4 Meters: The Sea Level Risk of the Wilkes Subglacial Basin
Melting ice within the Wilkes Subglacial Basin in East Antarctica could drive global sea levels up by three to four metres, according to a scientific study. The remote geographic depression spans 1,400 kilometres by 400 kilometres, with large portions resting significantly below sea level.
More than a century ago, Australian geologist Sir Douglas Mawson led a sledge expedition covering hundreds of kilometers of ice into this isolated sector of East Antarctica before turning back following the death of a team member. A subsequent party led by fellow Australian Cecil Madigan similarly penetrated the area before retreating. Modern researchers note that neither historical mission, nor any subsequent documented party, has set foot on this ice sheet.
Ocean Temperatures Threaten Subglacial Stability
While the surface of the Wilkes Basin presents a uniform expanse of ice, the underlying bedrock drops as deep as 2,000 meters below sea level. The ice sheet currently maintains sufficient thickness to block the ocean from penetrating directly into the interior basin, but surrounding waters remain in constant contact with its edges.
Waters off the coast of East Antarctica hover at approximately -1.8 degrees Celsius. Even a slight temperature increase driven by oceanic warming or shifting currents could accelerate melting along the basin’s perimeter, forcing ice to discharge rapidly into the sea. Because portions of the underlying bedrock slope downward toward the interior away from the ocean, any initial retreat risks becoming self-sustaining as warming water reaches deeper ice reserves.
Historical Precedent From the Pliocene Epoch
Reconstructions of past warm periods indicate that regional ice sheets shrank dramatically when global temperatures were 2 to 3 degrees Celsius warmer than today. During the Pliocene epoch roughly three million years ago, global temperatures matched that elevated range relative to pre-industrial levels, causing ice sheets to retreat hundreds of kilometers inland and driving global sea levels between 6 and 23 meters higher.
Earth is currently on a trajectory to reach comparable warming levels by the end of the century. Projections indicate this warming will accelerate melt rates and trigger a pronounced retreat across the Wilkes Subglacial Basin.
Data Gaps Hinder Knowledge of Wilkes Basin
Current knowledge of the Wilkes Basin relies heavily on airborne radar surveys capable of penetrating thick ice to map the sub-surface topography. Satellite observations from the 1970s and 1980s documented the collapse of a fringing ice shelf along the East Antarctic coastline, marking the first known event of its kind in the region.
Despite these observations, critical information remains absent. Researchers lack comprehensive bathymetric maps detailing the pathways through which warm ocean water reaches the ice, alongside consistent long-term records of regional ocean temperatures. Without these variables, predicting the precise timeline of future ice loss remains difficult.
While neighboring regions like the Thwaites Glacier have been subject to extensive international research programs for years, the Wilkes Subglacial Basin continues to conceal the specific oceanic mechanisms driving its vulnerability.