Saturday June 17, 2017

An iceberg the size of P.E.I. is about to break off Antarctica

A rift across the Larsen C Ice Shelf that had grown longer and deeper is seen during an airborne surveys of changes in polar ice over the Antarctic Peninsula.

A rift across the Larsen C Ice Shelf that had grown longer and deeper is seen during an airborne surveys of changes in polar ice over the Antarctic Peninsula. (NASA/Reuters)

Listen 8:38

This week a team of Canadian scientists heading to the Arctic were forced to abort part of their mission when they encountered severe ice conditions on their way there.The conditions were too treacherous for even an icebreaker to get through. 

But that ice in the water is nothing compared to the massive chunk that's about to break off in Antarctica - an iceberg the size of Prince Edward Island. A massive crack on the Larsen C Antarctic ice shelf first noticed decades ago has been opening up at an accelerating rate in recent years.  And just a few weeks ago, it jumped again — opening up 17 kilometres in just six days.  

Larsen C ice shelf

The current location of the rift on Larsen C, as of May 31 2017 (A. Luckman/MIDAS project, Swansea University)

At time of our show, this massive chunk of ice is hanging by a thread  —  the crack has only less than 13 kilometres to go before this giant piece of ice completely separates, and drifts out into the sea.

Dr. Dan McGrath is a research geophysicist at the United States Geological Survey - Alaska Science Centre, as well as at Colorado State University in Fort Collins, Colorado. He says ice sheets like Larsen C are like buttresses that hold in the ice from the glaciers, stopping the glaciers from moving out to sea. While he says they're not expecting this calving event of this huge iceberg-to-be itself to destabilize the rest of the Larsen C ice shelf, it is not out of the question. 

And while this iceberg coming from Larsen C will be massive, Dr. McGrath is more concerned about the fate of the larger ice sheets in Western Antarctica as they are showing more vulnerability. He'll be keeping a close eye on how the rift propagates along Larsen C because it's essentially a great natural laboratory to see what happens elsewhere on the Antarctic ice.