Discovered beneath the Antarctic ice for millions of years, a massive,
secret landscape of hills and valleys sculpted by ancient rivers was "frozen
in time" by scientists on Tuesday.
The British and American experts cautioned that although this environment,
larger than Belgium, may have been unspoiled for over 34 million years,
human-caused global warming may jeopardize its integrity.
Lead author of the research Stewart Jamieson, a glaciologist at Durham
University in the UK, told AFP that "no one has laid eyes on it."
Jamieson went on, "What's exciting is that it's been hiding there in plain
sight," stressing that the researchers had just employed a novel strategy
rather than fresh data.
According to Jamieson, the region underneath the East Antarctic Ice Sheet
is not as well-known as the surface of Mars.
Using a method known as radio-echo sounding, a plane overhead sends radio
waves into the ice and then analyzes the echoes to "see" underneath
it.
However, given that Antarctica is larger than Europe, accomplishing this
throughout the continent would be extremely difficult.
Thus, more than two kilometers (1.6 miles) below the surface, the
researchers "traced out the valleys and ridges" using already-existing
satellite pictures, according to Jamieson.
He continued, saying that the rippling ice surface is a "ghost image" that
softly falls over these sharper characteristics.
Combined with radio-echo sounding data, a picture of a river-carved terrain
resembling portions of the Earth's surface today, with steeply sided hills
and dipping valleys, became visible.
Jamieson likened the scene to the Snowdonia region of northern Wales,
saying it was like gazing out the window of a long-haul flight and seeing a
mountainous country below.
The region, which covers 32,000 square kilometers (12,000 square miles),
was formerly home to woods, trees, and maybe even some wildlife.
However, Jamieson stated that it was "frozen in time" when the ice
appeared.
It is impossible to pinpoint the exact date when sunlight last reached this
secret realm, but the researchers are certain that it was at least 14
million years ago.
According to Jamieson, his "hunch" is that it was last exposed when
Antarctica initially froze over, more than 34 million years ago.
The team thinks there may be more ancient landscapes beneath the Antarctic
ice that have not yet been uncovered, as some of them had previously
discovered a lake the size of a city.
climate risk
The study's authors suggested that their recently found environment may be
threatened by global warming.
They said in the journal Nature Communications that "we are now on course
to develop atmospheric conditions similar to those that prevailed" between
14 and 34 million years ago, when the temperature was three to seven degrees
Celsius (approximately seven to 13 degrees Fahrenheit) higher than it is
now.
Jamieson noted that any potential exposure would be "a long way off"
because the terrain is hundreds of kilometers inland from the ice's
edge.
He also said that there remained hope because melting ice during earlier
warmer occurrences, such the Pliocene epoch, three to 4.5 million years ago,
did not reveal the terrain.
However, he added, it's still unknown what might trigger a "runaway
reaction" of melting.
The report was published the day after experts issued a warning, stating
that even if global warming mitigation goals are met, the melting of the
nearby West Antarctic Ice Sheet is expected to pick up significant speed in
the upcoming decades.
