Iceberg half the size of Wales floats free

A satellite camera has captured an iceberg half the size of Wales breaking off from an Antarctic ice shelf. Scientists believe it is one of the biggest icebergs on record.

The iceberg, which has broken off from the Ross Ice Shelf, is estimated to cover more than 4,000 square miles, measuring 183 miles long and 23 miles wide. The images were taken from 700km up in space by the American NOAA-12 polar-orbiting satellite.

"This is a very big iceberg, close to a record if not a new record. It's not often that you seem them of this magnitude," said Matthew Lazzara, of the University of Wisconsin at Madison. Iceberg "calving" is a natural phenomenon and results from the continual movement towards the Antarctic shore of ice and snow that falls over the frozen continent.

David Vaughan, a glaciologist from the British Antarctic Survey, said the iceberg captured by a polar-orbiting satellite operated by the American National Oceanic and Atmospheric Administration may just fail to break the record.

Dr Vaughan said: "It's a big one but its not the biggest. I've had it on good authority that there have been larger icebergs in the past."

Dr Vaughan said scientists have expected to see large icebergs break off from the Ross shelf, which faces the Pacific, because they have been relatively rare events over the past 10 years. At present, Dr Vaughan said, there is no evidence to suggest huge icebergs are the result of global warming, although in other parts of Antarctica, such as the Wordie and Larsen shelves on the Antarctic Peninsula, there is evidence to suggest that warmer temperatures are causing the ice to recede.