Let's close our eyes, just for a moment. Let's imagine a completely naked Antarctica, stripped of its 27 million cubic kilometers of ice. What would we see? Not a simple flat and uniform continent, but an intricate labyrinth of canyons, waterways and lakes: a true hidden kingdom that until now we have only been able to intuit. And yet, thanks to the project Bedmap3, this hypothetical scenario is coming into focus ever more clearly, revealing an ice-free Antarctica in never-before-seen detail.
And it is precisely this mapping that places us before a reality that is as fascinating as it is disturbing.
The last unexplored frontier
In an era in which, between sensors and satellites, we have mapped practically every square meter of the Earth's surface, there is still a "terra incognita" as large as an entire continent. Antarctica without ice is a territory that, until now, we have only been able to imagine through indirect and approximate surveys.
The new map, the result of the work of an international team of researchers, combines data from 84 new aerial surveys, adding 52 million data points and 1,9 million linear kilometers of measurements. These are not abstract numbers: this is a significant step forward in our ability to “see” through the ice.
And what we see is surprising: no longer a rough grid with 5km intervals, but a detail that reaches up to 500 meters, revealing subglacial mountains, valleys and formations that were previously simply invisible.
Ice-Free Antarctica, a Vulnerable World
What emerges from the Bedmap3 data is not just a geographical curiosity, but a worrying revelation. As explained Peter Fretwell, mapping specialist at the British Antarctic Survey and co-author of the study:
What Bedmap3 is showing us is that we have a slightly more vulnerable Antarctica than we previously thought.
I am not exaggerating when I say that this is news that should concern us all. The Antarctic ice sheet contains enough water to raise global sea levels of 58 meters if it were to melt completely. Of course, such a scenario won't happen overnight, but even small changes in the stability of the ice cap could have significant consequences.
And changes are already underway: satellite surveys show that Antarctica lost 168 billion tons of ice in 2023 (the sixth highest year on record) due to continued acceleration of glacier melt in West Antarctica and record melt from the Antarctic Peninsula.
The topography that determines the future
What makes this new map particularly valuable is its ability to reveal the detailed topography of subglacial grooves, which guide the flow of ice from the continent's interior toward the ocean. These grooves are like rivers of ice, and their shape can determine how fast the ice moves and how vulnerable it is to melting.
Hamish Pritchard, glaciologist at the British Antarctic Survey and lead author of the study, explains it with an analogy that I find particularly apt:
Imagine pouring syrup onto a rock cake: all the bumps and ridges will determine where the syrup goes and how fast. And so it is with Antarctica: some ridges will hold back the flowing ice; the troughs and smooth parts are where that ice might accelerate.
That’s the point: Knowing the shape of the land beneath the ice is crucial to predicting how the ice will flow and melt in a warming world.
The Ice-Free Antarctica We Didn't Know About
The map also reveals some surprises. For example, the thickest ice is not found, as previously thought, in the Astrolabe Basin in Adélie Land, but in an unnamed canyon in Wilkes Land, where the ice reaches the incredible thickness of 4.757 meters, more than 15 times the height of London's tallest skyscraper.
And that's not all. Many areas of Antarctica remain underexplored, especially beneath its vast ice shelves. Future missions, equipped with more advanced technology, will continue to fill in the gaps.
As I contemplate this new information published in the magazine Scientific data, I realize that what we are seeing is just the tip of the iceberg, to use an (appropriate) irony. The ice-free Antarctica is showing us a face we did not know, a territory more complex and vulnerable than we imagined. And in this new knowledge could lie the key to understanding (perhaps even mitigating) one of the greatest risks that climate change poses to our planet.
