One of the largest icebergs ever recorded has broken off the West Antarctic ice shelf.

Scientists who have spent months monitoring the growing crack said on Wednesday that the anticipated “calving” on the Larsen C shelf has now taken place.

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

After monitoring a NASA Earth-observing satellite, scientists said the iceberg is thought to have remained intact at 2,200-square miles. That’s roughly four times the size of London.

Large icebergs do break off Antarctica naturally, so scientists aren’t necessarily linking the rift to manmade climate change. The area is, however, part of the Antarctic peninsula that has warmed fastest in recent decades.

Professor Adrian Luckman of Swansea University, lead investigator of the MIDAS project that has been monitoring the ice shelf for years, said that “The iceberg is one of the largest recorded and its future progress is difficult to predict. It may remain in one piece but is more likely to break into fragments.”

The iceberg was already floating before it broke away so there is no immediate impact on sea levels, but the ice could add to risks for ships in the region.