MAY 20 (Reuters) — The last intact section of one of Antarctica’s mammoth ice shelves is weakening fast and will likely disintegrate completely in the next few years, contributing further to rising sea levels, according to a NASA study released on Thursday (May 14).
The research focused on a remnant of the so-called Larsen B Ice Shelf, which has existed for at least 10,000 years but partially collapsed in 2002. What is left covers about 625 square miles (1,600 square km), about half the size of Rhode Island.
“This ice shelf that we know had existed for at least 11 or 12 thousand years, in 2002 two thirds of it collapsed in less than six weeks and we found now that this remaining part also will disintegrate within years at the most and it means that it will be gone. A structure in Antarctica that existed for so long will be gone in just a very, very short period of time relative to how long it had existed before and this is a clear indication of the enormity of changes that are taking place in the Antarctic Peninsula and elsewhere in Antarctica,” said Ala Khazendar, the study’s lead scientist.
Antarctica has dozens of ice shelves – massive, glacier-fed floating platforms of ice that hang over the sea at the edge of the continent’s coast line. The largest is roughly the size of France.
Larsen B is located in the Antarctic Peninsula, which extends toward the southern tip of South America and is one of two principal areas of the continent where scientists have documented the thinning of such ice formations.
“It’s probably already affecting sea levels. From our study now we know that these glaciers are flowing faster and most likely they are putting more ice into the ocean,” said Khazendar.
Almost 200 countries have agreed to negotiate a United Nations pact by the end of 2015 to combat global climate change, which most scientists expect will bring about more flooding, droughts, heat waves and higher seas.
The U.N. Intergovernmental Panel on Climate Change has cited a probability of at least 95 percent that accelerated warming of the planet has been triggered by human activities, led by atmospheric emissions of greenhouse gases from the burning of fossil fuels.
The study, published online in the journal Earth and Planetary Science Letters, was based on airborne surveys and radar data.
While Khazendar cannot give a specific date for the final collapse of Larsen B he is sure it will be gone within a few years.
“I mean, since we published the paper we’ve already noticed more cracks in the ice because with our colleagues we’re continuing, as I mentioned, to work on the ice shelf. So, even after submitting the paper and going through the review process and all that we started continuing our work and we’ve already noticed more of these big rifts opening in the ice shelf that were not even there or that we were not aware of when we were doing the work that appeared eventually in this particular study. So, it’s happening fast and it’s just a matter of years.”
The study also found Leppard and Flask, two main tributary glaciers of the ice shelf, have thinned by between 65 and 72 feet (20 to 22 meters) in recent years, and the pace of their shrinking has accelerated since the immediate aftermath of the 2002 partial collapse of the ice shelf. (Pasadena, California, United States)