1 trillion ton iceberg breaks off Antarctica ice shelf, scientists say

LONDON -- A vast iceberg with twice the volume of Lake Erie has broken off from a key floating ice shelf in Antarctica, scientists said Wednesday.

The iceberg broke off from the Larsen C ice shelf, scientists at the University of Swansea in Britain said. The iceberg is described as weighing 1 trillion tons (1.12 trillion U.S. tons).

The process, known as calving, occurred in the last few days, when a 5,800-square-kilometer (2,240-square-mile) section broke away.

"We have been anticipating this event for months, and have been surprised how long it took for the rift to break through the final few kilometers of ice," said Adrian Luckman of Swansea University. "We will continue to monitor both the impact of this calving event on the Larsen C Ice Shelf, and the fate of this huge iceberg."

It was a natural event that wasn't caused by man-made climate change, said Swansea glaciologist Martin O'Leary.

Nonetheless, "this puts the ice shelf in a very vulnerable position," he said in a statement.

Scientists said the latest iceberg break won't affect sea levels in the short term.

NASA and European Space Agency satellites have been monitoring the shelf - offering dramatic pictures of the break that heightened interest beyond the scientific community. The final break was first revealed in a thermal infrared image from NASA's Aqua MODIS satellite instrument.

Scientists from the U.K.-based Antarctic project, MIDAS, have been monitoring the rift in Larsen C for years, following earlier research on the collapse of the Larsen A shelf in 1995 and the breakup of the Larsen B shelf in 2002.

The project, which is investigating the effects of a warming climate through a combination of fieldwork, satellite observation and computer simulation, describes the iceberg as one of the largest ever recorded.

The researchers suggest the iceberg is likely to break into fragments and say that while some of the ice may stay nearby for decades, parts of it may drift north into warmer waters. But researchers say much more study needs to be done to determine the cause.

"At this point it would be premature to say that this was caused by global warming," said Anna Hogg of the Centre for Polar Observation and Modelling at the University of Leeds.