Meltwater Is Lubricating Antarctica's Glaciers — Directly Measured at the Ice Bed

Antarctica holds 90 percent of the world's glacier ice. If it melted completely, sea levels would climb roughly 60 meters. For years, climate models have tracked how much ice is leaving the continent, but the exact reason the ice is speeding up toward the ocean has been partly guesswork. Now, for the first time, the mechanism has been watched directly from below.

Professor Shin Sugiyama of Hokkaido University and colleagues drilled boreholes more than 550 meters into the Langhovde Glacier in East Antarctica. Using a hot-water jet to carve the hole, they lowered pressure sensors and a camera to the glacier bed — a place satellites, flying overhead, can never see.

What the sensors found

Water pooling in lakes and ponds on the glacier surface was traveling all the way down. The route opened through a process called hydrofracturing: the weight of accumulated meltwater forces cracks deeper into the ice, creating channels through which the water descends. Once it reaches the bedrock, it does something decisive — it lifts the glacier.

During intense surface-melting spells, and after a rare rainfall in January 2022, the water pressure at the base built up enough to support 97 percent of the glacier's own weight. The ice rose slightly. With less friction holding it back against the rock, the glacier's sliding motion accelerated by 10 to 20 percent.

Why this matters

This lubrication effect has long been documented in Greenland, Alaska, and European glaciers. But Antarctica's ice is far thicker and, in many places, anchored to the ocean floor by a single glacier tongue — the classic "tipping point" geometry that makes it especially sensitive to change. Confirming that meltwater can reach the base in East Antarctica means a key part of the ice-loss equation is now measured, not assumed. As the climate warms and surface melting becomes more common, those hidden boreholes suggest a faster slide than the models may yet be capturing.