Antarctica's Thwaites Glacier, informally known as the Doomsday Glacier for the catastrophic sea level rise its collapse could eventually trigger, is producing hundreds of iceberg earthquakes per year as its ice front fractures at a rapidly accelerating pace. Seismologists monitoring the region report that both the frequency and magnitude of these cryogenic tremors have increased markedly over the past two years, suggesting that the glacier's calving front is becoming critically unstable.
Iceberg earthquakes are produced when massive blocks of ice calve from a glacier and capsize in the ocean, releasing seismic energy detectable on instruments thousands of miles away. Their clustering at Thwaites indicates that the ice shelf holding back the glacier's flow into the sea is fracturing faster than models had predicted.
A Point of No Return
Thwaites sits on a retrograde slope — its base deepens as you travel inland — meaning that as warm Circumpolar Deep Water melts the base of the ice shelf from below, the grounding line where ice meets bedrock retreats into ever-deeper water. This creates a self-reinforcing feedback loop that is extremely difficult to reverse once started.
Scientists estimate that the full collapse of Thwaites alone could raise global sea levels by more than 60 centimeters over decades to centuries. The collapse of adjacent glaciers that Thwaites currently stabilizes could add several additional meters, threatening coastal cities and island nations worldwide.