An iceberg twice the size of New York City is set to break away from Antarctica.
According to the National Aeronautics and Space Administration (NASA), cracks growing across Antarctica’s Brunt Ice Shelf are poised to release the iceberg and it is not yet clear the effect this will have on the remaining ice shelf.
NASA has been tracking the cracks through satellite images and an image from January 1986 compared to one from just a few weeks ago shows just how much the crack has extended.
NASA reports say that one crack, called the Halloween crack, first appeared in late October 2016 and it continues to grow eastward from an area known as the McDonald Ice Rumples.
But the more immediate concern is the rift visible in the center of the satellite images.
While previously stable for about 35 years, NASA says this second crack has started accelerating northward as fast as four kilometres per year.
When the cracks intersect, the iceberg that is likely to release from the shelf will likely be at least 1700 square kilometres.
While there have been plenty of reports of much larger icebergs by Antarctic standards, this may be the largest berg to break from the Brunt Ice Shelf since observations began in 1915.
Scientists are watching to see if the loss will trigger the shelf to further change and possibly become unstable or break up.
The Brunt Ice Shelf in 1986. Source: Nasa
The Brunt Ice Shelf in 2019. Source: Nasa
NASA reports that calving is a normal part of the life cycle of ice shelves, but the recent changes are unfamiliar in this area.
The edge of the Brunt Ice Shelf has evolved slowly since Ernest Shackleton surveyed the coast in 1915, but it has been speeding up in the past several years.
