Antarctica’s frozen edges may look solid, but they are more unstable than you think. Beneath those thick ice shelves, ocean currents are at play, warming hidden cavities and slowly reshaping the West Antarctic Ice Sheet. Scientists are now exploring these areas using advanced underwater robots, revealing secrets that were once out of reach.
In a groundbreaking mission under the Dotson Ice Shelf, researchers deployed a robot named Ran. This autonomous vehicle mapped an area never before surveyed in such detail. It traveled over 1,000 kilometers in just 27 days, gathering high-resolution sonar images of sub-ice terrain.
While the mission was a success, the robot eventually lost contact. Before that happened, it discovered unexpected structures beneath the ice, such as jagged ledges and teardrop-shaped pits, shaped by warm water. Anna Wåhlin, a professor of oceanography at the University of Gothenburg, described the findings as akin to “seeing the back of the Moon for the first time.”
These insights showed that melting isn’t uniform across the Dotson Ice Shelf. Instead, it’s concentrated in specific areas. Two large cavities were found to be connected by narrow channels, allowing warm water to flow in efficiently. This uneven melting supports prior findings from climate models and satellite data.
Studies indicate that the Dotson Ice Shelf has lost nearly 390 gigatonnes of ice in the last two decades. As the ice thins, it becomes less able to hold back the glaciers behind it. Notably, researchers observed that long-standing fractures have begun to widen due to turbulence, potentially allowing more warm water in and accelerating hidden ice loss.
In early 2024, scientists returned to Dotson to continue their exploration. However, during a follow-up dive, Ran vanished without a trace. Experts speculate it might have faced mechanical failure or collided with an underwater ridge. Despite this setback, the sonar data already collected is crucial for understanding ice-ocean interactions. The incident has also reignited discussions on the durability of autonomous systems in extreme environments.
So, what does this all mean for global sea levels? Ice shelves like Dotson act as barriers for large glacier systems. When they weaken, glaciers can flow more rapidly into the ocean, contributing to rising sea levels. Estimates suggest that melting under Dotson has added about 0.02 inches to sea level rise between 1979 and 2017. Meanwhile, the total ice loss from West Antarctica has exceeded 0.5 inches, with the rate of melting increasing.
Data from Ran shows that melting is not a slow, steady process; warm water targets specific features, leading to faster degradation than many models account for. As scientists continue their work, understanding these patterns of melting will be vital for predicting future changes in sea levels.
