Why London, New York and Shanghai should be worried about Antarctica’s ‘doomsday glacier’

On the shores of Kiribati seawater laps at homes on stilts, washing away crops and fresh groundwater. 

No part of this island state rises more than two metres above the Pacific Ocean. Two atolls have already disappeared under the waves and scientists predict the area could be uninhabitable within the next few decades, displacing hundreds of thousands of people. 

It is a picture threatened worldwide – from Venice to the Netherlands, the Maldives to London – and now scientists fear the accelerated melting of Antarctica’s “doomsday glacier” could bring it on more rapidly.

For the first time, evidence has emerged that warm sea water is getting beneath the colossal Thwaites Glacier, driving increases in sea levels globally. 

“The worry is that we are underestimating the speed that the glacier is changing, which would be devastating for coastal communities around the world,” said Dr Christine Dow, a professor in the Faculty of Environment at the University of Waterloo and co-author of the study. “Thwaites is the most unstable place in the Antarctic.”

As climate change pushes global temperatures higher and higher, glaciers and ice sheets in mountainous regions and polar ice caps are melting. The eroding ice flows straight into the world’s oceans, pushing up sea levels. 

Global sea levels have climbed by around nine inches since 1880. Any sudden increase could be catastrophic for coastal cities, like London, New York and Shanghai. 

The Thwaites glacier rivals the state of Florida in size and holds enough water to raise the ocean by 65 centimetres, or just over 2 feet. The icy mass already accounts for 4 per cent of the planet’s sea level rise and loses 50 billion tons of ice annually. 

Thwaites, which measures about 120 kilometres wide by 1.2 kilometres deep, has been melting slowly for decades. Now a team of international researchers have discovered evidence of more “vigorous melting”. 

Satellite observations show water running beneath its base, exposing it to far more warm water than previously believed.

“In the glacier, there are these bullseye features, which show that water is getting in and filling a pond underneath the ice at that point, filling and emptying,” explained Dr Rob Larter of the British Antarctic Survey who has studied the Thwaites Glacier extensively. 

“The water will be travelling along a sort of subglacial channel, where it’s in contact with the ice because that water has two or three degrees above the temperature at which the ice would melt.” 

‘We probably have reached the point of no return’

The creeping water caused by the push and pull of tides sneaks under Thwaite’s shelf to weaken its anchor to the sea bed. 

Although the same team noted this phenomenon at Petermann Glacier in Greenland, it had not been recorded in Antarctica

Thwaites is also considerably bigger than Petermann, with around eight times the amount of ice in contact with the ocean.

The study’s authors hoped that it would take hundreds of years for Thwaites to lose its ice, but now fear it could be a matter of decades.

Dr Larter said the study represents a “missing link” in explaining what is happening “beneath many hundreds of metres of ice”.

The team used the high-resolution satellite images and hydrological data to pinpoint high-pressure pockets where the glacier’s surface had risen.

Dr Larter said examining polar ice to predict rising sea levels is an arduous task. 

Usually, scientists drill deep holes or use submersible technology to go deep into the ocean and far under the ice to monitor change. 

“It’s very difficult work because this is one of the most inaccessible environments on the planet. You’re talking about trying to work out what’s going on beneath many hundreds of metres of ice,” he said. 

Scientists believe vulnerable nations should invest in protecting themselves from the rising sea levels, as London has done with the Thames Barrier. 

Longer term, they says the best way forward is to limit carbon emissions.

But for the doomsday glacier it may already be too late.

“It’s probably too late to stop the retreat of overall arctic ice”, said Dr Larter. “We probably have reached the point of no return.”

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