In this 2011 photo provided by researcher Hamish Pritchard, summer clouds swirl around the Staccato Peaks of Alexander Island off the Antarctic Peninsula. In a study released Wednesday, June 13, 2018,... (Associated Press) 
 
 In this 2011 photo provided by researcher Hamish Pritchard, summer clouds swirl around the Staccato Peaks of Alexander Island off the Antarctic Peninsula. In a study released Wednesday, June 13, 2018, an international team of ice experts said the melting of Antarctica is accelerating at an alarming... (Associated Press) 
 
 WASHINGTON (AP) — The melting of Antarctica is accelerating at an alarming rate, with about 3 trillion tons of ice disappearing since 1992, an international team of ice experts said in a new study. 
 
 In the last quarter century, the southern-most continent's ice sheet — a key indicator of climate change — melted into enough water to cover Texas to a depth of nearly 13 feet (4 meters), scientists calculated. All that water made global oceans rise about three-tenths of an inch (7.6 millimeters). 
 
 From 1992 to 2011, Antarctica lost nearly 84 billion tons of ice a year (76 billion metric tons). From 2012 to 2017, the melt rate increased to more than 241 billion tons a year (219 billion metric tons), according to the study Wednesday in the journal Nature . 
 
 "I think we should be worried. That doesn't mean we should be desperate," said University of California Irvine's Isabella Velicogna, one of 88 co-authors. "Things are happening. They are happening faster than we expected." 
 
 Part of West Antarctica, where most of the melting occurred, "is in a state of collapse," said co-author Ian Joughin of the University of Washington. 
 
 The study is the second of assessments planned every several years by a team of scientists working with NASA and the European Space Agency. Their mission is to produce the most comprehensive look at what's happening to the world's vulnerable ice sheets in Antarctica and Greenland. 
 
 Outside experts praised the work as authoritative. 
 
 Unlike single-measurement studies, this team looks at ice loss in 24 different ways using 10 to 15 satellites, as well as ground and air measurements and computer simulations, said lead author Andrew Shepherd of the University of Leeds in England. 
 
 It's possible that Antarctica alone can add about half a foot (16 centimeters) to sea level rise by the end of the century, Shepherd said. Seas also rise from melting land glaciers elsewhere, Greenland's dwindling ice sheet and the fact that warmer water expands. 
 
 "Under natural conditions we don't expect the ice sheet to lose ice at all," Shepherd said. "There are no other plausible signals to be driving this other than climate change." 
 
 Shepherd cautioned that this is not a formal study that determines human fingerprints on climate events. 
 
 Forces "that are driving these changes are not going to get any better in a warming climate," said University of Colorado ice scientist Waleed Abdalati, a former NASA chief scientist who wasn't part of the study team. 
 
 In Antarctica, it's mostly warmer water causing the melt. The water nibbles at the floating edges of ice sheets from below. Warming of the southern ocean is connected to shifting winds, which are connected to global warming from the burning of coal, oil and natural gas, Shepherd said. 
 
 More than 70 percent of the recent melt is in West Antarctica. 
 
 The latest figures show East Antarctica is losing relatively little ice a year — about 31 tons (28 metric tons) — since 2012. It was gaining ice before 2012. 
 
 So far scientists are not comfortable saying the trend in East Antarctica will continue. It is likely natural variability, not climate change, and East Antarctica is probably going to be stable for a couple decades, said study co-author Joughin. 
 
 Another study in Nature on Wednesday found that East Antarctic ice sheet didn't retreat significantly 2 million to 5 million years ago when heat-trapping carbon dioxide levels were similar to what they are now. 
 
 Twila Moon, a research scientist at the National Snow and Ice Data Center who wasn't part of the studies, said "ice-speaking, the situation is dire." 
 
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 Follow Seth Borenstein on Twitter: @borenbears . His work can be found here . 
 
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 The Associated Press Health & Science Department receives support from the Howard Hughes Medical Institute's Department of Science Education. The AP is solely responsible for all content. ||||| The ice front of Venable Ice Shelf, West Antarctica. (AFP photo/NASA/JPL-Caltech/UC Irvine) 
 
 Late last week, a study published by NASA scientists in the Journal of Glaciology made the surprising claim that the gigantic continent of Antarctica is actually gaining ice, rather than losing it, to the tune of 82 gigatons (or billion metric tons) per year from 2003 to 2008. 
 
 The study has drawn massive amounts of media attention — and no wonder. It contradicts numerous prior scientific claims, including a 2012 study in Science by a small army of polar scientists, a study from earlier this year in Earth and Planetary Science Letters (which found 92 gigatons of net losses per year) and this 2014 study in Geophysical Research Letters (160 gigatons of net losses per year). It also contradicts assertions by the leading consensus body of climate science, the U.N.’s Intergovernmental Panel on Climate Change, which stated in 2013 that Antarctica is “losing mass” and that this process is accelerating. That statement was itself based on multiple studies showing Antarctic ice loss. 
 
 Not only does the new research fly in the face of all of this — if true, it also raises serious questions about our current understanding of sea level rise. If Antarctica is actually gaining ice, that means that a significant percentage of the current rise of the seas, estimated at roughly 3.22 millimeters per year by NASA itself, must be coming from elsewhere. (It takes 360 gigatons of ice to raise seas by 1 millimeter). 
 
 No wonder, then, that a number of researchers have been quoted expressing skepticism about the new research, even as climate change doubters have had a field day — adding the study to an argumentative arsenal that previously included misleading claims about growing Antarctic sea ice. 
 
 So what’s going on here — and what should you make of the new claim that Antarctica isn’t losing ice or raising our seas? 
 
 Measurement disputes and burdens of proof. The new NASA study uses satellite data from NASA’s ICEsat (Ice, Cloud and land Elevation Satellite) and the European Remote-sensing Satellite to derive its results, which are based on precision measurements of the elevation of the ice sheet and how that is changing over time. The key finding is that snow-related mass gain atop the ice sheet is more than compensating for the flow of ice outward in glaciers that reach the sea. 
 
 “Our interpretation is that this has been going on since the beginning of the last ice age when the snowfall over the continent doubled, the accumulation over the continent doubled, as shown in ice cores,” says H. Jay Zwally, the lead author and a longtime NASA expert on the planet’s ice sheets and methods for studying them with satellites. 
 
 More specifically, the research asserts that a “dynamic thickening” of ice over time has occurred as a result of this snowfall. Or as a NASA explanation puts it, “This small thickening, sustained over thousands of years and spread over the vast expanse of these sectors of Antarctica, corresponds to a very large gain of ice – enough to outweigh the losses from fast-flowing glaciers in other parts of the continent and reduce global sea level rise.” 
 
 However, this contradicts many other results, including those derived using a different NASA tool — the GRACE satellites, twin measurement devices that orbit the Earth and measure the changing mass of ice based on differential tugs of gravity on the spacecraft as they pass over it. Accordingly, numerous scientists have expressed skepticism, to varying degrees, about the new research. 
 
 Andrew Shepherd, a glaciologist at the University of Leeds in the UK who was an author of one of the recent studies cited above finding net Antarctic mass loss, puts it this way in an e-mail to the Post: 
 
 Zwally and his team have tried to account for snowfall, which masks changes in the thickness of the polar ice sheets. It’s right to attempt this, but in places where nothing much happens – like the interior of Antarctica, which is a vast desert – it’s really quite difficult to be sure that snowfall can be simulated with enough precision to detect ice imbalance. Fortunately we now have many different ways to examine Earth’s ice sheets – from space and on foot – and I’m confident that we can get to the bottom of this contradiction by taking everything into account. 
 
 I also reached an author of the other study cited above finding a net mass loss using GRACE — geoscientist Christopher Harig of Princeton University. Harig defended the GRACE measurements and the finding that Antarctica is losing mass, and said that a key part of the difference between his research and the new study involves how researchers handle something called “glacial isostatic adjustment” or GIA, which refers to the rising of land as the weight of ice has been removed from it since the last ice age. 
 
 As Harig put it by e-mail: 
 
 GRACE gives us the most direct measurement of mass changes that we have currently. This paper, which uses laser altimetry, claims the discrepancy between our results is due to recent GIA model corrections being incorrect, and that GRACE is more sensitive to the error. If we add back the GIA corrections, and compare our results then, their estimates should agree with ours because we measure mass directly. Instead they are still very far away. Arguing that because their results are different, they must be better, is unsustainable. 
 
 Other scientists have also defended the GRACE approach, and criticized the new research. Al Jazeera, for instance, quoted two other top Antarctic researchers — NASA’s Eric Rignot and the National Snow and Ice Data Center’s Ted Scambos — expressing arguably stronger criticisms of the new work than those cited above. Rignot has published some of the most cited work on the rapid retreat and unsettling vulnerability of West Antarctica, and Scambos is an author of a recent study finding that strong winds are wearing down East Antarctica and likely adding 80 gigatons per year to sea level rise — results that pretty clearly trend in a very different direction from the new NASA study. 
 
 So there is plenty of skepticism out there — but at the same time, Zwally fully stands by the new research. “We have a very high confidence in our results,” he says. “We have examined the accuracy of our results quite carefully, we believe they’re accurate, and in the paper we report why they differ from other methods, and provide constructive critiques of why they differ.” 
 
 In an interview, Zwally also reiterated the notion that GRACE is more sensitive to how one treats glacial isostatic adjustment — clearly, a key point of dispute here. 
 
 What’s clear, then, is that we are looking at a significant scientific disagreement — one that turns on different technologies, methodologies, and adjustments. In such a situation, scientists will now need to hash this out and reconcile their understanding of what is happening to the gigantic snowy mass of East Antarctica in particular. 
 
 In the meantime, nonspecialists may understandably feel baffled by the technical details at play here. But here’s where they can be more confident: Since the new results contradict a lot of other findings, they will likely face a major challenge when it comes to convincing the Antarctic research community as a whole. 
 
 That’s no criticism of the scientists behind the new study — it’s simply how science works. And as the process plays out, it’s fair for scientists and outside observers alike to regard the new research as having to overcome a relatively high burden of proof, and to stay skeptical. 
 
 None of which means you should worry any less about Antarctica and sea level rise. In the meantime, the reasons for worry about Antarctica aren’t any less — and particularly when it comes to West Antarctica, a marine based ice sheet that some scientists fear has already begun a process of irreversible collapse. Indeed, a new study released Monday finds that accelerating mass loss in the glaciers of West Antarctica’s Amundsen sea region could undermine the entire ice sheet and set in motion an inevitable, if slow moving, 3.3 meter (or over 10 foot) rise in global sea levels. 
 
 All of the research groups involved here agree that a key part of West Antarctica is losing mass and that, if treated on its own rather than as part of the larger continent, is making a net positive contribution to sea level rise. The new NASA study only covers a period from 1992 to 2008, so it excludes more recent observations that other researchers have made in this area. Nonetheless, it too finds accelerating mass loss in one key part of West Antarctica that includes the closely watched Pine Island and Thwaites glaciers, growing from 60 gigatons per year between 1992 to 2001 to 97 gigatons per year between 2003 and 2008. 
 
 
 
 Undated photo of Thwaites glacier in West Antarctica. (AFP Photo/NASA/handout) 
 
 Zwally is skeptical about some of the more worrying takes on West Antarctic loss, but he certainly doesn’t deny that it’s happening. “There’s no reason to believe that the loss that we see now will not continue for a long time,” he says. “But there’s a serious question about whether it is still accelerating.” 
 
 Research drawing on more recent data, however, does suggest the loss rate continues to increase. Another NASA supported study of the Amundsen Sea region alone, published in late 2014, ran from 1992 all the way to 2013, and found that the melt rate had “tripled during the last decade.” 
 
 As for what’s actually happening to sea levels if Antarctica is a net gainer rather than loser of ice, Zwally says he thinks the ice is indeed coming from elsewhere — the possibilities include Greenland, the melting of smaller glaciers around the world, and more ocean heat leading to greater thermal expansion of seawater. 
 
 Any way you look at it, though, the bottom line is that we’re facing ongoing sea level rise — and an increasing mass loss from Antarctica or a decreasing mass gain (as the new study finds) would both make that problem worse. As Jamin Greenbaum, a researcher at the University of Texas at Austin who studies East Antarctica, put it by e-mail: 
 
 Unfortunately, this study doesn’t change the fact that sea level rise has been accelerating since around 1870. Actually, it suggests that Antarctica’s ability to slow that rise is decreasing due to alarming trends in coastal mass loss. For instance, in East Antarctica, Totten Glacier is losing enough mass on its own to balance mass gains in an area larger than Texas. 
 
 All in all, then, the current disagreement helps to underscore that even as humans begin to modify the biggest systems and features of the planet, scientists are still struggling to fully measure and comprehend those changes. 
 
 Until the current debate gets ironed out, then, there are several possible stances you can take, ranging from fully accepting the new study over the prior ones — as many climate change doubters seem to be doing — to dismissing it out of hand. But the most reasonable one is probably to regard these surprising new findings with a fair dose of skepticism — and to continue worrying about ice losses along the Antarctic coasts. 
 
 Read more in Energy & Environment: 
 
 Scientists confirm their fears about West Antarctica — that it’s inherently unstable 
 
 Scientists say illegal pot farming operations are poisoning threatened weasels 
 
 The huge paradox at the heart of how people think about environmental risks 
 
 For more, you can sign up for our weekly newsletter here, and follow us on Twitter here. ||||| This story was updated at 8:26 p.m. ET. 
 
 NASA recently released a study suggesting that the Antarctic Ice Sheet is gaining more ice than it is losing — a finding that, at first blush, seems to contradict the idea of global warming. So, how can Antarctica be gaining ice mass in a warming world where ice sheets are collapsing and the melting is predicted to increase sea levels across the globe? 
 
 It turns out that the two phenomena — a growing ice sheet and warming-related melting — are not mutually exclusive. Moreover, the NASA study, which was published Oct. 30 in the Journal of Glaciology, does not disprove global warming. 
 
 Rather, the researchers found that snow accumulation is adding more ice to East Antarctica (the huge chunk of the continent to the east of the Transantarctic Mountains) and the interior region of West Antarctica than is being lost as glaciers across Antarctica thin out. More snow accumulation is, counterintuitively, a sign of global warming; more precipitation happens when there is more moisture in the air, and more moisture in the air is a product of higher temperatures, said Elizabeth Thomas, a glaciologist with the British Antarctic Survey. [Infographic: Your Guide to Antarctica] 
 
 Ice elevation 
 
 Map shows notable features and facts about Antarctica. Credit: by Karl Tate, Infographics Artist 
 
 The NASA researchers made their observation on the current state of the Antarctic Ice Sheet — which covers an area roughly the size of the United States and Mexico combined — by taking altitude measurements using data collected by the European Remote Sensing (ERS) satellites between 1992 and 2001 and using the Ice, Cloud and land Elevation Satellite (ICESat) between 2003 and 2008. 
 
 The ERS satellites were equipped with radar altimeters, whereas the ICESat had a laser altimeter. An altimeter measures elevation by shooting a beam of radio waves (radar) or a beam of light (laser) to the ice surface. The altimeter records the time it takes the waves to bounce off the surface and back to the satellite. The higher the elevation, the quicker the return time, and vice versa. [See Stunning Photos of Antarctic Ice] 
 
 Then, the researchers mapped out how ice elevation had changed over time. They found that, although certain areas of Antarctica, such as the Antarctic Peninsula and the coastal parts of western Antarctica, are losing more ice than they are gaining, overall, the continent's ice is growing. 
 
 Specifically, between 1992 and 2001, snow accumulation added about 121 gigatons of ice per year, on average, where 1 gigaton equals about 1 billion U.S. tons. That number dropped to 82 gigatons per year between 2003 and 2008. 
 
 Controversy over the study 
 
 However, although the findings don't negate climate change or suggest warming is slowing down, they have been met with some pushback from the scientific community. 
 
 For example, the study doesn't include current data, leading some scientists to question whether the results are meaningful. 
 
 The most recent data in the study was from 2008, noted Michael Mann, a climate scientist at Pennsylvania State University. Many of the recent studies that demonstrate the range of ice loss take more recent data into account, Mann told Live Science. The study "is making a statement about the way things are today [using] a data set that is seven years out of date," he said. "If they used data that was up-to-date, they would find a higher rate of loss," Mann noted. 
 
 Using a RADARSAT dataset of Antarctica, an abandoned Russian station on top of frozen Lake Vostok is visible. It is in the left section of the lake in this image. Credit: NASA 
 
 Mann also mentioned that he knows of several ice experts who are a little skeptical of the elevation measurements in certain regions, such as the region surrounding Lake Vostok. Regions near large bodies of water have highly variable elevations because of the presence of liquid water, and it's not clear whether the NASA study accounted for this. [See Photos of a Subglacial Lake in Antarctica] 
 
 The results also contradict a finding detailed last year in the journal Earth and Planetary Science Letters, in which Christoper Harig, a geoscientist at Princeton University, and his colleagues found a net loss of ice covering Antarctica. They relied on GRACE measurements for their study. 
 
 Jay Zwally, a glaciologist with NASA Goddard Space Flight Center in Greenbelt, Maryland, and colleagues said in their Journal of Glaciology paper that the new results are more accurate than those in Harig's Gravity Recovery and Climate Experiment (GRACE) satellite study because they are based more on ICESat measurements, which according to Zwally, are better at adjusting for the rise and fall of land that happens when ice has been removed or added to it, respectively — a phenomenon called glacial isostatic adjustment (GIA). When ice melts, the land beneath it rebounds slightly as the weight is removed. It's critical to account for that rebound when measuring elevation, scientists say. 
 
 "This paper, which uses laser altimetry, claims the discrepancy between our results is due to recent GIA model corrections being incorrect, and that GRACE is more sensitive to error," Harig wrote in an email to the Washington Post, according to this WaPo report. "If we added back the GIA corrections, and compare our results, then their estimates should agree with ours because we measure mass directly. Instead, they are still very far away." 
 
 However, Mann said that, although the consensus among climate scientists is that Antarctica is, indeed, losing more ice than it is gaining, the new NASA study still demonstrates good science. 
 
 "This is the way science works; the scientific community is doing its best to understand and reconcile [the NASA study data]," he said. Even if the results can't be verified, Mann said, the research was conducted in good faith and shouldn't be dismissed as unimportant to the greater body of work. 
 
 Is Antarctica warming? 
 
 A portion of the East Antarctic Ice Sheet, called Wilkes Land, flowing into the ocean. Credit: Michael Hambrey (glaciers-online.net) 
 
 So, what is actually happening in Antarctica? The Antarctic is not warming as fast as the Arctic is, said Zwally, who led the NASA study. "It's more like the global change [rates]," Zwally said. In other words, the Antarctic region is seeing a regional temperature rise that matches the temperature rise seen on average around the world, instead of the much higher temperature rise in the Arctic regions noted by NOAA. Scientists think the Antarctic region is experiencing a slower temperature rise than the Arctic, because the ozone hole over Antarctic has created weather trends, specifically in East Antarctica, that has slowed it down. 
 
 "East Antarctica is not warming as fast as West Antarctica — that's the part of Antarctica that is the most susceptible to ice loss," Mann said. In 2007, researchers reported in the journal Geophysical Research Letters that they had found a link between this phenomenon and the ozone hole over Antarctica. Depleting ozone in the upper atmosphere changes wind dynamics there, Mann said. That change causes a strengthening of the jet stream and the polar winds, but it also traps the cold air in the regions around East Antarctica, creating a cooling effect. 
 
 An image of the ozone hole over Antarctica in early October 2015. Credit: DLR (German Aerospace Center) 
 
 As the ozone hole has gotten smaller, this cooling effect has mostly disappeared, Mann said, meaning that even East Antarctica will have warming rates comparable to global warming rates soon. 
 
 Zwally also noted that if the warming were to continue at current rates, the ice gains that the NASA study found would not continue. In other words, the melting would increase enough to offset the large amounts of snow building on the surface. 
 
 Trends over time 
 
 Other research has started to look at older records of Antarctica's climate, in order to place current data into historical context. Doing so can help scientists better understand how current observations fit into the larger story of Antarctica's climate. In a separate study, published Nov. 4 in the journal Geophysical Research Letters, researchers studied the climate of West Antarctica over the past three centuries by looking at ice core records. The researchers found that snow accumulation in the 20th century had been significantly higher than in the previous two centuries looked at in the study. 
 
 "It looks as though [this trend] is related to there being more storms [in West Antarctica]," said Thomas, of the British Antarctic Survey. "Just because [West Antarctica] is getting more snow doesn't mean that [the ice sheet is] getting thicker." 
 
 She explained that both higher snow accumulation and thinning ice sheets are results of the same regional warming phenomenon. The amount of precipitation is tied to the amount of sea ice in the region. "When we had a lot of sea ice, we don't have so much moisture," she said. 
 
 Going forward 
 
 It's clear that studying climate change is a complicated endeavor, but any climate scientist will stress the importance of understanding what's happening to Antarctica. "In terms of climate, [the process] is hugely complex, and [there is] a lot going on," Thomas said. It will take a lot of research to get a better understanding of what's happening there because records of the region date back only decades. 
 
 Moreover, further research should investigate the smaller changes happening in Antarctica that contribute to regional climate change, scientists say. 
 
 Editor's Note: This story was updated to show that the NASA study used ERS satellite data, not GRACE satellite data, between 1992 - 2001. GRACE was not launched until 2002. 
 
 Follow Elizabeth Newbern @liznewbern. Follow Live Science @livescience, Facebook & Google+. Original article on Live Science.
– Scientists monitoring ice loss in Antarctica have chilling news: The melting rate has accelerated alarmingly and the ice sheet is now shedding more than 200 billion tons a year, according to a study involving 88 scientists published in the journal Nature. The researchers say the rate of ice loss has tripled over the last decade and the melting ice sheets are now pushing up sea levels around the world by around a half-millimeter every year, reports the BBC. Antarctica was losing around 49 billion tons of ice a year in the mid-1990s, which went up to an average 219 billion tons a year between 2012 and 2017, the study found. The researchers, who used satellite data going back more than 25 years, say most of the melting ice comes from the West Antarctic sheet, parts of which are in a "state of collapse"—and modest ice growth in the East Antarctic is nowhere near enough to offset it. "The increasing mass loss that they’re finding is really worrying, particularly looking at the West Antarctic, the area that’s changing most rapidly," University of Waterloo glaciologist Christine Dow tells the Washington Post. "And it’s the area that we’re most worried about, because it’s below sea level." Antarctica has lost a total of around 3 trillion tons of ice since 1992 and will be contributing more and more to sea level rise if the current trend continues, warn researchers, who say climate change is the only plausible explanation for the ice loss. "I think we should be worried. That doesn't mean we should be desperate," says study co-author Isabella Velicogna of the University of California Irvine, per the AP. "Things are happening. They are happening faster than we expected."