On Wednesday, July 12, scientists confirmed that the largest documented iceberg, roughly the size of Delaware and surpassing a weight of one trillion tonnes, now drifts through the Weddell Sea after breaking off from the Antarctic Peninsula. Although Project MIDAS attributes the breakup to a natural process called “calving,” others believe the event could be detrimental to the structure of the remaining ice shelf, Larsen C. In the context of rising ocean temperatures and sea levels due to greenhouse gases, where the West Antarctic ice sheet is currently the most vulnerable, the collapse of these structures poses a very real threat to our coastal cities around the world.
According to the New York Times article released on Wednesday, Project MIDAS, a British research team, has been observing a growing rift in Larsen C since 2014. When the crack reached the coastline at over 120 miles long, scientists began to worry for the structural integrity of the Antarctic Peninsula. It is believed that the remainder of Larsen C will ultimately collapse if it ever surpasses the boundary known as the compressive arch, explained Jugal Patel and Justin Gillis in their story. Even though sea levels would face minimal impact from the deterioration of this shelf, like Larsens A and B before it, these floating bodies of ice function as natural buttresses slowing down the movement of glaciers into our warming, ocean waters. Glaciologist Eric Rignot from the University of California, Irvine, explained to Science Magazine the big picture of the threat posed by Larsen C’s eventual disintegration:
“As climate warming advances farther south, it will affect larger and larger ice shelves that currently hold back bigger and bigger glaciers,” said Rignot. “So their collapse will contribute more to sea level rise.”
Of course, the fluctuation of ice has become a significant concern for those seeking to study the effects of human activity. This past May, four dispatched journalists from the New York Times returned from their flight with Columbia University scientists to report on the accelerated movement of ice across West Antarctica. The second part of this article series notes that Ross, the ice shelf in question, approximately the size of Texas, was already deteriorating by the 90s and has tripled its rate of ice loss since then. For the time being, this shelf appears stable; but due to its bowl-shaped nature, mostly below sea level, the second in the dispatch series warns that the West Antarctic is particularly vulnerable to global warming. And if greenhouse gas emissions continue at their current rate, coastal cities like London, Istanbul, New York, and Hong Kong might not see the ocean’s surface 100 years from now.
If the Ross Ice Shelf completely collapses before the 22nd century, as worst-case simulations predict, sea levels could raise by 6 feet, potentially even 10-15 feet as other unstable bodies of ice follow suit. The primary question in circulation, Richard Alley from Pennsylvania State University proposed, is at what temperature the ice will start to collapse past the point of return – and whether or not global warming has already achieved it.