Warm Ocean Water is Melting the Doomsday Glacier

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 temperatures increase.

Now, a team of scientists 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.’ It is roughly the size of Britain or Florida and already contributes 4 per cent of the yearly sea-level rise.

Why is Thwaites Glacier important?

Thwaites is very remote, even by Antarctic 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 must 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 approximately 90% of the world’s freshwater, with 80% of that ice located in the eastern part of Antarctica.

While most of the ice in the East sits on high ground, the ice in Western Antarctica, where the Thwaites Glacier is located, is mostly underwater, exposed to ocean waters and vulnerable to change.

While satellites show that the glacier is rapidly retreating, there has been no on-the-ground investigation until recently, when a UK and US-led research expedition camped on the ground at 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 above it.

What is happening is that warm ocean water melts the glacier as it comes into contact with it and then seeps under the ice, creating a gap between the seabed and the glacier.

NASA scientists using ground-penetrating radar also revealed a massive cavity under the glacier. They have estimated this cavern to be two-thirds the size of Manhattan and 300 meters tall. This enormous hole is equivalent to 13 billion tons of ice that have melted over the past three years (Sample, 2019).

This massive cavity also creates ice cliffs, and they 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, the glacier retreats more, losing its grip on the seafloor. Additionally, the thicker parts of the glacier are becoming exposed to warm ocean waters, leading to increased ice melt, and the resulting ice shelf is likely to break off.

To better understand what was happening on the glacier, scientists drilled a 600-meter hole through the ice and then lowered a torpedo-shaped robot submarine called “icefin.”

The device enabled scientists to observe in real-time what was happening in the cavity and the area where the warm ocean water came 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 increase melt rates by as much as a hundredfold,” says Prof Holland, an oceanographer with New York University and one of the expedition’s lead scientists.

BBC’s video of the Thwaites Glacier:

At what pace will the Thwaites melt

Scientists say it will take decades, even more than a century, for the Thwaites to vanish completely. However, this is not a reason to be complacent. Professor David Vaughan, Director of Science at the British Antarctic Survey, states that a one-metre rise in sea level can significantly impact the severity of storm surges.

A 50-cm sea level increase would mean storms that come every one thousand years will come every 100 years, and a one-metre increase would make the millennial storm come every ten years.

Prof. Vaughan further adds that increasing carbon dioxide levels generate heat in the atmosphere, which is a form of 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 own way, he says.

PHOTO CREDIT: By NASA – NASA http://earthobservatory.nasa.gov/IOTD/view.php?id=2310, Public Domain, Link