JUL 12, 2017

Is Larsen C's calving a sign of climate change?

WRITTEN BY: Kathryn DeMuth Sullivan

The Larsen C ice shelf has been flirting with dismantlement from Western Antarctica for months now, and in the last few days, its departure from mainland Antarctica has been confirmed. The iceberg, which weighs more than one trillion tons and covers 5,800 square kilometers in area, has been being monitored by scientists from Project MIDAS via NASA's Aqua MODIS satellite. Although such calving is considered normal behavior for icebergs, the event has put many on edge, questioning how climate change has played a role in releasing this immense ice shelf out to sea. 


But Luckman and other scientists have been hesitant to pull the climate change correlation trigger, saying "We have no evidence to link this directly to climate change, and no reason to believe that it would not have happened without the extra warming that human activity has caused." Although Luckman points out in his piece published in The Conversation that calving ice shelves are by no means a sign of climate change, there still are some climate factors involved in both the before-and-after process. 


Luckman writes that ice shelves are particularly intriguing geologically because they can only survive in areas only where the climate is chilly enough to sustain the ice as it drifts by. This means that ice shelves are unique mostly to Antarctica. Also critical to note is that ice shelves act as natural barriers for the mainland, effectively reducing the flow of glaciers into the ocean and regulating sea level rise. Furthermore, Luckman writes, “In a warming world, ice shelves are of particular scientific interest because they are susceptible both to atmospheric warming from above and ocean warming from below.”


However, scientists have stressed that the calving will not cause immediate sea level rise, as the ice was already floating on the ocean before it detached. "This event does not directly affect anyone, and repercussions, if there are any, will not be felt for years. However, it is a spectacular and enormous geographical event which has changed the landscape," said Professor Adrian Luckman from Swansea University, the leader of the MIDAS project. "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. Icebergs are routinely monitored by various agencies, and they will be keen to keep track of this one," Luckman stated.


Larsen C, as you might have guessed from its name, was not the first to go; Larsen A and B calved in 1995 and 2002. But Larsen C is special in its grand size. With a volume twice as large as Lake Erie’s, it covers an area three times that of the greater London area. But it’s area has already faced reduction by 12% now that it is in the open ocean. It is likely that warmer waters have, at least, played a role in that. 

Sources: The Conversation, CNN, The Guardian