Lambert Glacier Deep Dive
The Lambert is the longest glacier on Earth: around 400 km of mainstream flow from the East Antarctic interior to the floating Amery Ice Shelf in Prydz Bay. Together with its tributaries it drains roughly 16% of East Antarctica. Yet it is barely known to the public, because almost no one ever sees it.
Geography
The Lambert system originates around the Gamburtsev Subglacial Mountains, an entirely buried mountain range under several kilometres of ice, and flows north through one of the deepest subglacial troughs on the continent — over 2,500 m below sea level in places. The trunk is up to 80 km wide.
The Amery Ice Shelf
The Lambert ends in the Amery, the third-largest ice shelf in Antarctica (after the Ross and Filchner-Ronne). Amery has produced several huge calving events in recent decades; iceberg D-28 (about 1,600 km²) calved in September 2019.
Mass balance
Most studies show the Lambert-Amery system as approximately balanced or with a slight positive accumulation, in contrast to West Antarctica's accelerating losses. This is one reason the East Antarctic ice sheet has been considered relatively stable. Recent satellite data, however, suggests that some Lambert tributaries have begun to thin.
Discovery and naming
The glacier was identified from Australian aerial photographs in 1952 and named for Bruce Lambert, an Australian surveyor-general. Subsequent ground traverses through the 1950s and 60s mapped its geometry; modern dimensions come almost entirely from satellite remote sensing.
Speed
Surface speeds along the main trunk reach about 1,200 m per year near the grounding line — slow compared to West Antarctica's fast- flowing rivers of ice, but spread over an enormous width.
Access
There is essentially no public access. The Australian Mawson and Davis stations sit relatively near, and Australian science traverses use the Lambert region for fieldwork, but tourist expeditions do not reach it. Some sub-Antarctic cruises pass within sight of the Amery cliffs.
Why it matters
East Antarctica holds enough ice to raise sea level by about 53 metres. The Lambert-Amery system is the largest single drainage of that volume. Forecasts of long-term sea-level rise depend on whether this system stays stable, and current data are still unfolding.
Keep exploring
The interactive map shows the Lambert and Amery, the recent calving footprints, the Mawson and Davis stations, and the locations from which sub-Antarctic cruises can occasionally see the front.