A newly discovered long and craggy rift is splintering across West Antarctica’s Pine Island Glacier, satellite images show. The nearly 19-mile-long (30 kilometers) rift started in the middle of the ice shelf, where the ice shelf touches warmer ocean waters that are melting it from underneath. The rift only has about another 6 miles (10 km) to go before one or more icebergs calf, breaking off from the glacier, Lhermitte said. Another such event happened a mere year ago in 2017, when an iceberg 4.5 times the size of Manhattan broke off Pine Island Glacier.
Lhermitte found the new crack by analyzing satellite images of the glacier, which he receives every day in his email inbox. “It was Wednesday evening [Oct. 3] and all of a sudden I saw something I didn’t see the day before”.
If the iceberg breaks off in one piece, it will be a whopping 115 square miles (300 square kilometers), which is even larger than the one that broke off last year. (The 2017 iceberg was 103 square miles, or 267 square km.)
If the resulting iceberg is large enough, it will receive a name, Lhermitte noted. But, regardless of whether the crack leads to one or many icebergs, this will be the sixth large-calving event that Pine Island Glacier has experienced since 2001, he said.
The upcoming ~300km iceberg (or its disintegrated pieces) will be the next large calving event after iceberg B-44 last year and the 6th large calving of #PIG since 2018 [2/n] pic.twitter.com/LdJ2caJrhv
— Stef Lhermitte (@StefLhermitte) October 4, 2018
The upcoming iceberg isn’t loose yet, “but the fact that the rift is almost across the entire glacier, it might happen relatively soon,” Lhermitte said. It’s challenging, however, to say what “soon” means. According to Lhermitte, the calving event will likely happen in a matter of weeks or months, “but it probably won’t take years,” he said. “I expect this to happen from now to sometime this Antarctic summer.”
Pine Island Glacier is one of the fastest flowing glaciers in Antarctica. Every year, it loses 45 billion tons (40.8 billion metric tons) of ice, which in turn causes sea levels to rise 0.03 inches (1 millimeter) every eight years. Sea levels would rise 1.7 feet (0.5 m) if the entire glacier melted.
This video, which runs from 2002 to 2016, depicts just how much ice Pine Island Glacier is losing:
Granted, it’s natural for a glacier to calf icebergs. But what’s concerning about Pine Island Glacier is that it’s calving icebergs more frequently than it used to. Pine Island Glacier birthed icebergs in January 2001, November 2007, December 2011, August 2015 and September 2017. Most probably because of the volcanoes lying under the ice in this region of Antarctica. What do you think?