"Denman Glacier is retreating into the deepest undersea valley in all of Antarctica. Nearly 5 feet of sea level rise are at stake."
"Scientists have found a new point of major vulnerability in the Antarctic ice sheet, in a region that already appears to be changing as the climate warms and has the potential to raise sea levels by nearly five feet over the long term.
Denman glacier, in East Antarctica, is a 12-mile-wide stream of ice that flows over the deepest undersea canyon in the entire ice sheet before spilling out into the ocean. That subsea trough is more than 2 miles deep, or double the average depth of the Grand Canyon. While there are far deeper trenches in the open ocean, such as the Marianas Trench, in this case the extreme undersea topography lies right on the outer fringe of the Antarctic continent — making it the “deepest continental point on Earth.”
That deep canyon is a potential pathway for the ocean to infiltrate deep into Antarctica’s center — posing a threat of significant sea level rise."