August 23, 2024
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Antarctica’s ‘doomsday glacier’ isn’t as at risk of collapsing as we thought
Antarctica’s most dangerous glacier is wreaking havoc in slow motion, but in a rare bit of good news, the worst-case scenario of a glacier collapse may be over.
The calving front of the Thwaites Ice Shelf. The blue part is light reflected by the ice below the waterline.
The following essay is 
conversationAn online publication covering the latest research.
Thwaites Glacier in AntarcticaDoomsday GlacierIf it collapses, coastlines around the world could be flooded. Annual sea level rise of 4%As ice is lost, the glaciers will soon Collapse into the seaLike falling dominoes.
But is such a rapid collapse really as likely as feared? A new study into the vulnerability of the Swaites Glacier suggests: Instability of marine ice cliffsIt gives me hope. But Survey resultsThat doesn’t mean Thwaites is stable.
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Polar Scientist Mathieu MorlighemThe research leader explains the results.
Why is Thwaites Glacier so important?
The Thwaites Glacier drains a vast area of the Antarctic ice sheet. 74,000 square miles(192,000 square kilometers) is larger than the state of Florida. If a snowflake falls within this drainage system, it will eventually become part of an iceberg in the ocean off the coast of Swaites.
What we’re witnessing right now at Thwaites Glacier is a disaster unfolding in slow motion.
The bedrock of Thwaites Glacier lies below sea level. Going downhill inlandAs the ice sheet sinks, it deepens toward the interior of the ice sheet. Once a glacier loses more ice than it gains from new snowfall and begins to retreat, this slope makes it very difficult to slow it down. And Thwaites is already is receding at an accelerating rate As the climate warms.
Thwaites Glacier is the world’s largest glacier. Over 2 feet(0.65 meters). As Thwaites begins to become unstable, Destabilizing nearby glaciersSo what happens to the Thwaites Ice Sheet affects the entire West Antarctic Ice Sheet, which in turn affects sea level rise along coastlines everywhere.
What is marine ice cliff instability?
Marine ice cliff instability A relatively new conceptIt was proposed by scientists in the past decade.
Many of the glaciers around Antarctica Ice shelfThey support the glaciers and slow the flow of ice into the ocean. Climate change is causing some of these floating extensions to collapse, Sometimes very rapidlyWithin a few weeks to a few months.
If the Thwaites Ice Shelf collapses, it will expose very high ice cliffs along the coast. A 75-mile (120 km) frontIce can only withstand so much force, so if the cliffs are too high they will collapse into the sea.
This exposes new ice cliffs further inland, which are even higher. Marine ice cliff instability theory says that if a cliff collapses rapidly, It could cause a domino effectThe ever-higher ice cliffs collapse one after another.
But no one has ever observed marine ice cliff destabilization in action, and we don’t know if it will happen because a lot depends on how quickly the ice breaks up.
What did we find out about the risk to Thwaites?
Time Theory of marine ice cliff instabilityWhen first introduced, it used rough approximations of how ice cliffs would collapse if the ice shelf disappeared.
In subsequent studies, Ice cliffs do not collapse systematicallyThis will continue until the ice is about 442 feet (135 meters) high, and even at that point, it will break up more slowly than expected until it gets even higher.
We used three high-resolution models to explore what this new physical understanding of ice cliff instability means for Twaites Glacier this century.
Our results are If the entire Swaites ice shelf were to break up today, the instability of the marine ice cliff alone would not cause the ice front to retreat inland as quickly. Without the ice shelf, glacier ice would flow seaward much faster, thinning the glacier front and, as a result, the ice cliffs would not grow as high.
They found that the Thwaites Ice Sheet will remain relatively stable until at least 2100. They also simulated the collapse of the ice shelf 50 years from now. Glacial grounding lineWhere land-bound ice meets the sea, marine ice cliffs would have retreated far inland, but we find that marine ice cliff instability alone is not enough to cause rapid retreat.
The results call into question recent estimates of how quickly Thwaite volcano could collapse, including the worst-case scenario outlined in a report by the Intergovernmental Panel on Climate Change. Latest evaluation reportHowever, it is considered “unlikely.”
Thwaites is the glacier that everyone is worried about. When we model the whole ice sheet, this is where the marine ice cliff instability begins. Extending inlandSo if the Thwaites Glacier is not as at risk from ice cliff collapse as we thought, that’s a good sign for the whole ice sheet.
However, marine ice cliff instability is only one mechanism for ice loss, and this finding does not mean that Swaites Glacier is stable.
What else could be causing glaciers to retreat at an accelerated rate?
There are many processes that destabilize the Antarctic ice sheet, some of which are very well understood.
The interaction between ice and ocean Most of the recent ice mass lossSo far, Antarctica Very cold placeSo atmospheric warming hasn’t had a big effect yet. But warm ocean currents are getting under the ice shelf, Thinning the ice from belowThis weakens the ice shelf, which then experiences less resistance and allows the ice to flow faster.
Above Past decadesIn the Amundsen Sea sector, where the Twaites and Pine Island glaciers are located, warm water from the Antarctic Circumpolar Current enters. Melt the ice from below.
What does this have to do with climate change?
Antarctica may seem like a faraway place, Human activities that warm the planetGlobal warming, including from the burning of fossil fuels, is having a dramatic effect on the polar regions. Loss of ice contributes to rising sea levels, Impact on coastal areasAll over the world.
The choices people make today will determine how quickly the waters rise.
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