Why scientists are worried about Antarctica’s ‘Doomsday Glacier’: How dangerous could disintegration of ‘Great Britain-sized’ ice shelf be for Earth and humanity?
According to LiveScience, the immediate concern is the possible collapse of the glacier’s floating eastern ice shelf; This is a development that could accelerate ice loss in Antarctica and contribute to rising global sea levels in the coming decades and centuries.
What is Doomsday Glacier?
Thwaites Glacier is the largest glacier in the world, spanning an area approximately the size of Great Britain. Located off the coast of West Antarctica, the region plays a crucial role in retaining much of the West Antarctic Ice Sheet.
Scientists have nicknamed it the “Doomsday Glacier” because of the enormous amount of ice it contains and the possible consequences if it becomes unstable.
For more than four decades, warm ocean water has been melting the glaciers from below. Thwaites has retreated more than 20 kilometers (about 12 miles) since the early 1990s, according to investigators.
Why is the eastern ice shelf so important?
The biggest concern is not the glacier itself, but the floating eastern ice sheet. The shelf acts as a natural barrier, slowing the movement of ice from land to the Southern Ocean. If this protective layer breaks down, the glacier can begin to flow into the sea much more quickly.
Warmer ocean water drifting beneath the ice shelf is causing large cracks to spread, according to the International Thwaites Glacier Collaboration. Satellite observations show that the shelf is rapidly weakening and approaching a critical breaking point.
Will sea levels rise immediately?
According to Live Science, the collapse of a floating ice shelf alone would not cause a sudden rise in sea levels because the shelf is already floating in the ocean. The real danger comes after this.
If the ice sheet does not act as a brake, Thwaites Glacier could accelerate and release the increased amount of ice on land into the sea. Over time, this additional ice will directly contribute to global sea level rise.
Scientists estimate that global sea levels could rise by about 65 centimeters (2.1 feet) if the Thwaites Glacier eventually disappeared.
What do scientists say?
According to a report by New Scientist, recent satellite images show that the eastern ice shelf is close to separating from the main glacier.
Researchers say the shelf is cracking where it remains attached to a ledge on the seafloor, while sections of ice are breaking away at nearly twice the rate observed last year.
Glaciologist Robert Larter of the British Antarctic Survey and the International Thwaites Glacier Collaboration told New Scientist:
“The last ice sheet in front of the glacier is getting ready to break apart. We don’t know exactly how it will break, but it will definitely disappear.”
Why is Thwaites Glacier melting?
Scientists believe that changing ocean conditions associated with climate change are leading to warmer, saltier waters beneath the glacier’s ice sheet.
Changing wind patterns across the Southern Hemisphere are helping to push deep ocean water beneath floating ice, according to New Scientist.
Larter explained: “There is debate about the details, but there is little doubt that human-induced climate change is a big part of what we are seeing.”
What happens if the glacier eventually collapses?
Scientists emphasize that it will take a very long time (possibly decades, even centuries) for the Thwaites Glacier to completely collapse.
But if the glacier eventually becomes unstable, it could trigger further collapse of neighboring glaciers on the West Antarctic Ice Sheet.
In a worst-case scenario, this chain reaction could eventually contribute more than 3.3 meters (more than 10 feet) to global sea levels and significantly reshape coastlines around the world.
Researchers continue to refine their models, but a recent study suggests Thwaites could lose as much as 200 billion tonnes of ice each year by 2067.
Which countries may be affected?
While Antarctica may seem distant, the consequences of continued ice loss will be felt worldwide.
Low-lying countries such as Bangladesh, the Maldives and many Pacific island nations will face increased flooding, coastal erosion and saltwater intrusion into freshwater supplies.
Major coastal cities such as Miami, New York, Shanghai, Jakarta and Mumbai may face more frequent flooding and stronger storm waves, while even countries with advanced flood defenses such as the Netherlands may face increasing challenges.
Scientists say there is still uncertainty
Researchers emphasize that significant uncertainties remain.
Even if the eastern ice shelf breaks up soon, the Thwaites Glacier is not expected to collapse completely immediately. Scientists continue to study how the glacier and the West Antarctic Ice Sheet will respond in the coming years.
However, experts agree that each new crack and each rise in ocean temperatures is another reminder of how closely linked Earth’s climate systems are and how changes in Antarctica could ultimately affect millions of people living thousands of kilometers away.
Inputs from TOI
