Closeup of a gigantic tabular iceberg in the Weddell sea.
Any way you look at it, we’re about to witness the birth of one massive iceberg.
Researchers with the European Space Agency (ESA) have taken more detailed measurements of the massive iceberg set to cleave off the Larsen C Ice Shelf at any minute.
According to data from instruments aboard the CryoSat and Sentinel-1 satellites, the iceberg will be one of the largest on record since at least the early 1990s, when satellite-based monitoring began in this region.
The iceberg is expected to be about 6,600 square kilometers, or about 2,500 square miles, in area. Using a radar altimeter aboard the Cryosat satellite, scientists have measured the height of the ice surface, which they used to calculate the thickness of the ice and its volume.
Noel Gourmelen from the University of Edinburgh said the iceberg is likely to be about 190 meters, or about 620 feet, thick, and contain about 1,155 cubic kilometers, or about 277 cubic miles, of ice.
On average, the soon-to-be iceberg is 620 feet thick, but at its thickest point it has a keel 689 feet below the ocean surface, and it contains about 277 cubic miles of ice.
“We have also estimated that the depth below sea level could be as much as 210 meters," which works out to be about 689 feet, he said in a statement.
This particular iceberg is likely to make world news because of its sheer dimensions, and because it will break free of an ice shelf that has been retreating in part because of global warming.
"This is a single piece which is remarkable I guess because it’s of somewhat biblical proportions,” Drinkwater said.
He said the size of this iceberg is remarkable, but the fact that an iceberg is calving from an ice shelf is not in itself unusual.
“This is a typical event in the lifetime of an ice shelf, we expect icebergs to calve,” he said. "Its pure dimensions are remarkable in some sense," he added, noting it’s one of the largest tabular (broad and flat) icebergs on record.
A comparably-sized berg drifted around the Brunt ice shelf in December 2015, the ESA said in the statement.
Iceberg tracks from 1999 to 2010.
As for where this upcoming iceberg will go once it breaks free from Larsen C, it’s not entirely clear. Drinkwater says it’s not as likely to break up into smaller pieces as past huge icebergs have done, in part because it’s remained intact as one piece while withstanding pressures from growing rifts in the ice shelf for the past several years.
“Whole or in pieces, ocean currents could drag it north, even as far as the Falkland Islands. If so it could pose a hazard for ships in Drake Passage," said Anna Hogg from the University of Leeds, in a statement.
Historical iceberg tracks suggest this iceberg will likely head northeast, potentially getting picked up by the circumpolar current and making it all the way to the South Atlantic Ocean. Along the way, it will alter natural cycles by adding cold, freshwater into the ocean and will be large enough, at least initially, to alter regional weather conditions.
The iceberg is set to break off an ice shelf located in the fastest-warming region of Antarctica, which is likely no accident. Other calving events presaged the breakup of nearby ice shelves during the past two decades, including the loss of Larsen B in 2004.
Scientists, including Drinkwater, say the broader context is that human-caused climate change is helping to eat away at floating ice shelves like Larsen C. A consequence of this is to allow ice streams on land to flow faster into the sea, thereby raising sea levels.