Antarctica's Ice Is Melting in Ways We Never Expected
A robot submarine named Ran mapped the underside of Antarctica's Dotson Ice Shelf and discovered that the ice is melting in complex, uneven patterns driven by warm ocean currents. These findings, published in Science Advances, reveal that ice shelves are wearing away faster in some areas than others, weakening their ability to hold back land-based glaciers that raise global sea levels.
What did the submarine Ran find under the Dotson Ice Shelf?
In 2022, researchers with the International Thwaites Glacier Collaboration sent an autonomous underwater vehicle named Ran beneath West Antarctica's Dotson Ice Shelf. The bright orange robot, roughly 20 feet long, used upward-looking sonar to sweep 54 square miles of the shelf's hidden underside.
What came back surprised everyone. The ice was not the smooth sheet scientists expected. Instead, Ran's maps revealed terraced formations like frozen staircases, deep channels, scooped grooves, and teardrop-shaped pits gouging upward into the ice, some stretching nearly 1,000 feet long.
Anna Wåhlin, the oceanographer from the University of Gothenburg who led the research, said the experience felt like getting a first look at the far side of the Moon. None of these formations had ever appeared on satellite imagery, making Ran's data entirely new to science.
Why does uneven melting matter for coastal communities?
Ice shelves like Dotson function as doorstops, holding back the massive glaciers that sit on land behind them. When a shelf thins, it loses its grip, and those land-based glaciers start sliding into the ocean. That is where the real danger lies, because land-based ice is what raises sea levels.
You might assume an ice shelf melts evenly, the way an ice cube dissolves in a warm drink. Ran's maps proved otherwise. The western side of Dotson melts faster because ocean currents run stronger there, pushing more heat into the ice. The eastern side remains calmer. This uneven wear means some sections of the shelf are weakening faster than models predicted.
Since 1979, Antarctic melt has already pushed global sea levels up by about half an inch. For coastal communities in the United States and around the world, that translates to higher tides, worse flooding, and more damage from storms. The more precisely scientists can map and predict this melting, the better cities can prepare.
How do ocean currents carve strange shapes into ice?
The strange formations Ran documented are directly tied to the behavior of a current called Circumpolar Deep Water. This relatively warm, salty water drifts up from the Southern Ocean and reaches the underside of the ice shelf, quietly wearing it down.
The word