A massive iceberg with enough freshwater in it to fill Sydney Harbour 135 times over is about to break off the Mertz glacier in Antarctica.
The iceberg will be 75 kilometres long and contains 750,000 gigalitres of ice.Scientists are not sure if it is a natural event or if global warming is to blame. But a joint Australian and French team hope to find out.The Mertz Glacier is near Commonwealth Bay in East Antarctica.It flows into the southern ocean for 140 kilometres before it drops icebergs into the sea.
A large crack has formed about half way along the Mertz Glacier, which means it is going to drop a very large iceberg.
French glaciologist Benoit Legresy is measuring the break-up.