In yet another blow to our ability to slow climate change has occurred in the highly vulnerable West Antarctica ice shelves. This iceberg is more than 100 miles in size — 4 times the size of Manhattan- and it broke off the Pine Island Glacier (PIG). PIG holds 1.7 feet of global sea level rise (SLR) and by adding the ice of Thwaites Glacier a gut wrenching SLR of 10 feet. This will only add more fury to powerful tropical storms creating even bigger human catastrophes that boggle the mind with their devastation to coastal cities throughout the world.
This break is not natural and it happens to be the fifth largest ice chunk loss from PIG since 2000. This crack had formed unnoticed at the very base of the ice shelf miles inland.
The Pine Island Glacier and, “the Thwaites Glacier, sit at the outer edge of one of the most active ice streams on the continent”. They provide a buttressing effect to the ice stream, by creating a backward stress that balances the downward stress of the ice trying to flow out to sea.
This is not the first time an inland ice break has occurred at PIG. The AGU reported on a 2015 break that also had a similar result due to human caused warming, from fossil fuel emissions, of the Southern ocean.
“Rifts usually form at the margins of an ice shelf, where the ice is thin and subject to shearing that rips it apart,” he explained. “However, this latest event in the Pine Island Glacier was due to a rift that originated from the center of the ice shelf and propagated out to the margins. This implies that something weakened the center of the ice shelf, with the most likely explanation being a crevasse melted out at the bedrock level by a warming ocean.”
Another clue: The rift opened in the bottom of a “valley” in the ice shelf where the ice had thinned compared to the surrounding ice shelf.
The valley is likely a sign of something researchers have long suspected: Because the bottom of the West Antarctic Ice Sheet lies below sea level, ocean water can intrude far inland and remain unseen. New valleys forming on the surface would be one outward sign that ice was melting away far below.
Yale 360 reports on the September 2017 break.
Scientists told The Washington Post that they are monitoring Pine Island Glacier closely for signs that its ice loss may be speeding up. Pine Island alone has the potential to raise global sea level 1.7 feet if it melts completely, The Post reported. In 2015, the glacier lost a piece of ice 220 square miles in size, and recent calving events are originating farther and farther inland, Stef Lhermitte, a satellite observation scientist at Delft University of Technology in the Netherlands, tweeted.
In a paper published last year, scientists reported that rifts in the Pine Island Glacier were originating in the middle and underneath its floating ice shelf, not along its face, which is generally how pieces of ice calve from a glacier. The researchers theorized this was because warmer ocean waters are reaching farther underneath the base of the glacier and the ice shelf.
“We predicted that the rifting would result in more frequent calving, which is what’s happening here,” Ian Howat, a climate scientist at Ohio State University and co-author of the 2016 study, told The Post. “If new rifts continue to form progressively inland, the significance to ice shelf retreat would be high.”
Perhaps the saddest part of this story is that Donald Trump does not give a flying fu@k about climate change and the human catastrophes that it unleashes.