NASA image by Jesse Allen and Robert Simmon

A piece of ice four times the size of the island of Manhattan has broken off from Greenland’s Petermann Glacier in what may be the largest glacier collapse in recorded history.

A similarly sized piece of ice broke off the Petermann in 1962. This latest collapse reduces the glacier’s ice shelf by about 25%.

According to a BBC News report the ice could disrupt shipping lanes between Greenland and Canada or freeze in place.

From an National Geographic article:

The so-called “ice island” covers a hundred square miles (260 square kilometers) and holds enough water to keep U.S. public tap water flowing for 120 days, according to Andreas Muenchow, a physical ocean scientist and engineer at the University of Delaware.

Though glacier collapses are an expected and regular occurrence, one of this magnitude is a surprise.

Professor Muenchow is quoted in an article in the Telegraph regarding whether the cause of the ice breaking off was global warming. He said it was difficult to determine because records of seawater around the glacier have only been kept since 2003:

Nobody can claim this was caused by global warming. On the other hand nobody can claim that it wasn’t.

–Andreas Muenchow, University of Delaware

Additional resources:

Washington Post – Massive chunk of ice breaks off Greenland glacier