Melting created an ice "canyon" in Antarctica

Icebergs calving from the Dotson Ice Shelf in 2010. Photo: Jim Yungel / NASA

Scientists have discovered a long, narrow canyon being carved under Antarctica's Dotson Ice Shelf. The upside-down feature is half as deep as the 400-meter-thick ice shelf in some places, according to new satellite observations.

Why it's happening: "Unlike most recent observations, we think that the channel under Dotson is eroded by warm water, about 1°C, as it circulates under the shelf, stirred clockwise and upward by Earth's rotation," said Noel Gourmelen from the University of Edinburgh.

Why it matters: Ice shelves hold glaciers together and slow their flow into the ocean, which can add to sea-level rise, so researchers want to better understand how canyons like these form and affect their stability.