by Scientists revealed on Tuesday that they have discovered a vast, hidden landscape of hills and valleys carved by ancient rivers that have been “frozen in time” for millions of years beneath the Antarctic ice.
This landscape, larger than Belgium, has remained undisturbed for potentially more than 34 million years, but under the influence of humans. global warming British and American researchers warned.
“It's a landscape that's been discovered – no one's eyes are on it.” Stewart Jamiesonglaciologist at Durham University, UK, and lead author Studytold AFP.
“The exciting thing is that it was hiding there in plain sight,” Jamieson added, stressing that the researchers didn't use new data, just a new approach.
The land beneath the East Antarctic Ice Sheet is less well known than the surface of Mars, Jamieson said.
The main way to “see” beneath it is by sending radio waves through the ice and analyzing the echoes, a technique called radio-echo sounding.
Communications of nature
But doing it on a continent – Antarctica is bigger than Europe – was a huge challenge.
So the researchers used existing satellite images of the surface more than two kilometers below to “probe valleys and ridges,” Jameson said.
The undulating ice surface is a “ghost image” that gently descends over this peak, he added.
When combined with radio-echo sounding data, a picture emerged of a river-carved landscape of plunging valleys and steep hills similar to some on Earth's surface today.
It was like looking out the window of a long-haul flight and seeing the mountainous region below, Jamieson said, comparing the landscape to the Snowdonia area of ​​North Wales.
The area, which stretches over 32,000 square kilometers (12,000 square miles), was once home to trees, forests, and probably animals.
But then the ice came and it was “frozen in time,” Jamison said.
Exactly when the sun last touched this hidden world is difficult to determine, but researchers are sure it was at least 14 million years ago.
Jamieson said his “prediction” is that it was last exposed more than 34 million years ago, when Antarctica first froze.
Some researchers have previously found a city-sized lake under the Antarctic ice, and the team believes there are other ancient landscapes that have yet to be discovered.
Tipping point for the “escape reaction”
The authors of the study said that global warming could threaten their newly discovered landscape.
“We are now set to develop atmospheric conditions similar to those that prevailed” 14 to 34 million years ago, when it was three to seven degrees Celsius (about seven to 13 degrees Fahrenheit) warmer than today, they wrote in the journal. Communications of nature.
Jamieson stressed that the landscape is hundreds of kilometers from the ice edge, so any possible exposure would be “remote.”
The fact that ice retreat during past warming events — such as the Pliocene period, three to 4.5 million years ago — did not expose the landscape was cause for hope, he added.
But it remains unclear what the tipping point will be for the meltdown's “unprecedented reaction,” he said.
The study was published after scientists warned that the neighboring West Antarctic Ice Sheet was melting. It is expected to accelerate substantially in the coming decadesEven if the world meets its ambitions to limit global warming.
Earlier this year, a massive chunk of the rugged Antarctic ice shelf — about two chunks the size of New York City — was released.
The Brunt Ice Shelf is located across the Weddell Sea from another ice shelf location that has made headlines, the Larsen C Ice Shelf on the Antarctic Peninsula. last year, Larsen C Ice Shelf – which was about the size of New York and was considered stable for a long time – fell into the sea.
Glacier experts have warned that some of the world's largest glaciers are It can disappear in a generation Without a drastic reduction in greenhouse gas emissions.
Traditionally, glacial ice accumulates in the winter and provides vital water for crops, transit, and millions of people during the summer on many continents as it slowly melts and feeds rivers.
“They make it very visible,” said Matthias Huss, head of GLAMOS, an organization that monitors glaciers in Switzerland and collects data for the academy's report. told CBS News last month. “People can really understand what's happening, huge glaciers are disappearing and shrinking. It's much more impressive than seeing another graph of rising temperatures.”
