One of the largest icebergs ever just broke off in Antarctica

One of the largest icebergs ever recorded — measuring about the size of Delaware and containing a volume of ice twice the size of Lake Erie — has broken free from the Larsen C Ice Shelf in northwest Antarctica, according to scientists monitoring the region.

The iceberg weighs about a trillion tons, according to a team of researchers affiliated with a U.K.-based research project, known as Project MIDAS. While the iceberg calving event itself is likely mostly natural, it nevertheless threatens to speed up the already quickening pace of ice melt in the region due in large part to global warming.

The iceberg is about 2,200 square miles in area, or about the size of Delaware, Project MIDAS researchers said in a blog post on Wednesday morning. It will likely be designated “A68” by officials who track the movement of icebergs to avert shipping accidents.

“The calving of this iceberg leaves the Larsen C Ice Shelf reduced in area by more than 12 percent, and the landscape of the Antarctic Peninsula changed forever,” the researchers wrote.

Scientists have watched since 2014 as a fissure in the ice carved out a slice of the Larsen C Ice Shelf as if someone were taking a giant X-Acto Knife to the ice.

“The iceberg is one of the largest recorded and its future progress is difficult to predict,” says Adrian Luckman, a professor at Swansea University and lead investigator of the MIDAS project. “It may remain in one piece but is more likely to break into fragments. Some of the ice may remain in the area for decades, while parts of the iceberg may drift north into warmer waters.”

The iceberg itself won’t add to sea level rise, since it has already been floating in the water like an ice cube in a glass. But it may have significant consequences down the road by weakening the overall ice shelf and limiting its ability to hold back inland glaciers whose runoff does contribute to sea level rise.

The Larsen C Ice Shelf is located in the Antarctic Peninsula, which is one of the fastest-warming regions on Earth. While scientists have hesitated to pin this particular iceberg calving event to global warming specifically, the trends across parts of Antarctica, as well as the Arctic, are clear.

Ice shelves are retreating and weakening as sea and air temperatures climb, and mountain glaciers are speeding their path to the sea faster than predicted just several years ago. The result will be more significant and rapid sea level rise that will threaten the viability of coastal megacities, from Miami to Mumbai.

The Larsen C iceberg event has been one of the most closely-observed iceberg calving events in history, with data from a synthetic aperture radar aboard the European Space Agency’s (ESA) Sentinel-1 satellite providing scientists with detailed observations of the motion of the sea and land ice in that region. Other ESA satellites and NASA platforms have also aided scientists in keeping track of this iceberg.

The radar onboard the Sentinel-1 satellite is able to detect subtle changes in ground movements and is used for both studying melting glaciers and ice shelves as well as earthquakes and other geological phenomena.

Scientists affiliated with a UK-funded research project known as Project Midas kept the closest tabs on the region, with researchers from NASA and other institutions also providing their expertise.

When viewed from the air, the fissure in Larsen C stretched all the way to the horizon, and was wide enough that you’d need a plane to cross it — with sections reaching at least 1,500 feet wide.