Ice shelves 'need to calve icebergs'

The Larsen C ice shelf is a mass of floating ice formed by glaciers that have flowed down off the eastern side of the Antarctic Peninsula into the ocean.

On entering the water, their buoyant fronts lift up and join together to make a single protrusion.

The calving of bergs at the forward edge of the shelf is a very natural behaviour, says Prof Helen Fricker from the Scripps Institution of Oceanography.

She's been speaking with our science correspondent Jonathan Amos.