![]() REUTERS/Alister Doyle/File Photo Alister Doyle/Reuters It was because of that research that scientists began calling the region around the Thwaites the “weak underbelly of the West Antarctic ice sheet.”Ī 20 metre-high ice cliff forming the edge of the Wilkins Ice shelf on the Antarctic Peninsula is seen from a plane January 18, 2009. Nearly a decade later, they found that – because the glacier is grounded to a seabed, rather than to dry land – warm ocean currents could melt the glacier from underneath, causing it to destabilize from below. As early as 1973, researchers questioned whether it was at high risk of collapse. The Thwaites Glacier itself has concerned scientists for decades. ![]() But it’s just a faction of the West Antarctic ice sheet, which holds enough ice to raise sea level by up to 16 feet, according to NASA.Īs the climate crisis has accelerated, this region has been closely monitored because of its rapid melting and its capacity for widespread coastal destruction. The Thwaites Glacier, located in West Antarctica, is one of the widest on Earth and is larger than the state of Florida. Palmer working near the Thwaites Eastern Ice Shelf in in 2019. The scientists hope to figure this out by drilling through the ice to sample rock of the landmass underneath it, which could show if the current rate of melt is reversible, or if the glaciers have truly passed a point of no return.The US Antarctic Program research vessel Nathaniel B. The researchers' findings, while alarming, don't address how many times the glaciers may have retreated and readvanced across recorded history. What this means for the future of Antarctica's glaciers and ice sheet - and vulnerable coastlines around the globe - is unclear. "Although these vulnerable glaciers were relatively stable during the past few millennia, their current rate of retreat is accelerating and already raising global sea levels," Rood said. But over the past three decades, the rate of shoreline advance has skyrocketed - up to 1.6 inches (40 mm) per year. From that moment in time until about 30 years ago, ice loss exposed the shorelines at a rate of about 0.14 inches (3.5 millimeters) each year, the researchers reported. The half-life of carbon-14 (or the time it takes for half of it to decay) is 5,730 years, and scientists can pinpoint the ages of animals that died thousands of years ago by measuring quantities of undecayed carbon-14 in the remains.Īfter dating penguin bones and shells from more than 20 different shorelines, the scientists found that the oldest and highest beach began to form roughly 5,500 years ago. When animals die, they stop accumulating carbon-14 in their tissues and the amount that they've already absorbed begins to decay. This method identifies the age of organic material by measuring the amount of carbon-14, a radioactive carbon isotope, or variant with a different number of neutrons, which is found everywhere on Earth and is easily absorbed by plants and animals. The researchers estimated the ages of the shorelines by collecting ancient shells and tiny fragments of penguin bones, before analyzing the ancient biomatter with radiocarbon dating. The reality of climate change: 10 myths busted Antarctica: The ice-covered bottom of the world (photos) By measuring the ages and heights of nearly two dozen shorelines, the scientists hoped to discover how quickly ice disappeared from the land before advancing again. Ice weighs down land, so as some of that frozen weight melted and drained into the sea toward the end of the last ice age (around 11,500 years ago) the land rebounded to reveal shorelines that were previously hidden beneath the waves. ![]() To compare the glaciers' melt rates today with those of the distant past, scientists looked for clues on Antarctic beaches close to where the glaciers terminated at the ocean. If the entirety of the West Antarctic Ice Sheet were to break up and melt into the sea, it would elevate global sea levels by approximately 11 feet (3.4 meters). Additionally, this melt from below weakens the glaciers and makes them more prone to surface fractures, which could spread across the entire ice sheet, and potentially cause it to shatter. This warm water isn't just melting the glaciers where they extend into the Amundsen Sea, but it is also whittling away at them from underneath, unpinning them from their main anchoring points located to the north. As the sea-facing ends of the glaciers are positioned above a bowl-like ocean basin, both glaciers are exposed on their undersides to currents of warm, dense, salty water. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |