Many studies have focused on the melting of glaciers and ice sheets on the northern hemisphere. Satellite images and data have documented the shrinking of the northern glaciers overtime particularly Greenland’s glaciers and the disappearance of the Okjokull (Ok) glacier in Iceland. Early spring greening is also observed in Europe, Siberia, and Northern China as global temperature increases.
Now, a team of scientist have discovered that an important glacier in Antarctica is melting rapidly.
The Thwaites Glacier, located in West Antarctica, has been called the ‘doomsday’ glacier and ‘the most important glacier’ in the world according to a group of scientists from the U.S. and UK. The glacier is roughly the size of Britain or Florida and already contributes to 4 per cent of sea-level rise each year.
Why is Thwaites Glacier important?
Thwaites is very remote, even with Antarctica standards. It is located more than 1,600 kilometres from the nearest research station. It is also the stormiest part of Antarctica and so far only 4 people have been at the front of the glacier.
However, it is important for scientists to know what is happening on and below the glacier to predict future sea-level rise that is why they have come to ground zero.
The ice in Antarctica holds 90% per cent of the world’s freshwater and 80 per cent of that ice is in the Eastern part of Antarctica.
While most of the ice in the East sits on high ground, the ice on Western Antarctica where the Thwaites Glacier is, sits mostly underwater, exposed to ocean waters and vulnerable to change.
While satellites show that the glacier is rapidly retreating there has not been any on-the-ground investigation until recently when the UK and US-led research expedition came and camped on ground zero, on the ice above the point where the glacier meets the ocean water.
Part of the glacier sits on a sloping underwater ocean bed. And the glacier gets thicker as you go inland. The deepest point of the ice is more than a mile below sea level, and then another mile on top of it.
What is happening is that warm ocean water melts the glacier as it gets into contact then seeps under the ice creating a gap between the seabed and the glacier.
Nasa scientist using a ground-penetrating radar also reveals a massive cavity under the glacier. They have estimated this cavern to be two-thirds of Manhattan and 300 meters tall. This massive hole is the equivalent of 13 billion tons of ice that have melted in the past 3 years (Sample, 2019).
This massive cavity also creates ice cliffs and it will “smoosh out” says Dr Kiya Riverman, a glaciologist at the University of Oregon. Riverman says that this melting process “will just accelerate, a feedback loop, a vicious cycle”.
As melting continues so does the glacier retreats more losing its grip on the seafloor. Also, thicker parts of the glacier are becoming exposed to warm ocean waters resulting in more ice to melt and the ice shelf created is likely to break off.
To understand better what is happening on the glacier, scientists, bore a 600-meter hole through the ice and then lowered down a torpedo-shaped robot submarine called “icefin”. The device allowed scientist to see in real-time what is happening on the cavity and in the area where the warm ocean water gets into contact with the ice wall. Scientists have recorded water temperatures two degrees Celsius above freezing.
This warm water “can set the glaciers on fire and increasing melt rates by as much as a hundred-fold” says Prof Holland, an oceanographer with the New York University and one of the lead scientists of the expedition.
BBC’s video of the Thwaites Glacier:
At what pace will the Thwaites melt
Scientist says that it will take decades even more than a century for the Thwaites to vanish completely. However, this is not a reason to be complacent as a meter of sea-level rise can have a huge effect on the severity of storm surges, says Prof David Vaughan, director of science at the British Antarctic Survey.
A 50-cm sea level increase would mean storms that come every one thousand years will come every 100 years. A one-meter increase will make the millennial storm come every 10 years.
Prof Vaugh further adds that increasing carbon dioxide levels are generating heat into the atmosphere and this heat is energy, and increased energy drives the weather and big changes in the global process. Just like what is happening in the Arctic, and the Antarctic is also responding in its own way, he says.
PHOTO CREDIT: By NASA – NASA http://earthobservatory.nasa.gov/IOTD/view.php?id=2310, Public Domain, Link