Iceberg A-23a has just weeks left before complete disintegration

One of the world's oldest icebergs A-23a, is on the verge of complete disintegration and is expected to last only weeks. It detached from Antarctica's Filchner Ice Shelf 40 years ago and has come far from the icy seas, now breaking apart in warmer waters. It was once twice the size of Greater London, about 4,000 sq km.