Scientific American – Deep below the bright, weather-smoothed surface of Antarctica’s ice shelves there is a dark landscape unlike any other on Earth. Fed by ice sheets on land, these giant shelves float on the frigid waters of the Southern Ocean. In their undersides melting water has carved out great inverted canyons and caves reaching up hundreds of meters, with terraces and ledges that step upward into the gloom. Sharp crevasses have been created where tidal pulls cracked the ice. And where the shelf is thickest above, ridges of ice below reach down and snag on the seabed, causing further stresses and cracks.
This month a fleet of seven underwater robots developed by the University of Washington (U.W.) in Seattle is heading into this world on a risky yearlong mission. Their goal: help forecast sea level rises by observing the melting process in this hidden topsy-turvy world, where layers of warm and cool water mix at the shelf. Because the complex physics in this unique region are poorly understood, scientists have been unable to make good predictions about the ice shelves’ future on a scale of tens of years, which is what will affect humans living near the ocean today.
“We’ve known for about 40 years that ice shelves are intrinsically unstable,” says Knut Christianson, a glaciologist on the mission and a leader of U.W.’s Future of Ice initiative. “But we don’t really understand the variability of these systems, let alone how they react to a significant external forcing like warming sea temperatures.”
Read more at Scientific American.