New Map Reveals Hidden Landscape Beneath Antarctic Ice

The most comprehensive map to date of the terrain underneath Antarctica’s ice sheet has been created by an international group of researchers headed by the British Antarctic Survey (BAS).

Known as Bedmap3, it incorporates more than six decades of survey data acquired by planes, satellites, ships and even dog-drawn sleds. The results are published This week in the journal Scientific Data .

The map provides us with a distinct perspective of the white continent, imagining all 27 million cubic kilometers of ice have vanished, exposing the concealed peaks of the highest mountains and the depths of the most profound valleys beneath.

A significant update to the map involves the location identified as having the densest covering ice. Previous assessments suggested this area was within the Astrolabe Basin, situated in Adélie Land. Nevertheless, new analysis of the data indicates that it actually lies in an uncharted canyon located at coordinates 76.052°S, 118.378°E in Wilkes Land. This region boasts an impressive thickness of ice, measuring approximately 4,757 meters—over fifteen times taller than the Shard, which stands as the highest building in the UK.

Bedmap3 is poised to become a crucial resource for understanding how Antarctica will adapt to rising temperatures, as it allows researchers to examine the relationships between the ice sheet and the underlying terrain.

Dr. Hamish Pritchard, a glaciologist from BAS who led the research behind this new map, explains, “This foundational data allows us to build accurate computer simulations of how ice will move throughout Antarctica when temperatures increase. Picture honey being poured onto a craggy dessert—every bump and dip influences where the honey flows and how quickly. Similarly, in Antarctica, certain ridges can slow down moving ice, whereas valleys and flat areas may cause it to speed up.”

As its title implies, Bedmap3 marks the third endeavor since 2001 aimed at mapping the rocky terrain beneath Antarctica; however, this latest iteration showcases significant improvements. This updated version incorporates over twice as many data points (82 million) compared to before, mapped out with a resolution of 500 meters per grid cell.

Recent surveys have closed significant information gaps in various parts of East Antarctica, encompassing areas near the South Pole, along the Antarctic Peninsula, and on the western coastline as well as within the Transantarctic Mountains.

The contours of deep valleys are now depicted with greater accuracy. Similarly, areas where rugged mountains protrude above the ice are better illustrated. Recent satellite information has also enhanced the precision with which we measure the elevation and form of the ice sheet as well as the extent of the thick floating ice shelves extending into the sea from the continental edge.

The map also records a comprehensive new, continent-wide view of grounding lines—the places where ice at the edge of the continent meets the ocean and begins to float.

The landscape of the rock bed under Antarctica's ice is sensed by a variety of techniques, including radar, seismic reflection (sound waves) and gravity measurements.

Subtracting this topography from the shape and elevation of the ice above provides some fascinating statistics on the polar south.

• The total volume of Antarctic ice, encompassing ice shelves, stands at 27.17 million cubic kilometers.
• The total area encompassing the Antarctic ice, which includes ice shelves, measures 13.63 million square kilometers.
• The average thickness of Antarctic ice, encompassing ice shelves, is 1,948 meters. (Without counting ice shelves, it measures 2,148 meters.)
• Projected worldwide sea-level increase if all ice were to melt: 58 meters

Peter Fretwell, a mapping specialist and co-author from BAS, states, "Overall, it’s evident that the Antarctic Ice Sheet is thicker than initially believed and contains a greater volume of ice resting on an underlying rock bed beneath sea level. Consequently, this makes the ice more susceptible to melting as a result of the warming seawater penetrating around the edges of the continent. The new data provided by Bedmap3 reveals that our previous understanding underestimated the vulnerability of Antarctica."

More information: Hamish D. Pritchard et al, Bedmap3 updated ice bed, surface and thickness gridded datasets for Antarctica, Scientific Data (2025). DOI: 10.1038/s41597-025-04672-y

Provided by British Antarctic Survey

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