London - One of the biggest icebergs on
record has broken away from Antarctica, scientists said on
Wednesday, creating an extra hazard for ships around the
continent as it breaks up.
The one trillion tonne iceberg, measuring 5 800 square km,
calved away from the Larsen C Ice Shelf in Antarctica sometime
between July 10 and 12, said scientists at the University of
Swansea and the British Antarctic Survey.
The iceberg, which is roughly the size of the US state of
Delaware or the Indonesian island of Bali, has been close to
breaking off for a few months.
Throughout the Antarctic winter, scientists monitored the
progress of the rift in the ice shelf using the European Space
Agency satellites.
A February 2017 image of the Larsen C ice shelf in Antarctica made available by the Antarctic Survey. Picture: British Antarctic Survey via AP
"The iceberg is one of the largest recorded and its future
progress is difficult to predict," said Adrian Luckman,
professor at Swansea University and lead investigator of Project
MIDAS, which has been monitoring the ice shelf for years.
"It may remain in one piece but is more likely to break into
fragments. Some of the ice may remain in the area for decades,
while parts of the iceberg may drift north into warmer waters,"
he added.
The ice will add to risks for ships now it has broken off.
The peninsula is outside major trade routes but the main
destination for cruise ships visiting from South America.
In 2009, more than 150 passengers and crew were evacuated
after the MTV Explorer sank after striking an iceberg off the
Antarctic peninsula.
The iceberg, which is likely to be named A68, was already
floating before it broke away so there is no immediate impact on
sea levels, but the calving has left the Larsen C ice shelf
reduced in area by more than 12 percent.
The Larsen A and B ice shelves, which were situated further
north on the Antarctic Peninsula, collapsed in 1995 and 2002,
respectively.
"This resulted in the dramatic acceleration of the glaciers
behind them, with larger volumes of ice entering the ocean and
contributing to sea-level rise," said David Vaughan,
glaciologist and director of science at British Antarctic
Survey.
"If Larsen C now starts to retreat significantly and
eventually collapses, then we will see another contribution to
sea level rise," he added.
Big icebergs break off Antarctica naturally, meaning
scientists are not linking the rift to manmade climate change.
The ice, however, is a part of the Antarctic peninsula that has
warmed fast in recent decades.
"In the ensuing months and years, the ice shelf could either
gradually regrow, or may suffer further calving events which may
eventually lead to collapse – opinions in the scientific
community are divided," Luckman said.
"Our models say it will be less stable, but any future
collapse remains years or decades away."