Antarctica\u2019s \u2018Doomsday Glacier\u2019 Is Melting Even Faster Than Scientists Thought<\/p>\n
Warming waters are reaching several miles into Antarctica\u2019s Thwaites Glacier\u2014nicknamed the \u201cdoomsday glacier\u201d because of its potential impact on sea-level rise<\/p>\n<\/div>\n
By Sachi Kitajima Mulkey<\/a> & Grist<\/a><\/p>\n At the bottom of the Earth sits a massive bowl of ice you may know as the West Antarctic ice sheet. Each day, the ocean laps away at its base, slowly eroding the glaciers that line its rim. When they inevitably give in, the sea will begin to fill the basin, claiming the ice for its own and flooding coastlines around the world.<\/p>\n Thwaites Glacier<\/a> is one of the bulwarks guarding against the collapse of this critical ice sheet<\/a>, most of which rests below sea level and holds enough ice to raise the ocean by 60 meters<\/a>, or about 195 feet. Unfortunately, this frosty Goliath, the size of Florida, is also one of the world\u2019s most unstable and fastest-melting glaciers<\/a>. While glaciologists knew its rate of ice loss was dire, they recently discovered that it\u2019s exposed to far more warming water than previously believed. In a study published last week<\/a>, scientists using satellite imagery and hydraulic modeling found that warming tidal currents are permeating the massive block of ice at depths as great as 3.7 miles, causing \u201cvigorous melting.\u201d<\/p>\n \u201cWe really, really need to understand how fast the ice is changing,\u201d said Christine Dow, an associate professor of glaciology at the University of Waterloo and one of the study\u2019s authors. \u201cWe were hoping it would take a hundred, 500 years to lose that ice.\u201d Although the researchers do not know how much faster the ice is melting, they worry it could be gone within a few decades<\/a>.<\/p>\n As climate change drives global temperatures ever higher, glaciers and ice sheets in polar and mountainous regions inevitably melt. The water and dislodged ice flows into the oceans, causing them to rise. Since 1880, global sea levels have climbed roughly 9 inches<\/a>, and any sudden increase could be catastrophic<\/a> for coastal cities<\/a> like New York, Mumbai, and Shanghai. Low-lying countries like the Marshall Islands<\/a> and Tuvalu could be submerged entirely.<\/a><\/p>\n If you’re enjoying this article, consider supporting our award-winning journalism by subscribing<\/a>. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.<\/p>\n Thwaites Glacier, often dubbed the \u201cDoomsday Glacier,<\/a>\u201d already accounts for 4 percent<\/a> of the planet\u2019s sea level rise and loses 50 billion tons of ice<\/a> annually. When it collapses, it could raise oceans worldwide by 65 centimeters<\/a>, or just over 2 feet. \u201cIt doesn\u2019t sound like a lot, but if you think of how much ocean water we have in the world, that\u2019s a huge volume,\u201d said Dow.<\/p>\n The study, published in Proceedings of the National Academy of Sciences, found that the pulsing of tides, which raise and lower the ice, allow water to creep further under its shelf and weaken its anchor to the seabed.<\/a> While the same team observed this phenomenon at Petermann Glacier in Greenland<\/a>, it had not been recorded in Antarctica. Thwaites has about eight times the amount of ice in contact with the ocean as Petermann.<\/p>\n Using high-resolution satellite images and hydrological data, the study identified high-pressure pockets where the glacier\u2019s surface had been raised, which showed that warm water was flowing under the ice. Previous models had only used the part of the glacier that touches the ocean as the \u201cgrounding line\u201d from which to start calculating the potential speed of ice loss from contact with warm, salty water. Now, according to the paper, researchers may have found the missing link in modeling how glaciers change.<\/p>\n \u201cThis boundary is a really crucial aspect in geology with respect to the glaciers\u2019 response to a changing climate,\u201d said Bernd Scheuchl, an Earth systems researcher at the University of California-Irvine and an author of the paper. He says a better understanding of the way ocean water can penetrate the base of a glacier can help scientists better predict ice loss across the West Antarctic ice sheet. \u201cThe entire region is the gateway to an area that\u2019s well below sea level.\u201d<\/p>\n Predicting the speed of ice loss and sea level rise is no easy task. Ever-shifting factors, like the amount of greenhouse gas emissions, could slow or accelerate global warming, and in turn, the rate that glaciers melt. And modeling glaciers, which are hydrologically dynamic, remote, and difficult to research, is a technological challenge that computers have only recently been able to handle, according to Dow.<\/p>\n Sharon Gray, a marine scientist at the nonprofit Rising Seas Institute, says research breakthroughs like this help the world prepare for and adapt to disappearing coastlines. \u201cIt\u2019s never going to be perfect,\u201d she said. \u201cBut obviously, the better we can get our models, the better we get our projections that help us plan.\u201d<\/p>\n Given the complexity and uncertainty of modeling, Gray said it\u2019s best to assume seas will rise to the highest predicted level and to prepare for worst-case scenarios. Some high-risk places, like Singapore<\/a> and the Netherlands<\/a>, are doing just that and have been investing in infrastructure to meet the challenge. \u201cI think there\u2019s hope and an opportunity in really thinking creatively and trying to wrap our heads around what\u2019s coming and what we can do about it,\u201d she said.<\/p>\n Researchers like Dow and Scheuchl say the best way to protect glaciers is to limit carbon emissions. Although the heat that humanity has already put into the atmosphere will linger for centuries and continue to melt glaciers, curbing the amount the planet warms could buy us time to prepare for, if not prevent, the most extreme outcomes.<\/p>\n \u201cIt\u2019s never too late to make some change,\u201d Scheuchl said. \u201cEven if we aren\u2019t able to stop these developments, we can slow things down and lessen their impacts.\u201d<\/p>\n This story was originally published by <\/i>Grist<\/i><\/a>, a nonprofit media organization covering climate, justice, and solutions.<\/i><\/p>\n<\/div>\n![\"Twaites](\"https:\/\/static.scientificamerican.com\/dam\/m\/474b998ad69c3909\/original\/thwaits_icebrige_2012_lrg.jpg?w=600\")
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