A critical Antarctic glacier appears more vulnerable as satellite images show that the ice shelf that prevents it from collapsing into the sea is breaking much faster than before and spawning huge icebergs, according to a new study.
The loss of sea ice from the Pine Island Glacier accelerated in 2017, leading scientists to fear that with climate change, the glacier’s collapse could occur faster than many centuries had predicted. The floating pack ice acts as a plug in a bottle for the rapidly melting glacier and prevents its much larger mass of ice from flowing into the ocean.
This ice shelf retreated 12 miles (20 kilometers) between 2017 and 2020, according to a study published Friday in Science Advances. And the crumbling shelf was caught on time-lapse video from a European satellite that takes pictures every six days.
“You can see things tearing apart,” said lead author of the study, Ian Joughin, a glaciologist at the University of Washington. “So it almost seems that the acceleration itself is weakening the glacier. … And so far we’ve lost maybe 20% of the main shelf.
Between 2017 and 2020, there were three major rupture events, creating icebergs more than 5 miles long and 36 miles wide, which then split into many smaller chunks, Joughin said. There were also a lot of small ruptures.
“It is not at all inconceivable that the entire plateau could give way and disappear within a few years,” Joughin said. “I would say it’s far, but not very far.”
Joughin tracked two points on the main glacier and found they were moving 12% faster towards the sea as of 2017.
“So that means 12% more Pine Island ice in the ocean than there was before,” he said.
The Pine Island Glacier, which is not on a pineless island, is one of two coast-to-coast glaciers in West Antarctica that ice scientists are most worried about losing on that continent. The other is the Thwaites Glacier.
Pine Island contains 180 trillion tonnes of ice – the equivalent of 1.6 feet (half a meter) of sea level rise – and is responsible for about a quarter of the ice loss from the continent.
“Pine Island and Thwaites are our biggest worry now as they are collapsing and the rest of West Antarctica will follow by almost any model,” said Isabella Velicogna, ice scientist at the University of California at Irvine. , which was not part of the study.
Although the loss of ice is part of climate change, no unusual additional warming in the region has triggered this acceleration, Joughin said.
“These scientific findings continue to highlight the vulnerability of Antarctica, a major reservoir for potential sea level rise,” said Twila Moon, a National Snow and Ice Data scientist who was not part of the research. “Time and time again, other research has confirmed that the future evolution of Antarctica will depend on human greenhouse gas emissions. “
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