The Greenland Ice Sheet has lost mass at an accelerating rate over the last two decades, but limits of early remote sensing restricted examination of localized change at an ice‐sheet‐wide scale. Updated 3:15 PM ET, Wed September 30, 2020. Fresh snow in late May and early June had delayed the start of ice loss season, in contrast to last year’s very high melt rates around the same time. Greenland's ice sheet contains enough water to, Melting from Antarctica, on the other hand, is. “And what we see is that it was relatively steady until a big increase in ice discharging to the ocean during a short five- to six-year period.”. Right now, Briner says current melt rates track closely with this worst-case scenario. The current melting … About 20 years however, ice melt started increasing, while snowfall remained the same; a pattern that has persisted throughout the last 10 years. They then contrasted that with the amount of snowfall each year, which is the way these glaciers get replenished. July 10, 2019 — Ice on the Greenland Ice Sheet doesn't just melt. The Brooklyn-Battery tunnel in lower Manhattan after Hurricane Sandy and back to normal. “We’ve been looking at these remote sensing observations to study how ice discharge and accumulation have varied,” said Michalea King, a researcher at Ohio State University’s Byrd Polar and Climate Research Center and a lead author of the study. Then the last intact ice shelf in the Canadian Arctic, the Milne Ice Shelf, did collapse losing a chunk of ice bigger than Manhattan to the ocean. But new research shows the rate of ice loss is ramping up, and will be the fastest in 12,000 years by 2100. Scott has written about science and technology for 20 years for publications around the world. Now, according to a new paper published in the journal Nature Communications Earth and Environment, Greenland’s glaciers have shrunk so much that even if global warming were to stop right now, the ice sheet would continue shrinking. Updated 3:15 PM ET, Wed September 30, 2020 Meltwater carves into the ice sheet near the Sermeq Avangnardleq glacier in Greenland in August 2019. They discovered that during the 1980s and 90s, the size of the ice sheet was maintained by a combination of snowfall accumulation and ice melting or calving from glaciers, retaining an equilibrium of sorts. © 2020 Forbes Media LLC. A chart provided by the study authors shows how rapidly Greenland's melt has accelerated, and how unprecedented it is compared to rates that occurred over the last 12,000 years. (It takes approximately 360 billion tons of ice to produce one millimeter of global sea-level rise.). MARLOWE HOOD, AFP . Greenland's melting ice sheet – in pictures Visitors look out on to free-floating ice jammed into Ilulissat Icefjord in Greenland during unseasonably warm weather in July 2019. Glacier retreat has knocked the dynamics of the whole ice sheet into a constant state of loss. This is suggested by new results from a groundbreaking international research project headed by DTU Space. EY & Citi On The Importance Of Resilience And Innovation, Impact 50: Investors Seeking Profit — And Pushing For Change, Michigan Economic Development Corporation BrandVoice. On 20 August 2020, scientists reported that the Greenland ice sheet lost a record amount of 532 billion metric tons of ice during 2019, surpassing the old record of 464 billion metric tons in 2012 and returning to high melt rates, and provide explanations for the reduced ice loss in 2017 and 2018. ", Greenland lost more ice last year than in any year on record, Millions more US homes are at risk of flooding than previously known, new analysis shows, a new study published in the journal Nature provides some answers, currently responsible for 20-25% of global sea level rise, Antarctica holds enough water to raise sea levels by about 200 feet, discovered alarming vulnerabilities in some of its most important glaciers, Flooding from sea level rise could cost our planet $14.2 trillion, study says, A report last year from the UN's Intergovernmental Panel on Climate Change, already causing problems in many coastal areas. Greenland’s ice sheet shrank between 10,000 and 7,000 years ago, and has been slowly cumulating over the past 4,000 years. By University of Arkansas November 21, 2020 University of Arkansas geosciences associate professor Matt Covington flies a drone on the Greenland ice sheet. Melting of the Greenland Ice Sheet (GrIS) is the largest single contributor to eustatic sea level and is amplified by the growth of pigmented algae on the ice surface, which increases solar radiation absorption. Opinions expressed by Forbes Contributors are their own. The top left map of the Greenland Ice Sheet shows the total number of surface melt days from January 1 through August 6, 2020. In terms of its potential to raise sea levels, Greenland is the world's second most important ice sheet, behind only Antarctica. The Greenland ice sheet is about the same size as the state of Alaska and 10,000 feet thick in places. Melt brings about more melt, as water pooling across the ice sheet absorbs more sunlight and further heats everything around it. In the 1980s and 1990s, Greenland’s ice maintained a rough equilibrium. Ice loss would accelerate even more once the top of the ice sheet, which rises to 10,000 feet above sea level, melts down to a lower and warmer level of the atmosphere. "Humanity has the knobs, and we can turn those knobs to decide what the ice sheet is going to do," he said. Only a few minor late-season melt events occurred in September and October. We present a 1986 through March 2020 estimate of Greenland Ice Sheet ice discharge. Under a scenario where humans continue to raise concentrations of heat-trapping gases in the atmosphere, Greenland's ice loss could reach unprecedented levels, with more than 35,900 billion tons of ice potentially lost by the end of this century. Obviously this is catastrophic, not only for the wildlife in the region – which is already suffering – but also because of the resulting rise of sea level, gradual though it may be, the effects will be noticeable. It contains enough ice to raise sea levels by 23 feet (7 meters). "And when you do that, and think about the direction that Greenland is heading this century, it's pretty clear we're in quite anomalous times.". Melting Of Greenland’s Ice Sheets Has Passed The Point Of No Return, Scientists Say Scott Snowden Contributor Opinions expressed by Forbes Contributors are their own. However, if the world resolves to slash emissions enough so that global warming peaks around 2050, ice losses this century could be held to 8,800 billion tons -- still a massive amount, but only enough to raise sea levels by about an inch, compared to the roughly 4 additional inches we can expect under a high-emissions scenario. Greenland surface air temperature changes from 1981 to 2019 and implications for ice‐sheet melt and mass‐balance change. 1 SEPTEMBER 2020 . "These results say that human decisions about our energy systems are truly important in deciding how much sea level rise we face from melting of Greenland's ice. What happens to Greenland's ice sheet and others around the globe will determine what the future holds for the millions of people living along the world's coasts. Holes in Greenland Ice Sheet Are Larger Than Previously Thought, Study Finds Holes that carry surface meltwater to the base of the Greenland ice sheet, called moulins, are much larger than previously thought, according to a new study based on observation and first-hand exploration by a team including a geologist from the University of Arkansas . That's why tipping points like Greenland's accelerate ice … Ice Sheet Melting Is Perfectly in Line With Our Worst-Case Scenario, Scientists Warn . Greenland’s ice sheet (shown) has advanced and retreated many times over millennia. October 1, 2020 8:04PM (UTC) The ice sheet that covers most of Greenland, the world's largest island, is on pace to start melting faster than it has in the past 12,000 years. Greenland's ice sheet will melt at its fastest rate in 12,000 years this century, a new study projects. Greenland's massive ice sheet may have melted by a record amount this year, scientists have warned. The researchers analyzed satellite data from more than 200 large glaciers that are draining into the ocean around Greenland and measured how much ice breaks off or melts from the glaciers and flows into the ocean. Consequently, even if climate change to halted, suddenly, enough damage has been done that the glaciers would continue to disappear into the oceans and there would not be enough snowfall by far to rebuild them during the winter. “We are measuring the pulse of the ice sheet — how much ice glaciers drain at the edges of the ice sheet — which increases in the summer,” King said in the researchers’ statement. Satellite data from the last 40 years shows that Greenland’s glaciers have passed a tipping point of sorts, where the snowfall that replenishes the ice sheet each year cannot keep up with the ice that is flowing into the ocean from glaciers. More information: Michalea D. King et al. Melt of Greenland ice sheet (GrIS) plays important roles in sea level change, global climate, and other areas of global environmental issues. Dynamic ice loss from the Greenland Ice Sheet driven by sustained glacier retreat, Nature Communications Earth & Environment (2020). All Rights Reserved, This is a BETA experience. The Greenland and Antarctic ice sheets, which hold enough frozen water to lift oceans 65 metres, are tracking the UN's worst-case scenarios for sea level rise, researchers said Monday, highlighting flaws in current climate change models. Throughout this two decade period, the researchers found that the ice sheets lost on average about 450 billion tons of ice each year from flowing outlet glaciers, which was replaced with snowfall. Wednesday, November 18, 2020. The paper was coincidentally released on the same day that the US National Oceanic and Atmospheric Administration reported that July 2020 was the second-warmest July on record and that Arctic ice is currently at a record low for summer – the lowest in 42 years of record-keeping. Even if global warming were to stop today, the ice sheet would continue shrinking. But in the context of Earth's 4.5 billion-plus year history, melting in any one year or even a few decades amounts to the blink of an eye. Greenland's ice sheet experienced the largest outright drop in "surface mass" — or how much mass is lost due to melting compared to mass gained … But there may very well be mechanisms that are not picked up by the current models for how fast the ice is melting in Greenland. This biological albedo-reducing effect and its impact upon sea … Since 2000, the ice sheet has experienced a general increase in melting, with melt-day area for 2019 totaling 28.3 million square kilom… Last week, the world was given two more harsh reminders of what the future holds as residents of Italy’s Aosta valley were told to evacuate, fearing that a huge portion of the Mont Blanc glacier – the equivalent size of Milan cathedral – might collapse. Satellite microwave remote sensing has been increasingly used to produce maps of snow melt over Greenland during the past decades. Scientists estimate that if all of Greenland's ice melted, sea levels would rise by 23 feet. The big difference between now and then? Abstract. In 2012, category two Hurricane Sandy clipped New York City, causing $70 billion in damage, flooding subway tunnels and the Brooklyn-Battery tunnel – and that was a 14 foot storm surge. (CNN)We've known for some time now that Greenland's ice sheet is melting at an alarming rate. How much Greenland melts going forward is up to us. The ice sheet then started the melt season on 22 June – around 10 days later than average. Surface melting on the Greenland ice sheet ramped down at a near-normal pace in the weeks following the major melt event of early August (Figure 1). The ice sheet that covers most of Greenland, the world's largest island, is on pace to start melting faster than it has in the past 12,000 years. Overall, melting on the Greenland ice sheet for 2019 was the seventh-highest since 1978, behind 2012, 2010, 2016, 2002, 2007, and 2011 (Figure 2). Greenland's ice sheet dumps more than 280 billion metric tons of melting ice into the ocean each year. In 2019, Greenland's ice sheet lost 15% more ice than the previous record set in 2012, the study found. Each year the sheet lost some 400bn tonnes of ice in the summer—both by ice and snow melting … Over the last two decades, Greenland's ice sheet has melted at a rate of roughly 6,100 billion tons per century, a rate approached only during a warm period that occurred between 7,000 and 10,000 years ago. The top right map shows the difference between total 2020 melt days and the number of 1981 to 2010 average melt days from June 21 through August 1. It contains enough ice to raise sea levels by 23 feet (7 meters). The Greenland ice sheet is about the same size as the state of Alaska and 10,000 feet thick in places. Greenland's ice sheet -- which contains enough water to raise global sea levels by 24 feet -- is melting as fast as at any time in the last 12,000 years, a new study finds. Meltwater carves into the ice sheet near the Sermeq Avangnardleq glacier in Greenland in August 2019. Meltwater from the Greenland ice sheet represents the largest contribution to current global sea level rise. Whether the rapid disintegration we're seeing on Greenland today compares to anything that has happened in the past is a question on which the science is not completely clear. You may opt-out by. The ice actually slides rapidly across its bed toward the ice sheet's edges. During this year alone, it lost enough ice to … Back in April, a study published in The Cryosphere suggested that atmospheric circulation patterns contributed in a significant way to Greenland’s rapid loss of ice and as such, the future melt forecasts could’ve been underestimated by half. The influence of human activity. We position gates near the present-year termini and estimate problematic bed topography (ice thickness) values where necessary. Until 2000, the main driver of sea level rise was melting glaciers and the expansion of ocean water as it warms. In the 20th century, Greenland has lost around 9,000 billion tons of ice in total, accounting for 25 millimeters of sea-level rise. “What we’ve found is that the ice that’s discharging into the ocean is far surpassing the snow that’s accumulating on the surface of the ice sheet.”. "Clearly, the sea level rise from melting ice 12,000 years ago also affected people, but those people were much more widely spread out, and they didn't have parking garages and integrated modern water systems serving millions of people," said Richard Alley, a professor of geosciences at Penn State University who was not involved with the study published by Nature. "We know there's a lot of year-to-year variability, so what we were interested in doing is capturing the more meaningful trends over decades and maybe up to a century," said Jason Briner, a professor of geology at the University at Buffalo and the lead author of the study. The melting seen today is driven primarily by greenhouse gas emissions, whereas the warming that occurred thousands of years ago was a result of natural climate variability, Briner said. Study co-author Ian Howat, professor of earth sciences and distinguished university scholar at Ohio State said, “Even if the climate were to stay the same or even get a little colder, the ice sheet would still be losing mass.”. He covers environmental technology for Forbes. Our data include all discharging ice that flows faster than 100 m yr −1 and are generated through an automatic and adaptable method, as opposed to conventional handpicked gates.
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