The Heat Is Online

Scientists Discover Further Disintegration of Antarctic Ice Shelves

In 1995, a Rhode-Island sized section of the Larsen Ice Shelf broke off from Antarctica due to ocean warming. In the following year, scientists discovered that five of the nine ice shelves attached to the Antarctic Peninsula have disintegrated over the last half century, as temperatures have risen. In the spring of 1998, a second huge section of the same ice shelf collapsed into the ocean.

Researchers David Vaughan and C. S. M. Doake of the British Antarctic survey, wrote in the journal Nature in January, 1996, that surface temperatures in the Antarctic peninsula have increased by 4 to 5 degrees F. in the last fifty years. That temperature increase -- which is five times more than the worldwide increase -- has caused five coastal ice shelves to break up.

"People talk a lot about global warming in terms of average temperature," Vaughan told the Boston Globe, "but the impact is going to be local areas where the climate changes very significantly. If Antarctica experiences above average temperature increases," he added, "it could begin a process that significantly raises the Earth’s sea level." If the polar ice sheet continues to break up, it would add significantly to the three-foot sea level rise already predicted by the world’s climate scientists for the next century.

Vaughan and Doake caution that if the warming continues, it could trigger the melting of ancient ice sheets in the interior of Antarctica.

H. Jay Zwally, a glaciologist at the Goddard Space Flight Center, told the Globe "If this is a precursor of what might happen on an expanded scale in the Antarctica, it would become far more serious in the future. He pointed out that at the end of the last Ice Age 10,000 years ago, melting ice raised sea levels by 30 feet in only a few hundred years.

While scientists do not agree on the rate and extent of global warming caused by burning fossil fuels, Dr. Rodolfo del Valle of Argentina’s National Antarctic Institute, thinks greenhouse gases might be dangerously accelerating a natural warming process in the region. "I think the process is like a father pushing his child in a swing. If the father pushes too hard, the swing twists around, the child falls down and the game is over.'"

Citation:

"Melting ice stirs fear on warming," Boston Globe, Jan. 25, 1996; "Ice Shelves Melting as Forecast, but Disaster Script Is in Doubt," New York Times, Jan. 30,1996.

In March, 1998, another section of the Larsen Ice Shelf – about 25 miles by three miles – broke off from Antarctica.

On April 16, satellite pictures were released by US scientists which showed that a big section of the Larsen B Antarctic ice shelf has broken off and the whole mass may now rapidly crumble. Last year a Greenpeace expedition to the Antarctic peninsula documented large cracks along the Larsen B Ice Shelf which independent scientists identified as a sign of imminent collapse. The scientists from the University of Colorado at Boulder's National Snow and Ice Data Center said a section about 25 miles (40 kms) long and three miles (5 kms) wide had broken off the Larsen B Ice Shelf. The researchers said their pictures seemed to confirm earlier studies by the British Antarctic Survey that predicted the 4,800 square mile (12,000 sq km) ice shelf was nearing its limits of stability.

Scientists say global warming has been steadily shrinking the Antarctic ice shelves. Regional temperatures have risen an average of 4.5 degrees Fahrenheit (2.5 degrees Centigrade) since the 1940s. A smaller ice shelf area called the Larsen A completely disintegrated during a single storm in 1995 after years of gradually shrinking.

Citation:

Collapse Of Portion of Antarctic Ice Shelf Gives Warning to Governments on Climate Change: Greenpeace Press Release: April 17, 1998.