Live Science reported in April that the Thwaites Glacier, or the "Doomsday Glacier," was discovered to be melting faster than previously thought. But not all parts of West Antarctica have been quite so lucky. The Ronne Ice Shelf, which birthed the recent iceberg, is mostly spared from influxes of warm water that disrupt the Antarctic's natural cycle of ice calving and regrowth. The rogue berg shattered into a dozen pieces before it caused any harm, Live Science previously reported. After splitting from the Antarctic ice sheet in 2017, A-68A was set loose by ocean currents in 2020 and came perilously close to colliding with South Georgia Island, a breeding ground for seals and penguins. Satellites will continue to track the new iceberg, much as they did for A-68A, the previous title holder for the world's largest iceberg. "It's important to monitor the frequency of all iceberg calving, but these are all expected for now." Thwaites underlines that global heating and glaciers do not wait for politicians, and every year action to reduce climate emissions is delayed only accelerates global disaster."A76 and A74 are both just part of natural cycles on ice shelves that hadn't calved anything big for decades," Laura Gerrish, a researcher at the British Antarctic Survey, wrote on Twitter. ![]() The danger is that the many actions pledged in November to address global heating will be shelved for another year, to become just one more risk in an increasingly dangerous world. Yet just one month after Cop26 ended in Glasgow, the warning that the 300-metre thick, 50-mile wide Thwaites glacier has started to crack up has been met with silence from governments preoccupied by Covid-19 and the return of normal politics. How Thwaites and other glaciers respond to global heating is still not known but these big global physical processes are under way and can be addressed only by global action. The tipping point for the Larsen B ice shelf came suddenly. Antarctic ice, however, is mostly on land so any melting adds to sea levels. Ice loss in the Arctic barely affects sea levels because it mostly forms at sea. The consensus of glaciologists used to be that it would take centuries of global heating before glaciers the size of Thwaites shattered and collapsed, but so rapid and unexpected has been the loss of sea ice at the opposite end of the earth in the Arctic, and so sudden was the loss of Larsen B that it is now considered possible it could happen rapidly in Antarctica, too. Should all West Antarctica’s glaciers ever collapse, there is no coastal city in the world that would not, over time, be swamped at ruinous cost to life and economies. A few millimetres a year does not sound much but the loss of even a small part of Thwaites would not just help to speed this up further but would likely increase the severity of storm surges. Sea levels are rising fast: the annual rate of increase more than doubling from 1.4mm to 3.6mm between 20, and accelerating. Whether and how quickly they may collapse are some of the most important questions of the age. Should Thwaites fall apart, scientists believe the others would speed up, leading to the collapse of the whole ice sheet and catastrophic global sea level rises of several metres. ![]() Many are being held back because Thwaites acts like a cork, blocking their exit to the sea. Thwaites is worrisome, but there are many other great glaciers in Antarctica also retreating, thinning and melting as the Southern Ocean warms. Satellite studies show it is melting far faster than it did in the 1990s. It contributes about 4% of annual global sea level rise and has been called the most important glacier in the world, even the “doomsday” glacier. It is roughly 100 times larger, about the size of Britain, and contains enough water on its own to raise sea levels worldwide by more than half a metre. Thwaites makes Larsen B look like an icicle. Years of research by teams of British and American researchers showed that great cracks and fissures had opened up both on top of and underneath the Thwaites glacier, one of the biggest in the world, and it was feared that parts of it, too, may fracture and collapse possibly within five years or less. This week, ice scientists meeting in New Orleans warned that something even more alarming was brewing on the West Antarctic ice sheet – a vast basin of ice on the Antarctic peninsula. It fell over like a wall and has broken as if into hundreds of thousands of bricks”, said one. Glaciologists were shocked as much by the speed as by the scale of the collapse.
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