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

    Escalation of Media Crackdown in Turkey Heightens Concerns

    Critics see 'a new dark age' as arrests of journalists, closures of media outlets by Erdogan government mount

    Russia Boasts of Troop Buildup on Flank, Draws Flak

    Russian military moves counter to efforts to de-escalate tensions, State Department says

    Video Iraqis Primed to March on Mosul, Foreign Minister Says

    Iraqi FM Ibrahim al-Jaafari tells VOA the campaign will meet optimistic expectations, even though US officials remain cautious

    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.
    Immigrant Delegate Marvels at Democratic Processi
    X
    Katherine Gypson
    July 27, 2016 6:21 PM
    It’s been a bitter and divisive election season – but first time Indian-American delegate Dr. Shashi Gupta headed to the Democratic National Convention with a sense of hope. VOA’s Katherine Gypson followed this immigrant with the love of U.S. politics all the way to Philadelphia.
    Video

    Video Immigrant Delegate Marvels at Democratic Process

    It’s been a bitter and divisive election season – but first time Indian-American delegate Dr. Shashi Gupta headed to the Democratic National Convention with a sense of hope. VOA’s Katherine Gypson followed this immigrant with the love of U.S. politics all the way to Philadelphia.
    Video

    Video A Life of Fighting Back: Hillary Clinton Shatters Glass Ceiling

    Hillary Clinton made history Thursday, overcoming personal and political setbacks to become the first woman to win the presidential nomination of a major U.S. political party. If she wins in November, she will go from “first lady” to U.S. Senator from New York, to Secretary of State, to “Madam President.” Polls show Clinton is both beloved and despised. White House Correspondent Cindy Saine takes a look at the life of the woman both supporters and detractors agree is a fighter for the ages.
    Video

    Video Dutch Entrepreneurs Turn Rainwater Into Beer

    June has been recorded as one of the wettest months in more than a century in many parts of Europe. To a group of entrepreneurs in Amsterdam the rain came as a blessing, as they used the extra water to brew beer. Serginho Roosblad has more to the story.
    Video

    Video First Time Delegate’s First Day Frustrations

    With thousands of people filling the streets of Philadelphia, Pennsylvania for the 2016 Democratic National Convention, VOA’s Kane Farabaugh narrowed in on one delegate as she made her first trip to a national party convention. It was a day that was anything but routine for this United States military veteran.
    Video

    Video Commerce Thrives on US-Mexico Border

    At the Democratic Convention in Philadelphia this week, the party’s presumptive presidential nominee, Hillary Clinton, is expected to attack proposals made by her opponent, Republican presidential nominee Donald Trump, to build a wall along the U.S.-Mexico border. Last Friday, President Barack Obama hosted his Mexican counterpart, President Enrique Peña Nieto, to underscore the good relations between the two countries. VOA’s Greg Flakus reports from Tucson.
    Video

    Video Film Helps Save Ethiopian Children Thought to be Cursed

    'Omo Child' looks at effort of African man to stop killings of ‘mingi’ children
    Video

    Video London’s Financial Crown at Risk as Rivals Eye Brexit Opportunities

    By most measures, London rivals New York as the only true global financial center. But Britain’s vote to leave the European Union – so-called ‘Brexit’ – means the city could lose its right to sell services tariff-free across the bloc, risking its position as Europe’s financial headquarters. Already some banks have said they may shift operations to the mainland. Henry Ridgwell reports from London.
    Video

    Video Recycling Lifeline for Lebanon’s Last Glassblowers

    In a small Lebanese coastal town, one family is preserving a craft that stretches back millennia. The art of glass blowing was developed by Phoenicians in the region, and the Khalifehs say they are the only ones keeping the skill alive in Lebanon. But despite teaming up with an eco-entrepreneur and receiving an unexpected boost from the country’s recent trash crisis the future remains uncertain. John Owens reports from Sarafand.
    Video

    Video Migrants Continue to Risk Lives Crossing US Border from Mexico

    In his speech Thursday before the Republican National Convention, the party’s presidential candidate, Donald Trump, reiterated his proposal to build a wall along the U.S.-Mexico border if elected. Polls show a large percentage of Americans support better control of the nation's southwestern border, but as VOA’s Greg Flakus reports from the border town of Nogales in the Mexican state of Sonora, the situation faced by people trying to cross the border is already daunting.
    Video

    Video In State of Emergency, Turkey’s Erdogan Focuses on Spiritual Movement

    The state of emergency that Turkish President Recep Tayyip Erdogan has declared is giving him even more power to expand a purge that has seen an estimated 60,000 people either arrested or suspended from their jobs. VOA Europe correspondent Luis Ramirez reports from Istanbul.
    Video

    Video Calm the Waters: US Doubles Down Diplomatic Efforts in ASEAN Meetings

    The United States is redoubling diplomatic efforts and looking to upcoming regional meetings to calm the waters after an international tribunal invalidated the legal basis of Beijing's extensive claims in the South China Sea. VOA State Department correspondent Nike Ching has the story.
    Video

    Video Scientists in Poland Race to Save Honeybees

    Honeybees are in danger worldwide. Causes of what's known as colony collapse disorder range from pesticides and loss of habitat to infections. But scientists in Poland say they are on track to finding a cure for one of the diseases. VOA’s George Putic reports.

    Special Report

    Adrift The Invisible African Diaspora