A chunk of ice so large it will be visible from space is poised to break off from an Antarctic ice shelf, British scientists have found.

A crack in the Larsen C ice shelf in the Antarctic Peninsula grew by 17 kilometres between May 25 and May 31 and is now about 193 km long. There are only 13 km left until the crack cuts right across the shelf. The resulting iceberg will be significantly bigger than Prince Edward Island.

The process is known as calving.

According to NASA: “Ice shelves are the floating parts of ice streams and glaciers, and they buttress the grounded ice behind them; when ice shelves collapse, the ice behind accelerates toward the ocean, where it then adds to sea level rise.”

Scientists at Swansea and Aberystwyth universities in Wales are closely watching the state of the ice to determine whether climate change is playing a role. They say the rift – about 300 metres wide – is the largest jump since January and predict a full break is coming soon.

“When it calves, the Larsen C Ice Shelf will lose more than 10 per cent of its area to leave the ice front at its most retreated position ever recorded; this event will fundamentally change the landscape of the Antarctic Peninsula,” scientists wrote on their Project MIDAS blog.

The group says the rift will destabilize the ice shelf and it may follow the example of its smaller neighbour Larsen B, which disintegrated in 2002 following a similar calving. The ice shelf itself floats on water but is fed by the flow of ice glaciers that sit above sea level. Scientists fear the disappearing Larsen C will only speed up glacier flow toward the sea and raise global sea levels.

Larsen C, at nearly the size of Scotland, is the fourth largest ice shelf in Antarctica.

University of Colorado scientist Ted Scambos says the shelf appears to be breaking further back than previously recorded calvings. Scambos adds that “this berg is telling us something has changed, and not for the better. For now, though, the ice shelf will barely notice.”

With files from The Associated Press

Larsen C ice shelf rift development (graphic by Nick Kirmse / CTVNews.ca)

Graphic by Nick Kirmse / CTVNews.ca