Giant Iceberg on Antarctic Continent Expected to Collapse

The main reason is the Antarctic Circumpolar Current (ACC), the only current that flows completely around the globe and contains more water than any other current on Earth. 

The ACC that runs west to east through the Drake Passage transports between 3,400 to 5,300 million cubic feet (95 and 150 million cubic meters) of water every second, according to Britannica.