Iceberg the size of Greater London set to break off from Antarctica
NASA satellite images show two cracks running across the Antarctic Brunt Ice Shelf which could break off and create a 1,700 km-iceberg.
The rift, known as the 'Halloween crack' first appeared in October 2016, and is spreading to the east. It is set to meet another fissure that had been stable for 35 years but is now accelerating north at a rate of 2.5 miles a year.
Once that happens, the shelf will release an iceberg measuring approximately 660 square miles (1,700 square km), larger than all of London's boroughs combined (607 miles squared) and twice the size of New York. This is likely to happen in a matter of weeks and it will be the biggest iceberg to separate from the Brunt Ice Shelf since 1915.
Depending on where the cracks merge, the stability of the entire shelf could be jeopardised, Joe MacGregor, a glaciologist at NASA's Goddard Space Flight Centre told Earth Observatory: "If the [cracks] merge upstream (south) of the McDonald Ice Rumples, then it's possible that the ice shelf will be destabilised."
The long-term future of Antarctic ice shelves will have an important influence on sea level rise around the globe. A report released by scientists last year stated that Antarctic ice is melting at a record-breaking rate, accelerating threefold in the last five years, and now poses a major threat to coastal cities.
Unless there are major reductions greenhouse gas emissions, scientists say that Antarctica's melting ice should add more than 25cm to total global sea level rise by 2070.
