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Associated Press, 4/17/98 - 9:36 PM EDT
Section of Antarctic Ice Shelf Breaks Off

A massive chunk of ice shelf on the Antarctic Peninsula broke away earlier this year and scientists on Friday blamed global warming. Satellite images of the Larsen B ice shelf, which reaches toward South America, show the section broke away between Feb. 26 and March 23, toward the end of the Antarctic summer, according to the U.S. National Snow and Ice Data Center in Boulder, Colo. The icebergs produced by the crumbled shelf pose no particular threat, since there are no major shipping lanes in that area and Antarctic cruise ships or those resupplying bases all have radar to detect icebergs.

The collapse of the 75-square-mile chunk of ice shelf is consistent with "what we see from the effects of increased greenhouse gases, which cause warming," said Bill Budd, a meteorology professor at Australia's Antarctic Cooperative Research Center. "And it's the warming in the ocean that is most important for the reduction in the ice shelves," he said. "It is the melting from underneath that can be much more effective than warming of the air."

The British Antarctic Survey has predicted the entire Larsen Ice Shelf, which covers more than 4,000 square miles, is nearing its limit of stability. In January 1995, the Larsen A ice shelf to the north broke away in a 48 mile-by-23 mile mass, 600 feet thick. Over the past 50 years, the Antarctic Peninsula has warmed about 4.5 degrees. Research by Budd and his colleagues indicates global warming will melt most of the ice shelves, which border about 44 percent of Antarctica and cover 580,000 square miles. Budd's computer climate models predict significant degradation of the ice shelves beginning in the 21st century and their near-total loss within 500 years.

NOAA 98-69
For Immediate Release: 10/15/98
New Iceberg Breaks Off Ronne Ice Shelf in Antartica

An iceberg larger than the state of Delaware has broken off the Ronne Ice Shelf in Antarctica, the National Ice Center reported today. The iceberg, named A-38, is 92 x 29.9 miles and covers an area roughly 2750.8 square miles. It broke off the second largest ice shelf in Antarctica, located in the southern Weddell Sea.

Large Iceberg Breaks Free from Antarctica, September 29, 2000

An iceberg 10 times the size of Manhattan Island has broken free from Antarctica's Ross Ice Shelf, The National Ice Center reported Friday. Iceberg B-20, as it is identified by the ice center, was discovered Wednesday by satellite monitoring. The exact date the 345-square-mile berg broke off the ice shelf could not be determined because of cloudiness in the area but it is thought to have been between Sept. 20 and 26. The 30-mile-long, 11.5-mile-wide iceberg is in the Ross Sea, south of the Pacific Ocean. The Ross Ice Shelf, on the part of Antarctica closest to Australia and New Zealand, is one of two massive ice fields on the continent that have been the site of increased "calving" of huge icebergs. While Iceberg B-20 is large, it is dwarfed by others that have separated from the Ross and Ronne Ice Shelves in recent years. Many scientists have speculated that the increase in the separation of ice from the Antarctic continent is caused by human-induced global warming, but few claim firm scientific evidence to support that. Whatever the cause, the introduction of land-based ice from Antarctica into ocean waters could have some impact on sea levels. Marine safety experts warn that an increase in icebergs off Antarctica, in the North Atlantic and along cold-water shorelines like Alaska's Prince William Sound could raise the risk of ships colliding with icebergs. None of the Antarctic icebergs are currently in the path of heavily used shipping lanes.