Scientists uncover Antarctica’s hidden landscape under ice sheet for first time

Until now, the surface of Mars was better mapped than the subglacial terrain of Antarctica

Scientists have unveiled the most comprehensive map yet of the hidden landscape beneath Antarctica's colossal ice sheet, revealing a vibrant topography of mountains, canyons, valleys, and plains, alongside tens of thousands of previously undetected hills and smaller formations.

This groundbreaking research, published in the journal Science, utilised cutting-edge high-resolution satellite observations and a technique known as ice-flow perturbation analysis. This method infers subglacial terrain and conditions from surface features, enabling the mapping of the entire continent, including previously unexplored regions.

A more precise understanding of this subglacial bedrock is vital for predicting the climate-driven retreat of Antarctica's ice sheet. Earlier studies have shown that rugged terrain, such as jagged hillsides and mountain peaks, can impede this retreat.

Robert Bingham, a glaciologist from the University of Edinburgh in Scotland and a lead author of the study, emphasised the map's importance: "Having the most accurate map of Antarctica's bed shape is crucial, because the shape of the bed is an important control on friction acting against ice flow, which in turn we need to include in numerical models that are used to project how rapidly Antarctica's ice will flow towards the ocean, melt and contribute to global sea-level rise."

The researchers were able to map the subglacial terrain with unprecedented precision. For instance, they identified more than 30,000 previously uncharted hills, defined as terrain protuberances of at least 165 feet (50 meters).

The Antarctic Ice Sheet is the largest mass of ice on Earth. (Getty Images)

Antarctica is about 40% larger than Europe, 50% larger than the United States and roughly half the area of Africa.

"In every case, all of these continents contain an array of very different landscapes in themselves, from towering mountain ranges to immense flat plains. The hidden landscape of Antarctica also contains these vast extremes," Bingham said. "Boring it is not."

The Antarctic Ice Sheet is the largest mass of ice on Earth and holds about 70% of the planet's freshwater. Its average thickness is estimated at about 1.3 miles (2.1 km), with a maximum thickness of about 3 miles (4.8 km).

Antarctica has not always been covered in ice. Its subglacial features initially were sculpted before the continent acquired its icy covering more than 34 million years ago before being further modified by the dynamic ice sheet. Antarctica once was connected to South America but separated due to a process called plate tectonics involving the gradual movement of continent-sized plates on the Earth's surface.

The map revealed a landscape bearing various topographical features."Possibly the type of landscape that many people might know less is 'plateaus dissected by deep-carved glacier valleys.' I can tell you this is very familiar for Scots, but also a landscape that is common across Scandinavia, northern Canada and Greenland. In fact, the very fact that the landscape our technique has uncovered across Antarctica matches these landscapes so well gives us great confidence in our new map," Bingham said.

The researchers noted that until now the surface of Mars was better mapped than the subglacial terrain of Antarctica.

The researchers hope the map will help inform models used to project future sea-level rise. (Getty Images)

Traditionally, scientists have mapped the subglacial landscape using radar equipment suspended on planes or towed by snowmobiles, according to glaciologist Helen Ockenden of the Institut des Geosciences de l'Environnement in France, lead author of the study.

"But these surveys often have gaps of 5 km (3.1 miles) or 10 km (6.2 miles) between them, and sometimes up to 150 km (93 miles)," Ockenden said.The method used in the new study, Ockenden said, "is really exciting because it allows us to combine the mathematics of how the ice flows with high-resolution satellite observations of the ice surface, and say what the landscape beneath the ice must look like everywhere across the whole continent, including in all those survey gaps. So we really gain a much more complete idea of how all the landscape features connect together."

The researchers hope the map will help inform models used to project future sea-level rise as well as the forecasts issued by the IPCC, the U.N. Intergovernmental Panel on Climate Change that provides governments with data to shape climate-related policies.

"We can now also identify better where Antarctica needs more detailed field survey, and where it does not," Bingham added.