Huge iceberg four times the size of Manhattan breaks off Antarctic glacier

The latest calving in Pine Island Glacier. Image credit Twitter @StefLhermitte

The latest calving in Pine Island Glacier. Image credit Twitter @StefLhermitte

An enormous Antarctic glacier has given up an iceberg over 100 square miles in size, the second time in two years it has lost such a large piece in a process that has scientists wondering if its behavior is changing for the worse.

There's something unusual going on with Pine Island Glacier.

On September 23, satellites witnessed yet another dramatic iceberg-forming event as a massive chunk of ice four times the size of Manhattan broke free.

Researchers went on to explain that smaller, thinner cracks have been spotted on the glacier, and that these may indicate that small pieces of ice could break off in the near future. This would make it the second extremely sizable iceberg to separate from the icy continent this year.

The new iceberg appears to be highly unstable, with many smaller icebergs breaking off it as it floats across the sea. It's melting differently from other parts of Antarctica. Increased retreat on the glacier may speed up its rate of ice loss, a problematic scenario that will have a notable effect on sea levels.

The current break was in the glacier's floating ice shelf, which extends out over a deep ocean cavity. "This one and 2015, they were much further inland than the previous ones".

The Pine Island Glacier is one of the largest in West Antarctica, a region that is now Antarctica's biggest ice loser. These act like cork bottles, keeping roughly 10 percent of the West Antarctic Ice Sheet from disintegrating and melting. But what's most interesting about this most recent even is not just that yet another huge iceberg has broken free, but the location from which it was calved off the larger glacier. The calving was spotted by the Delft University of Technology in the Netherlands, according to The Washington Post, which shared a satellite image (below) of the newly formed ice berg. If this continues, scientists believe that one possible result will be raised sea levels, with the entire main trunk of the Pine Island Glacier possibly breaking off in around 100 years.

"It's generally accepted that it's no longer a question of whether the West Antarctic Ice Sheet will melt, it's a question of when", said past year Ian Howat, associate professor of earth sciences at Ohio State.