Twenty years ago, an area of ice weighing nearly 500 billion tons was thought to have largely separated from Antarctica and separated into thousands of icebergs in the Weddell Sea.
It was the 3,250 square kilometer Larsen B ice shelf that was rapidly melting. In just a month, the 200-meter-thick giant completely disintegrated. Glaciologists were surprised by the speed and scale of the collapse. It’s simply broken. It fell like a wall and shattered like hundreds of thousands of bricks, said David Vaughan, a glaciologist with the British Antarctic Survey (BAS) in Cambridge.
Glaciologists gathered this week in New Orleans They warned that something more alarming was about to ferment In the West Antarctic Ice Sheet, a vast ice basin on the Antarctic Peninsula. Years of research by teams of British and American scientists have shown that large cracks and fissures have opened in the upper and lower Thwaites glacier, One of the largest companies in the world, and it was feared that parts of it would break and possibly collapse in five years or less.
Thwaites is located in West Antarctica and extends for 120 km of frozen coastline. A third of the glacier, along its eastern side, flows more slowly than the rest: it is supported by a floating ice shelf, An extension of the glacier is held in place by a seamount. The ice shelf acts as a clamp to prevent the faster flow of ice downstream. But The ice gang blocking Thwaites won’t last long, Erin Pettit warned, Associate Professor at Oregon State University and a member of an international team of scientists who have published new research on the future of this ice sheet.
“The Thwaites glacier makes Larsen B look small,” they say. It’s about 100 times bigger, the size of Great Britain.It contains enough water on its own to raise sea levels worldwide by more than half a metre. It contributes about 4% of the world’s annual sea level rise and has been called the most important glacier in the world, including the “doomsday” glacier. Satellite studies show that it is thawing much faster than it was in the 1990s.
While the Thwaites Glacier is concerning, there are many other large glaciers in Antarctica that are also receding, diminishing, and melting as the Southern Ocean warms. Many people are crippled because Thwaites are behaving like a cork, blocking their outlet to the sea. If Thwaites collapses, scientists believe others will accelerate, causing the entire ice sheet to collapse and a catastrophic rise in global sea level by several metres.
Whether and how quickly it could collapse are some of the biggest questions today. Sea levels are rising rapidly: the annual rate of rise is doubled with you grow 1.4 mm to 3.6 mm between 2006 and 2015 , and speed it up. A few millimeters a year doesn’t seem like a lot, but losing even a tiny fraction of Thwaites will not only help speed this up even more, but will likely increase the intensity of the storm surge.
If all the glaciers in West Antarctica collapsed, there is no coastal city in the world that would not be submerged over time at a devastating cost to life and the economy. The consensus of glaciologists was that it would take centuries of global warming before glaciers the size of Thwaites collapsed, But the loss of sea ice at the opposite end of the earth in the Arctic has been rapid and unexpected So the loss of Larsen B was surprising who – which It is now possible that this could happen quickly in Antarctica, too.
Arctic ice loss rarely affects sea level because it is formed primarily in the sea. However, Antarctic ice is mostly found on land, so any melting raises sea level. The tipping point in the Larsen B ice shelf came suddenly. How Thwaites and other glaciers will respond to global warming is still unknown, but these large global physical processes are underway and can only be addressed through global action.
but nevertheless, Just a month after Cop26 ended in Glasgow, the warning that the 300-meter-thick, 50-mile-wide Thwaites Glacier has begun to crack The silence of concerned governments on COVID-19 and the return to normal politics have been welcomed. The danger is that the many measures pledged in November to tackle global warming have been postponed for another year, becoming yet another danger in an increasingly dangerous world.
Thwaites is a sign that global warming and glaciers are not waiting for politicians, And every year, delays in taking action to reduce climate emissions accelerate global catastrophe.