Massive iceberg breaks away from Antarctica's Larsen C ice shelf

Thursday, 13 Jul, 2017

A massive iceberg almost four times the size of Greater London has broken away from Antarctica.

Big icebergs break off Antarctica naturally, meaning scientists are not linking the rift to manmade climate change.

An aerial view of the rift in the Larsen C seen in an image from the Digital Mapping System over the Antarctica Peninsula, Antarctica.

While this iceberg alone won't have a devastating effect, and the ultimate fate of Larsen C is far from known, it does point to the alarming possibility that Larsen C and other ice shelves could collapse in response to human-caused global warming.

Scientists discovered the birth of this iceberg in data collected by an instrument aboard NASA's Aqua satellite, called MODIS, which takes thermal infrared images.

Scientists from the United Kingdom -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 iceberg that broke off of it made up roughly 12% of its total volume. This non-floating ice would have an eventual impact on sea levels, but only at a modest rate, explained MIDAS.

Map showing iceberg detachment based on data from NASA dated July 12
Map showing iceberg detachment based on data from NASA dated July 12

The vulnerable chunk of ice reportedly weighs more than 1 trillion tons and measures a concerning 5,800 square kilometers (about 2,239 square miles). Although many scientists believed that climate change has made the cracks grow quicker, the event is best described as a geographical event rather than a climate event.

They announced Wednesday on their Project MIDAS blog that it appears the iceberg calved sometime between July 10 and 12.

Larsen C is the fourth largest ice shelf in Antarctica with an area of about 20,000 square miles according to NASA.

The iceberg may remain unified but could break into smaller icebergs, professor Adrian Luckman, the project's lead investigator, said in a statement.

"This is the furthest back that the ice front has been in recorded history", O'Leary said.

"We will study the ice shelf for signs that it is reacting to the calving - but we do not expect anything much to happen for perhaps years". While warmer water or air temperatures have been an important factor in controlling the size of many Antarctic ice shelves, there's no indication that climate change has played a significant role in the calving of this specific iceberg.