    Video

    Video Nigerians Feel Bite of Buhari Economic Policy

    Despite the global drop in the price of oil, Nigerian President Muhammadu Buhari has refused to allow the country's currency to devalue, leading to a shortage of foreign exchange. Chris Stein reports from Lagos businessmen and consumers are feeling the impact as the country deals with a severe fuel shortage.
    Video

    Video  Return to the Wild

    There’s a growing trend in the United States to let old or underused golf courses revert back to nature. But as Erika Celeste reports from one parcel in Grafton, Ohio, converting 39 hectares of land back to green space is a lot more complicated than just not mowing the fairway.

    Special Report

    Adrift The Invisible African Diaspora