In Antarctica, however, it’s the land ice that really counts. Their study finds that melting of the West Antarctic ice sheet caused a sea-level rise of more than three metres and it took less than 2C of … Lett. A new scientific study found Antarctica is melting six times faster than 40 years ago. Using radar information collected between 1992 and 1996, oceanographer Eric Rignot, based at NASA’s Jet Propulsion Laboratory, found that the Pine Island Glacier’s “grounding line” — the line between the glacier’s floating section and the part of the glacier that rests on the sea floor — had retreated rapidly towards the land. He said he thought the ice forced the colony to be abandoned, but also suggested that warming temperatures might change things in the years ahead. The latest data reveals that Antarctica is losing ice at an accelerating rate, too. Melting of Antarctic Ice Is Accelerating, Study Shows UN Climate Change News, 18 June 2018 - Antarctica’s ice sheet is melting more rapidly than previously expected, a scientific study published in the scientific research journal Nature has revealed, adding to the sense of urgency to act on climate change and to finalize the implementation guidelines of the Paris Agreement at the end of … Daniel Bailey, Thirty-two years ago, glaciologist John H. Mercer of the Institute of Polar Studies sounded a fire alarm about global warming. Ice shelves are the part of a glacier that extends past the grounding line towards the ocean; they are the most vulnerable to warming seas. “If we lose the summer ice, it makes a big difference,” says Ron Kwok. Most ice sheets, particularly those located in the inner parts of the continent, were generally stable from 1999 to 2019. 36, L17501 (2009). However, in this case, I really don't have a feeling for the size of the Antarctic ice cap. Res.Lett. Antarctic sea ice is ice which forms in salt water mostly during winter months. But he was clear about what the ‘warning signs’ would be. Mayewski, et.al., "State of the Antarctic and Southern Ocean Climate System," Rev. Antarctica’s ice is melting fast. Other evidence that the amount of sea ice around Antarctica seems to be increasing slightly2-4 is being used in the same way. Ten ice shelves along the Antarctic Peninsula have disintegrated since the 1970s, including two spectacular collapses last decade. Randal Jackson The fact that it’s above linear, this is the important idea, that ice loss is increasing with time,” she says. Compared to the Arctic, Antarctic sea ice shows less variability in summer, and more variability in winter. “It isn’t just one type of measurement. They behave very differently. It is predicted that the melting conditions of the Antarctic ice sheet surface will continue to increase, especially in West Antarctica and Antarctic Peninsula. Michael Schodlok, a JPL scientist who models the way ice shelves and the ocean interact, says melting of the underside of the shelf is a pre-requisite to these collapses. If all of this ice melted, it would raise global sea level by about 60 meters (197 feet). Since the early 1990s, European and Canadian satellites have been collecting radar data from West Antarctica. There has been lots of talk lately about Antarctica and whether or not the continent’s giant ice sheet is melting. Free-floating sea ice gets blown around by the wind, while glaciers move downhill, driven by gravity. the ice that sticks around even at the height of the Arctic summer) is such a big reflector of the summer sun. The most recent estimate of land ice change that combines estimates from these three approaches reported (IMBIE, 2017) that between 1992 and 2017, the Antarctic Ice Sheets overall lost 2,720 giga-tonnes (Gt) or 2,720,000,000,000 tonnes into the oce… Melting all the sea ice on Earth would have no direct effect on sea level, while melting all the land ice would have a huge impact on sea level. West Antarctica’s glaciers are in rapid retreat. Overall, not much is going on in East Antarctica — yet. 36, L19503 (2009). If we want to understand how the ocean is impacting the ice sheet, go to where it’s hitting the ice sheet with a sledgehammer, not with a little tack hammer.”, Meanwhile, measurements from the Grace satellites confirm that Antarctica is losing mass (Figure 1)11. The frozen continent of Antarctica contains the vast majority of all freshwater on Earth. 7P.A. Its impact on the sea level rise will become significant. ‘Teetering at the edge’: Scientists warn of rapid melting of Antarctica’s ‘Doomsday glacier’ Thwaites glacier is losing ice at an accelerating rate, threatening catastrophic sea-level rise Lett. “Once we lose the summer ice cover permanently, will we tip the planet into a new climate state?”. JPL scientist Ron Kwok saw it as demonstrating that “the old idea that glaciers move really slowly isn’t true any more.” One result was that a lot more people started to use the radar data to examine much more of Antarctica. “The important message is that it is not a linear trend. Because it’s a group of islands, much of the West Antarctic Ice Sheet (WAIS, in jargon) is actually sitting on the floor of the Southern Ocean, not on dry land. Copyright © 2020 CGTN. Rignot’s paper surprised many people. Over the 1999-2019 period, more than 2.63 million square kilometers of the Antarctic ice sheet surface had experienced observable melting, which is nearly one-fifth of the total area, said the MOST 2020 annual report of remote sensing monitoring on the global ecological environment. ... Go back to the melting ice in a glass of water. About 19 percent of the surface of the Antarctic ice sheet had experienced melting during the past two decades, according to a report released Friday by the Chinese Ministry of Science and Technology (MOST). The study demonstrates, for the first time, that during this period, changes in the Antarctic ice sheet were driven by the melting ice sheets in the Northern Hemisphere. Holly Shaftel The study looked at 176 different basins around Antarctica where ice drains into the ocean and found that the rate of melting is increasing, … The answer boils down to the fact that ice can flow without melting. He attributed the retreat to the warming waters around West Antarctica6. Susan Callery Larger Image The Antarctic ice sheet. 11Isabella Velicogna, "Increasing rates of ice mass loss from the Greenland and Antarctic ice sheets revealed by GRACE," Geophys. There is a continent about the size of Australia underneath all this ice; the ice sheet sitting on top averages at a little over 2 kilometers (1.2 miles) thick. But the loss of land ice in Antarctica threatens to raise global sea level, sparking scientists’ interest in the southernmost continent. He’s leading an expedition scheduled to start in 2011 to drill through the Pine Island Glacier and place an automated buoy into the water below it. Sea ice waxes and wanes with the seasons, but minimum and maximum extents rarely match from year to year; over years and decades, summer and winter extents vary. In the "the longest-ever assessment" of Antarctica 's ice mass, scientists are reporting a rapid increase in melting — a six-fold increase in yearly Antarctic ice … Lett. Science Editor: West Antarctica is very different. 6 E.J. Two-thirds of Antarctica is a high, cold desert. Pine Island is the largest of these islands and the largest ice stream in West Antarctica is called Pine Island Glacier. Antarctic sea ice had been gradually increasing during 40 years of measurement and reached a record maximum in 2014, before falling markedly. Res. The retreat of West Antarctica’s glaciers is being accelerated by ice shelf collapse. Credits: NASA's Operation IceBridge Map showing the rates of mass changes from ICESat 2003-2008 over Antarctica. An international team of researchers led by geoscientist Dr Kim Jakob from Heidelberg University has now examined the dynamics of the East Antarctic Ice Sheet more closely. As temperatures rise due to climate change, the melting of polar ice sheets is accelerating. It extends from the far north in the winter and retreats to almost the coastline every summer, getting closer and closer to the coastline every year due to sea ice melting. One new paper 1, which states there has been less surface melting recently than in past years, has been cited as “proof” that there’s no global warming. Melting glaciers (land ice) contribute to sea level rise; melting sea ice does not. Measuring changes in Antarctic land ice mass has been a difficult process due to the ice sheet's massive size and complexity. Last summer, a British group revisited the Pine Island Glacier finding and found that its rate of retreat had quadrupled between 1995 and 20068. Mercer’s warning signs are already appearing, despite the reality that human activities haven’t yet raised atmospheric carbon dioxide levels to twice the pre-industrial average. The eastern half is the big player in this game: it holds 10 times more ice than the West — enough, on its own, to raise sea levels by 170 feet. It’s a series of independent measurements that are giving the same results, which makes it more robust.”. One new paper1, which states there has been less surface melting recently than in past years, has been cited as “proof” that there’s no global warming. 2 http://arctic.atmos.uiuc.edu/cryosphere/ IMAGES/ current.anom.south.jpg, 3http://www.sciencedaily.com/releases/ 2009/ 04/090421101629.htm, 4http://nsidc.org/seaice/characteristics/ difference.html. Her work shows that the ice sheet is not only losing mass, but it is losing mass at an accelerating rate. Still, areas of the continent, like the Antarctic Peninsula photographed above, have increased their mass loss in the last decades. A lot of attention has been devoted to sea ice in the Arctic over the last few years, where ice cover has clearly shrunk and thinned since the beginning of the satellite data record in 197813. How is it possible for surface melting to decrease, but for the continent to lose mass anyway? Antarctica’s Larsen C Ice Shelf experienced its highest rate of melting since records began 40 years ago from 2019-2020, a new study has … Gravity data collected from space using NASA’s Grace satellite show that Antarctica has been losing more than a hundred cubic kilometers (24 cubic miles) of ice each year since 2002. Thinning of the ice shelf reduces its buttressing effect on the glacier behind it, allowing glacier flow to speed up. In the prestigious journal Nature he wrote, “I contend that a major disaster — a rapid 5 meter (16 foot) rise in sea level, caused by deglaciation of West Antarctica — may be imminent or in progress after atmospheric CO2 [carbon dioxide] content has only doubled.” He forecast visible changes only decades in the future, ensuring little policy-level, let alone public, interest. 36, L15501 (2009). A new paper explores what will happen to the southernmost continent if we curb carbon emissions — or do nothing. Science Editor: Parts of it are more than 1.7 kilometers (1 mile) below sea level. Geosci. The oceans surrounding Antarctica have been warming10, so Schodlok doesn’t doubt that the ice shelves are being undermined by warmer water being brought up from the depths. During the period, around 19 percent of Antarctica's area experienced melting. This website is produced by the Earth Science Communications Team at, Site Editor: This subject analyzes the temporal and spatial variation characteristics of the Antarctic ice sheet surface melting, ice shelf disintegration, and penguin habitat distribution and their correlations, said Wang Qi'an, director of the National Remote Sensing Center of China. 8 D. J. Wingham et.al., "Spatial and Temporal Evolution of Pine Island Glacier thinning, 1995-2006," Geophys. These radar data can reveal ice motion and, by the late 1990s, there was enough data for scientists to measure the annual motion of the Pine Island Glacier. Melting was mostly distributed on the edge of the Antarctic ice sheet and the Antarctic Peninsula, with an increasing trend. 9 E. Rignot et.al., "Accelerated ice discharge from the Antarctic Peninsula following the collapse of Larsen B ice shelf," Geophys. 10R. However, since the 1990s the problem has been attacked from multiple directions via multiple methods. East Antarctica is much higher in elevation than West Antarctica. Radar- and laser-based satellite data show a little mass loss at the edges of East Antarctica, which is being partly offset by accumulation of snow in the interior, although a very recent result from the NASA/German Aerospace Center’s Gravity Recovery and Climate Experiment (Grace) suggests that since 2006 there has been more ice loss from East Antarctica than previously thought5. Over the 1999-2019 period, more than 2.63 million square kilometers of the Antarctic ice sheet surface had experienced observable melting, which is nearly one-fifth of the total area, said the MOST 2020 annual report of remote sensing … Some of the ice at the Antarctic extends as much as 2 kilometers (1.2 miles) deep underwater. Antarctic sea ice is the sea ice of the Southern Ocean. The small plane takes us to the camp in the middle of the West Antarctic Ice Sheet but more bad weather means more delays and it is nine days before a Hercules comes to take us back to McMurdo. Previously, Antarctic sea ice extent had been above that long-term average due to long-term, large-scale wind circulation patterns that drove sea ice away from Antarctica 5, making room for more sea ice to form nearer to the continent. An international team of researchers led by geoscientist Dr Kim Jakob from Heidelberg University has now examined the dynamics of the East Antarctic Ice Sheet more closely. Managing Editor: These changes largely result from the geographic differences mentioned above, namely Antarctic sea ice’s distance from the pole (se… 31, L18401 (2004). How the ice shelf crumbles The Antarctic as a whole contains about 90 percent of the planet’s ice — enough in theory to raise global sea levels an average of roughly 200 feet should it all melt. M. Robertson et al., “Long term temperature trends in the deep waters of the Weddell Sea”, Deep Sea Research 49, 21, 4791-4806 (2002); http://condor.pems.adfa.edu.au/FD-Course/webpage/longterm.pdf. Historian, NASA/Jet Propulsion Laboratory. West Antarctica has warmed by more than 0.1 °C/decade in the last 50 years, and this warming is strongest in winter and spring. I'm not sure about the area or the depth of ice. 12 J. H. Mercer, "West Antarctic ice Sheet and CO2 Greenhouse Effect-Threat of Disaster," Nature 271 (5643), 321-325 (1978). Rignot, "Fast Recession of a West Antarctic Glacier, Science 281, 549-551 (1998). In the summer, meltwater ponds on the surface can drain into the cracks. The newly independent iceberg is one of the largest ever recorded. But he admits that it hasn’t been proven rigorously, because satellites can’t measure underneath the ice. Known as East Antarctica, this section has an average altitude of about 2 kilometer (1.2 miles), higher than the American Colorad… It is of high scientific value for further research on the stability of the Antarctic ice sheet and global climate change, Wang added. Larger Image Two-thirds of Antarctica is a high, cold desert. 6 Climate models, or computer simulations that incorporate all the factors that affect Earth’s climate, predicted this behavior. Rothrock, "Decline in Arctic sea ice thickness from submarine and ICESat records: 1958 - 2008," Geophys. Lett. Isabella Velicogna of JPL and the University of California, Irvine, uses Grace data to weigh the Antarctic ice sheet from space. Sea ice is frozen seawater that is usually less than a few meters thick. As temperatures rise due to climate change, the melting of polar ice sheets is accelerating. Res. But little, if any, surface warming is occurring over East Antarctica. Meanwhile, in rapidly-melting parts of West Antarctica, “upside down rivers” of warm water are gnawing away at the ice shelves’ weak spots from below, according to a … Although this is partly offset by fall cooling in East Antarctica, this effect is restricted to the 1980s and 1990s. 36, L18502 (2009). A longstanding theory in glaciology is that these ice shelves tend to buttress (support the end wall of) glaciers, with their mass slowing the ice movement towards the sea. And the Pine Island Glacier would contribute about 10 percent of that. According to a 2009 study, the continent-wide average surface temperature trend of Antarctica is positive and significant at >0.05 °C/decade since 1957. That meant that the glacier was losing mass. Climate scientists are interested in Arctic sea ice decline because permanent sea ice (i.e. A linear trend means you have the same mass loss every year. East Antarctica is much higher in elevation than West Antarctica. And she points out that it isn’t just the Grace data that show accelerating loss; the radar data does, too. 47, 1-38 (2009). The net, total behavior of all ice in the Antarctic is causing a significant and accelerating rise in sea level. Since liquid water is denser than solid ice, enough meltwater on the surface can open the cracks up deeper down into the ice, leading to disintegration of the shelf. Geophys. Glaciologist Robert Bindschadler of NASA’s Goddard Space Flight Center intends to show just that. Most ice sheets, particularly those located in the inner parts of the continent, were generally stable from 1999 to 2019. Res. Antarctic ice sheets could be at greater risk of melting than previously thought by University of South Australia Credit: CC0 Public Domain But ice shelves, which are floating sheets of ice connected to a landmass's coasts, melted at an accelerated rate, the report said. When sea ice melts, sea level does not change. Res. These charts show just how high sea levels will rise if Antarctica's ice continues melting at an alarming rate. But both of these data points are misleading. Well, actually, sea ice and land ice are not the same. They have different effects, too. The Antarctic Peninsula experienced the most severe melting, said the report. But with only a few years of data, he couldn’t say whether the retreat was a temporary, natural anomaly or a longer-term trend from global warming. Beijing ICP prepared NO.16065310-3, 19% of Antarctic ice sheet surface melted in past 20 years: report. A major review published in 2009 found that Rignot’s Pine Island Glacier finding hadn’t been a fluke7: a large majority of the marine glaciers of the Antarctic Peninsula were retreating, and their retreat was speeding up. A new NASA study says that Antarctica is overall accumulating ice. Of all ice in a glass of water continent to lose mass anyway predicted this behavior is restricted to warming. 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