New Antarctic map offers most detailed view of subglacial terrain
An international team led by BAS has released the most detailed map of Antarctica’s subglacial terrain, revealing the continent’s thickest ice in an unnamed canyon in Wilkes Land.
A digital visualization of Antarctica’s hidden terrain, created using Bedmap3 data, showing the tallest mountains and deepest valleys beneath the continent’s ice sheet. Image credit: BAS
The thickest ice in Antarctica has been newly identified in Wilkes Land, according to the most detailed map ever created of the continent’s subglacial terrain. The map, released by an international team of scientists led by the British Antarctic Survey (BAS), challenges previous assumptions about the location of the thickest ice and provides important data on Antarctica’s ice processes.
The dataset, known as Bedmap3, integrates over six decades of geophysical surveys, capturing the continent’s tallest mountains and deepest valleys with precision. The findings present major updates on ice thickness, subglacial topography, and the continent’s response to climate change.
“This is the fundamental information that underpins the computer models we use to investigate how the ice will flow across the continent as temperatures rise. Imagine pouring syrup over a rock cake – all the lumps, all the bumps, will determine where the syrup goes and how fast. And so it is with Antarctica: some ridges will hold up the flowing ice; the hollows and smooth bits are where that ice could accelerate,” Dr. Hamish Pritchard, a glaciologist at BAS and lead author of the study, explained.
Bedmap3 builds on previous datasets by incorporating more than 82 million data points, double that of its predecessor. The high-resolution map is based on information gathered from aircraft, satellites, ships, and even historic dog-drawn sleds. Rendered on a 500 m (1 640 feet) grid, it provides an exceptionally detailed view of the land beneath Antarctica’s ice, enabling scientists to predict how ice sheets might respond to warming temperatures.
A key revision in this update is the identification of the thickest overlying ice. Earlier research placed this in the Astrolabe Basin in Adélie Land, but the latest analysis reveals the true thickest ice lies in an unnamed canyon in Wilkes Land at 76.052 °S, 118.378 °E, with a depth of 4 757 m (15 603 feet), more than 15 times the height of The Shard, the tallest skyscraper in the UK.
Data collection and improvements
Bedmap3 benefits from recent extensive surveys in East Antarctica, including regions around the South Pole, the Antarctic Peninsula, and the Transantarctic Mountains. The dataset refines the depiction of deep valleys and exposed rocky peaks while also incorporating new measurements of ice surface elevation and floating ice shelves. One of its most important contributions is the updated mapping of grounding lines, areas where the ice meets the ocean and begins to float. The data is essential for predicting how Antarctic ice might contribute to future sea-level rise.
The dataset was assembled using multiple sensing techniques like radar and seismic reflection to measure ice thickness and subglacial bed elevation, gravity measurements to detect variations in rock density beneath the ice, and satellite data to track changes in ice sheet height and surface features.
Findings and ice sheet vulnerability
“In general, it’s become clear the Antarctic Ice Sheet is thicker than we originally realized and has a larger volume of ice that is grounded on a rock bed sitting below sea-level. This puts the ice at greater risk of melting due to the incursion of warm ocean water that’s occurring at the fringes of the continent. What Bedmap3 is showing us is that we have got a slightly more vulnerable Antarctica than we previously thought,” according to Peter Fretwell, a mapping specialist and co-author at BAS.
The map reveals that the Antarctic Ice Sheet holds a total volume of 27.17 million km3 (6.5 million mi3), covering an area of 13.63 million km2 (5.3 million mi2). The mean ice thickness, including ice shelves, is 1 948 m (6 391 feet), but when excluding ice shelves, the average thickness increases to 2 148 m (7 047 feet). If all the ice in Antarctica were to melt, global sea levels could rise by 58 m (190 feet), posing a threat to coastal regions worldwide.
Scientific and environmental impacts
Bedmap3’s high-resolution dataset is expected to be a vital tool for climate scientists studying ice processes, ocean-ice interactions, and long-term changes in Antarctica’s topography. The refined grounding line mapping will aid research into the stability of ice streams and the role of subglacial features in ice flow behavior. This dataset will also contribute to studies on past climate conditions and how the Antarctic Ice Sheet evolved over millions of years.
Bedmap3 enables more accurate predictions of future ice sheet changes by providing a more precise representation of Antarctica’s subglacial landscape, helping scientists assess risks associated with ice loss and sea-level rise.
This dataset will remain fundamental for modeling the behavior of Antarctica’s ice in the face of global warming as new data continues to emerge.
Data availability
The full Bedmap3 dataset, including surface elevation, ice thickness, bed topography, and associated variations, is publicly available in multiple formats, including 16-bit signed integer Tagged Image File Format (TIFF) and Network Common Data Form (NetCDF), at a resolution of 500 m (1 640 feet).
References:
1 Bedmap3 updated ice bed, surface and thickness gridded datasets for Antarctica – Hamish D. Pritchard, Peter T. Fretwell, Alice C. Fremand, Julien A. Bodart, et.al., – nature – March 10, 2025 – https://doi.org/10.1038/s41597-025-04672-y – OPEN ACCESS
2 New map of landscape beneath Antarctica unveiled – BAS – March 13, 2025
Rishika holds a Master’s in International Studies from Stella Maris College, Chennai, India, where she earned a gold medal, and an MCA from the University of Mysore, Karnataka, India. Previously, she served as a Research Assistant at the National Institute of Advanced Studies, Indian Institute of Science, Bengaluru, India. During her tenure, she contributed as a Junior Writer for Europe Monitor on the Global Politics website and as an Assistant Editor for The World This Week. Her work has also been published in The Hindu newspaper, showing her expertise in global affairs. Rishika is also a recipient of the Women Empowerment Award at the district level in Haryana, India, in 2022.
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