11/15/2023 0 Comments Antarctica iceberg foundThe new smaller iceberg, A68D, is moving further away from the original. “All of those things can still happen, nothing has changed in that regard,” Tarling said. That means it could still cause an environmental disaster for local wildlife, but along the island’s eastern coast rather than the south-west. It appeared, however, to be heading south-east towards another current that would probably carry it away from the shelf edge before sweeping it back around toward the island’s eastern shelf area. They were also worried that it might block penguins making their way into the sea for food.Īs of Friday, the original A68A iceberg was about 50km (31 miles) from the island’s west coast. 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.Researchers feared that, as the iceberg closed in on the wildlife-rich island, it could grind into the seabed, disrupting underwater ecosystems. 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.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |