In a new international rift, Larsen C, an Ice Shelf the size of Delaware, is about to leave Antarctica.
Larsen C ice is the leading edge of one of the world's largest glacier systems. A single large crack in the ice shelf has grown in spurts since 2010, lengthening to about 120 miles.
But sometime between January 1 and May 1, the crack forked in two directions. One fork continued traveling parallel to the Southern Ocean, while the other turned northward toward the water.
That 6-mile fork has increased by another 11 miles, leaving precious little ice holding back a catastrophic calving event.
"When it calves, the Larsen C ice shelf will lose more than 10% of its area to leave the ice front at its most retreated position ever recorded," Luckman and O'Leary wrote in a blog post on May 1. They say that the slab's breaking off "will fundamentally change the landscape of the Antarctic Peninsula."
The scientists' latest update came one day before President Donald Trump announced his intention to withdraw the US from the Paris Agreement on climate change.