The last intact section of one of Antarctica's mammoth ice shelves is weakening fast and will likely disintegrate completely in the next few years, contributing further to rising sea levels, according to a NASA study.

The research focused on a remnant of the so-called Larsen B Ice Shelf, which has existed for at least 10,000 years but partially collapsed in 2002. What is left covers about 625 square miles, about half the size of Rhode Island.