An iceberg the size of Singapore detached from Antarctica’s Pine Island Glacier earlier this month, according to a report and images released by NASA. Scientists have hypothesized that rapidly-changing ice sheets are a result of warming weather.
“It is hard to predict with certainty where and when these things will drift,” said NASA glaciologist Kelly Brunt. According to the BBC, UK researchers have been awarded a £50,000 emergency grant to track the iceberg, which could threaten international shipping lanes.
NASA scientists have been studying the Pine Island Glacier closely because of evidence that warmer seawater is causing the ice “grounding line,” the point at which a glacier is attached to the coastal bedrock, to recede.
Scientists have stated that warming water is melting the undersides of Antarctic ice shelves. When the ice shelves that surround the perimeter of the ice sheet are weakened, the pressure from the shelves that normally helps hold the ice sheet decreases, allowing the ice sheet to flow faster.
According to NASA scientists, “Faster flow = smaller ice sheet = higher sea levels = slow motion coastal flooding worldwide.”
The Pine Island Glacier shelf has been moving forward at roughly 4 kilometers, or about 2.49 miles, per year, so the iceberg, which has been named B-31, is not necessarily a surprise, according to Tom Wagner, NASA’s cryosphere program manager. These events happen about every 5 to 6 years. The difference is that Iceberg B-31 is about 50 percent larger than previous bergs in the area.
Scientists first noticed a crack spreading across the surface of the Pine Island Glacier in October 2011 via satellite imagery. Researchers will now use satellites to track the movement of B-31 and attempt to predict its possible future courses.
Before any drifting can occur, B-31 has to exit Pine Island Bay and enter the Southern Ocean. “Where it is going depends on the deeper currents into which its keel extends, “said NASA scientist emeritus Robert Bindschadler, who likened an iceberg’s movement to the movement of a stick in a mountain stream.
“If you ever throw a stick into a mountain stream, you would see an erratic flow as it spins, accelerates, and decelerates,” Bindschadler said. “I imagine a similarly variable current field working on the iceberg’s keel.”