Scientists announced Wednesday that an iceberg with a volume twice that of Lake Erie has broken away from the Larsen C ice shelf in Antarctica. University of Michigan scientists can discuss the event and its significance.
Jeremy Bassis studies iceberg calving as an associate professor in the Department of Climate and Space Sciences and Engineering. Bassis has studied similar ice rifts in the Amery Ice Shelf in east Antarctica, exploring why some cracks grow and others do not. He is involved in efforts with the British Antarctic Survey to conduct on-the-ground seismology studies of smaller cracks in Larsen C.
"As far as what will happen next in this region of Antarctica, the honest answer is nobody knows," Bassis said. "We don't know if the ice shelf will be semi-stable, slowly disappear over decades or disappear relatively quickly.
"There are a few possible scenarios. One is that ice shelves like Larsen C, continuously every few decades, break off big icebergs and nothing about this is unusual. It could be part of the advance-and-retreat life cycle of the ice shelf and it may just continue business as usual. The second possibility is that it may have retreated to a position that's further back than it's been before and this may be part of a trend in which the shelf slowly disintegrates as more bergs detach. The third possibility is that it becomes like the Larsen B shelf, in that what looks like business as usual might precipitate a rapid disintegration event: A whole bunch of rifts could become more active and the entire ice shelf could disintegrate.
"At this point, it's really important to monitor the rifts that exist on the remaining ice shelf and see whether they're becoming more active."
Mac Cathles is an adjunct lecturer and research fellow in the U-M Department of Climate and Space Sciences and Engineering. He studies the processes acting at the boundaries of ice sheets, ice shelves and glaciers—including iceberg calving dynamics.
Cathles is developing tools to remotely measure the mass loss that occurs when icebergs break away from ice sheets. Having the ability to measure glacier calving remotely will improve the reliability of models that predict future sea-level rise in a warming climate.
He studied a similar-size iceberg that calved off the Ross Ice Shelf in Antarctica.
"It is unclear if this latest calving event is 'business as usual' or will destabilize the remaining Larsen C ice shelf," he said. "But I think there is a lot we will be able to learn from studying how this iceberg detached from Larsen C, and by watching how the remaining ice shelf responds after this calving event."