Antarctica’s Amery Ice Shelf has produced its biggest iceberg in more than 50 years.
The calved block, dubbed D-28, covers 1,636 square kilometers (632 square miles)—about the size of urban Sydney or Scotland’s Isle of Skye.
It separated on Sept. 26 from Amery’s so-called “Loose Tooth” rift, named for its apparent likeness to a child’s wobbly dentition.
Scientists from the Australian Antarctic Program, Institute of Marine and Antarctic Studies, and Scripps Institution of Oceanography have been closely monitoring the area for nearly 20 years.
“We first noticed a rift at the front of the ice shelf in the early 2000s and predicted a large iceberg would break off between 2010 and 2015,” Scripps professor Helen Amanda Fricker said in a statement.
“I am excited to see this calving event after all these years,” she continued. “We knew it would happen eventually, but just to keep us all on our toes, it is not exactly where we expected it to be.”
Researchers have been studying the Amery Ice Shelf—the third largest in Antarctica—since the 1960s, when its last major calving event occurred.
The Amery Ice Shelf iceberg calving sequence (via ESA)
There are currently instruments deployed on the ice measuring the impact of ocean melt and ice flow.
In 2007, Australian scientists began investigating enormous cracks that, for more than a decade, formed at a rate of 10 to 15 feet a day.
Those fractures are what eventually caused the breakage of D-28—which weighs in at a whopping 688 feet thick, and carries an impressive 347 billion tons of ice.
Despite the thawing of glaciers around the world as a result of global warming, analysts believe this instance was simply the product of a natural, decades-long cycle running its course.
“We don’t think this event is linked to climate change,” according to Fricker. “It’s part of the ice shelf’s normal cycle, where we see major calving events every 60 to 70 years.”
Because the ice shelf was already floating—like an ice cube in a glass of water—the calving will not directly affect sea levels.
“But what will be interesting to see is how the loss of this ice will influence the ocean melting under the remaining ice shelf and the speed at which the ice flows off the continent,” Australian Antarctic Program glaciologist Ben Galton-Fenzi said.
Scientists will continue watching Amery closely to see how, if at all, it reacts.
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