An iceberg the size of Delaware is poised to break away from Antarctica, an event which may lead to the collapse of a massive ice shelf on the continent, according to researchers.
Scientists say that a 1,900 square-mile section of the "Larsen C" ice shelf is now only connected to the main body by a 12-mile section of ice. Researchers monitoring a huge crack in the ice discovered that it had grown rapidly during the second half of 2016 — increasing in size by 11 miles in December alone.
If the iceberg does break away, it would be one of the ten largest ever recorded.
When the iceberg breaks off, or calves, the shelf will lose around 10 percent of its surface area, leaving it at its most-retreated ever recorded position, according to researchers at Project MIDAS, a British-backed Antarctic research project.
"If it doesn't go in the next few months, I'll be amazed," project leader Professor Adrian Luckman, from the U.K.'s Swansea University told the BBC. Researchers had previously suggested that a calving event could take place at some stage in the next decade.
Scientists say that calving events like this one could lead the Larsen C ice shelf to disintegrate entirely, as its neighbor Larsen B did in 2002.
"We think that once this iceberg has gone, the Larsen C ice shelf will be in a less stable position than before, precisely how much less stable depends on what path the crack takes as it propagates," Martin O'Leary, a researcher on the project, told NBC News. "I think we're probably more worried that the next iceberg could cause the next iceberg to collapse rather than this time around," he added.
In November 2016, NASA scientists carrying out an airborne survey of polar ice measured the crack in Larsen C to be about 70 miles long, more than 300 feet wide and about a third of a mile deep.
Scientists have been monitoring the rift on the ice shelf for decades. Researchers told NBC News that the calving event was "part of the natural evolution of the ice shelf," but added there could be a link to changing climate, though they had no direct evidence of it.
|© An oblique view of a massive rift in the Antarctic Peninsula's Larsen C ice shelf, Antarctica, on No... Image: Antarctic iceberg expected to break away|
Iceberg the size of Delaware to break off from Antarctica
A large sheet of ice is set to break away from Antarctica and scientists say it will be one of the largest breaks of its kind recorded.
Larsen C -- a sprawling sheet of ice in western Antarctica -- is currently attached to its parent shelf by 20 kilometers (12.4 miles) of ice, according to UK-based research team Project MIDAS.
Once it splits, the crack will produce an iceberg around 5,000 square kilometers (1,930 square miles) -- approximately the size of the state of Delaware.
In August, researchers at MIDAS reported that a crack in Larsen C grew 22 kilometers (13.7 miles) in six months' time. In December the rift accelerated -- clocking an additional 18 kilometers (11 miles) of further movement through colder glacial ice within a month.
Although this isn't the first time the Antarctic has seen icebergs produced in this way, Larsen C's split will significantly change the landscape of the continent.
"When it calves, the Larsen C Ice Shelf will lose more than 10% of its area to leave the ice front at its most retreated position ever recorded; this event will fundamentally change the landscape of the Antarctic Peninsula," lead researcher Professor Adrian Luckman said in a statement posted to the MIDAS website.
Martin O'Leary, a researcher at MIDAS, told CNN the huge iceberg could render the remaining sheet of ice unstable -- causing sea levels to rise and to overall changes to the Antarctic's landscape.
"I think in terms of the impact that the iceberg has on the ocean, it's a very spectacular event but its not going to be a huge thing in itself -- the iceberg is big but the oceans are a lot bigger," O'Leary added.
In 2002, Larsen C's neighboring ice shelf, Larsen B, violently broke off from its parent, shattering into millions of pieces -- accelerating a mass of broken ice into the Antarctic current.
Before Larsen B collapsed, it demonstrated a pattern similar to Larsen C. In 1995, another ice shelf, Larsen A, also broke off from the same ice mass.
Since then, researchers at MIDAS have been tracking Larsen C with a close eye.
O'Leary said that Larsen A and B's breaks were "unequivocally climate change-related," but so far researchers aren't linking global warming to Larsen C's split.
The team says the break in Larsen C has likely been caused by natural geographic patterns marked in their research for decades.
"We don't think there is a strong link to change climate change in terms of the provocation of the crack in question ... but we couldn't work that out," O'Leary said.
Giant iceberg set to break off of Antarctica
A giant iceberg larger than Rhode Island is set to break off of Antarctica, British scientists announced Friday. If it occurs, it would be one of the biggest icebergs on record.
Scientists have been keeping a close eye on a crack in an Antarctica ice shelf that could break off, creating an iceberg and indirectly lead to rising sea levels.
The crack grew by 11 miles in December. Only a final 12 miles of ice now connects the iceberg to its parent ice shelf, according to Project MIDAS, a British Antarctic research project.
The crack in the Larsen C Ice Shelf is more than 1,000 feet wide and has grown by 50 miles since 2011, according to the British Antarctic Survey. Once the crack goes all the way across, the iceberg will break off.
"If it doesn't go in the next few months, I'll be amazed," project leader Adrian Luckman of Swansea University told BBC News. It would be among the top 10 biggest icebergs ever recorded.
"There’s no need for alarm," however, according to a tweet from Project Midas. "This is a fairly normal event, although it is spectacular and quite rare," the tweet said.
Global warming may have caused the likely separation of the iceberg but the scientists say they have no direct evidence to support this, the BBC said.
Ice shelves are permanent floating sheets of ice that connect to a landmass, according to the National Snow and Ice Data Center.
Most of the world's ice shelves hug the coast of Antarctica. The Larsen C shelf is on the Antarctic Peninsula, the portion of the continent that juts out toward South America.
If the iceberg did break off, it wouldn't contribute to sea-level rise since it's already floating, said Ted Scambos, a scientist with the data center. If a chunk of ice that big did drop into the sea, it would raise sea levels about one-sixteenth of an inch, he said.
However, once that iceberg breaks off, land ice that had been blocked by the berg would plop into the sea. It's that ice that would raise sea levels, NASA scientist Thomas P. Wagner said.
"Ice shelves serve a critical role in buttressing ice that's on land," he said.
Once the iceberg sheared off, it would float along the coast of Antarctica, then head out into the Southern Ocean.
"As it moved north, ocean temperatures both at the surface and at the base of the berg would begin to thin it and erode it from the edges," Scambos said. It would eventually break apart into smaller chunks that would melt into the ocean.