Giant iceberg enters "final phase" of breaking away from Antarctica

A huge iceberg, roughly twice the size of New York City, is set to soon break off from the Brunt Ice Shelf in Antarctica. With two large cracks due to meet within the next few months, a research station has already been relocated as scientists watch the rifting event enter its "final phase."

The soon-to-be-born iceberg would measure more than 1,500 sq km (580 sq mi), and is between 150 and 250 m (492 and 820 ft) thick. Researchers have been watching the Brunt Ice Shelf carefully since 2012, when a crack that had sat dormant for 35 years suddenly showed signs of movement again. Chasm 1, as it's known, has grown steadily over the last seven years.

Then in October 2016, a second crack appeared. The "Halloween Crack," as it came to be known, was spotted to the north, running perpendicular to Chasm 1. A meeting of the two seemed likely, which would separate a large chunk of the Brunt Ice Shelf from the Antarctic mainland. In response, the Halley VI Research Station was towed about 14 miles (23 km) inland, to the other side of the cracks.

That fateful meeting finally looks set to happen within as little as two months. Interestingly enough, while it sounds like the kind of event we'd expect in a world with a changing climate, scientists aren't chalking this one up to that usual suspect.

"What many people do not realize is that this is a natural process and something which has happened time and again," says Hilmar Gudmundsson, an author of a study examining the calving event. "We recognize that climate change is a serious problem which is having an impact around the world, and particularly in the Antarctic. However, there is no indication from our research that this particular event is related to climate change."

The loss of the Brunt Ice Shelf isn't expected to contribute to sea level rise, either. Since the ice is floating on the ocean, it's already displacing the same amount of water as it will add after it melts. To back up the claim that this event is a part of the natural life cycle of the ice shelf, the team also points to historical evidence.

"Maps drawn by Shackleton and Wordie during their expedition to the Brunt Ice Shelf in 1915 show that, at that time, the ice shelf was quite extended," says Gudmundsson. "However, by the time the Halley Research Station was established in the 1950s the reach of the ice shelf was much shorter, indicating that a large iceberg must have broken away at some point after 1915."

The research is being considered for publication in the journal The Cryosphere, and the team describes the work in the video below.

Source: Northumbria University