Many studies have focused on the melting of glaciers and ice sheets in the northern hemisphere. Satellite images and data have documented the shrinking of the northern glaciers over time, 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 a vital glacier in Antarctica is melting rapidly.
The Thwaites Glacier, located in West Antarctica, has been called the ‘doomsday glacier’ and ‘the most critical glacier globally.’ 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 four people have been at the front of the glacier.
However, scientists need 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 fresh water, 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 scientists 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 enormous hole is the equivalent of 13 billion tons of ice that have melted in the past three 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 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 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 scientists to see in real-time what is happening in 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. A meter of sea-level rise can considerably affect 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 ten years.
Prof Vaugh further adds that increasing carbon dioxide levels generate heat into the atmosphere, which is energy. Increased energy drives the weather and significant changes in the global process. Just like what is happening in the Arctic, the Antarctic is also responding in its way, he says.
Rowlatt, J. (2020, January 28). Antarctica melting: Climate change and the journey to the ‘doomsday glacier’. BBC Science and Environment [Article]. Retrieved from https://www.bbc.com/news/science-environment-51097309
Sample, I. (2019, December 28). Submarine to explore why Antarctic glacier is melting so quickly. The Guardian. Retrieved from https://www.theguardian.com/world/2019/dec/28/submarine-to-explore-why-antarctic-glacier-is-melting-so-quickly
Rosane, O. (2020, January 30). Record Warm Water Measured Beneath Antarctica’s ‘Doomsday’ Glacier. EcoWatch. Retrieved from https://www.ecowatch.com/antarctica-doomsday-glacier-water-2644974237.html
PHOTO CREDIT: By NASA – NASA http://earthobservatory.nasa.gov/IOTD/view.php?id=2310, Public Domain, Link