Iceberg Calving in Antarctica
An 18-mile-long crack, 400 feet deep, has formed in the Antarctic ice, NASA reports. It's part of a process called calving, in which a huge piece of ice breaks off a glacier and forms an iceberg. This one will be 340 square miles (880 square kilometers) of surface area, The Christian Science Monitor reports. The ice shelf in this region is about 1,640 feet, or 500 meters, thick, with all but 160 feet of the ice shelf underwater.
"We are actually now witnessing how it happens, and it's very exciting for us," IceBridge project scientist Michael Studinger of NASA's Goddard Space Flight Center in Greenbelt, Md., told Our Amazing Planet.com, in The Christian Science Monitor. "It's part of a natural process, but it’s pretty exciting to be here and actually observe it while it happens."
It happens when the glacial ice is pulled westward along the Hudson Mountains in Antarctica toward the Amundsen Sea, The Christian Science Monitor story said. An offshoot of ice stretching 30 miles into the Amundsen, and as the ice pushes toward the sea, that spit of ice snaps off, unleashing an iceberg. This iceberg-forming rift is opening up by 6.5 feet, or two meters, daily, Agence France Presse reported.
The birth process is not all that uncommon, but it's rare to witness it, scientists said, and the October 14 sighting by NASA surveillance planes afforded some unique insights.
It does not mean that new ice is forming, and indeed, when the new iceberg has floated away, the leading edge of the ice shelf that it breaks off of will be the farthest back that it has been since the 1940s, when the shelf was first measured.
Ice melt is a concern everywhere, and not limited to the Antarctic. Although Canada's ice is not known as an iceberg incubator per se, it is melting rapidly, and at the end of September an alarm was sounded.
Canada's Arctic region has lost nearly half its ice shelf extent in the past six years. One major ice shelf, the Serson, disappeared almost completely, and the Ward Hunt shelf split in half, CBC News reported, for an ice loss of three billion tonnes (metric tons), or 500 times the mass of the Great Pyramid of Giza.
“This is our coastline changing,” says Derek Mueller, from Carleton University’s department of geography and environmental studies, told CBC News. “These unique and massive geographical features that we consider to be a part of the map of Canada are disappearing and they won’t come back.”
These shelves took thousands of years to form, he added.
More information on melting ice caps is at Our Amazing Planet.