Pine Island Glacier is located in West Antarctica, has shed yet another major iceberg. The calving event is not unusual for this glacier. What is new is change over the years is that calving events have changed from a multi-year process to an annual process. The bergs from Pine Island historically have broken into one single chunk of ice into an iceberg but now shatters upon separating from the glacier’s marine extension.
And here's the first hi-res @CopernicusEU #sentinel1 view of Pine Island Glacier, showing that more calving occurred in the past 24h. At least one piece is larger than 20 square nautical miles, large enough to be named by US National Ice Center. pic.twitter.com/Up8FwEVfl2— Bert Wouters (@bert_polar) February 10, 2020
The iceberg that broke from the Pine Island Glacier in western Antarctica on Saturday measures some 100 square miles. It is the second time in two years the glacier has lost such a large piece and scientists are concerned that the latest break signifies a considerable change in the behavior of the glacier.
Greenhouse gas emissions-driven global warming is being blamed for an incredible amount of ice lost each year in Antartica.
Pine Island loses an estimated 45 billion tons of ice each year to the ocean, which amounts to 1 millimeter of global sea level rise every eight years.
Last year, a study led by Seongsu Jeong and Ian Howat of Ohio State University found that Pine Island Glacier was “breaking up from the inside out.”
The researchers noted that the ice shelf had developed a new way of losing ice, rifts were forming in the center of the huge glacier rather than along its edges, suggesting the warmer waters reaching the base of the glacier is undermining it.
“Rifts usually form at the margins of an ice shelf, where the ice is thin and subject to shearing that rips it apart,” said study leader Ian Howat, associate professor of earth sciences at Ohio State. “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.”
Pine Island Ice Shelf and the Pine Island Glacier are critcal in the importance to sea level rise and the mass balance of the West Antarctic Ice Sheet.
⏲️ Tick-tock, the clock is ticking for Pine Island Glacier ⏲️— Bert Wouters (@bert_polar) February 1, 2020
Major growth of cracks spotted by @CopernicusEU Sentinel-2 satellites. New fractures showing up, others growing more than 5 km within 6 days.
Full-resolution animation ⬇️https://t.co/c3Rp8l3DMl pic.twitter.com/3UQ6LRn0WE
Knut Christianson, a glaciologist at the University of Washington in Seattle who studies Pine Island, told the Post that calving is normal and to be expected, but the “mode of calving of Pine Island Glacier appears to be shifting.”
Like Howat, Christianson suggests that calving from the interior of the glacier from warmer waters undermining the glacier’s base indicates that more frequent calving will occur.
“This results in smaller but more-frequent calving events,” he continued. “The persistence and net effect of this shift in calving behavior has yet to be determined as it has only occurred during the past two years, but it clearly merits continued observation.”
Saturday’s calving comes just 2 months after the largest ever-recorded iceberg broke from Antarctica’s Larsen C ice shelf.
This is fascinating and happening right now: a high altitude gigantic smoke cloud has been meandering for more than a week between the #Antarctica Pla and tip of S. America. Not clear the implications of it but a lot of interesting science may come out of it @m_parrington pic.twitter.com/X3rMe7BxVB— Santiago Gassó (@SanGasso) February 1, 2020
Looking down a refrozen crack in the annual sea ice of #Antarctica. You can estimate how old the crack is by how deep it is. A shallow depth means it refroze while the ice was relatively thin in early winter, a deeper crack means the ice was thicker and floating higher. pic.twitter.com/PixX2JfPjE— Anthony Powell 🇳🇿 (@Antzkiwi) November 21, 2019