What to Believe in Antarctica’s Great Ice Debate

Jul 6, 2017

By Shannon Hall

Our fate is tied to a frozen desert at the bottom of the world. Should Antarctica’s ice sheets dissolve, sea levels would rise dramatically—enough to flood the world’s great coastal megalopolises from New York to Shanghai and push millions of people inland. But determining just how the vast and frigid continent is currently responding to a warming world has been a challenge.

In West Antarctica the story is relatively clear. The floating platforms of ice that ring the coast are thinning, glaciers are surging toward the sea, meltwater is flowing across the surface, fast-growing moss is turning the once-shimmering landscape green and a massive crack threatens to cleave an iceberg the size of Delaware into the ocean. But in East Antarctica, where rising temperatures have caused increased humidity and thus more snowfall, the story takes an unexpected turn.

Most scientists agree that East Antarctica—unlike its western counterpart—is gaining mass in the form of snowfall, ice or both. But how much? And is it enough to counterbalance West Antarctica’s accelerating losses? A recent study published in Geophysical Research Letters by Alba Martin-Español from the University of Bristol and his colleagues suggests the gains in East Antarctica are so small that the continent is losing mass overall. This is just one in a long line of studies that disagree with rather controversial findings published in the Journal of Glaciology in 2015, which suggested that Antarctica is gaining mass. That study sparked a dizzying debate—but one that will ultimately help glaciologists grasp just what is happening in East Antarctica, and push scientists to consider how to handle contentious results in a warming world.

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12 comments on “What to Believe in Antarctica’s Great Ice Debate

  • I see the July 2017 edition of The National Geographic Magazine has articles on the latest from Al Gore:

    Why have such sharp political divi-sions emerged over climate change?
    There’s an old saying in Tennessee: If you see a turtle on the top of a fence post, you can be pretty sure it didn’t get there on its own. A determined minority— with active financial support from a
    few large carbon polluters—has held up progress for quite a while. They have used lobbying power and the threat of financing primary opponents, using the same techniques we saw in the past with Big Tobacco to falsely create doubt. All of us are vulnerable to what
    psychologists call denial: If something is uncomfortable, it’s easier to push it away, to not engage. But the solution is to listen and approach people on the basis of where they are.
    What gives you hope for the future?
    There are so many people working around the world on this that I am ex-tremely optimistic. It would certainly be helpful to have policies and laws that speed up our response. But market forces are working in our favor. Solar, wind, and other technologies are getting
    cheaper and better. More cities and com-panies are pledging to go 100 percent renewable. I believe the sustainability revolution is unstoppable.

    . . . and a special report on the ice of East Antarctica.

    In this two-part feature, see how scientists on Antarctica’s icy surface are tracking the continent’s meltdown, which could raise sea levels dramatically and cause a global crisis.
    In Part 2, visit the rarely seen and exotic marine world below.

    Seen from above, the Pine Island Ice Shelf is a slow-motion
    train wreck. Its buckled surface is scarred by thousands of large crevasses. Its edges are shredded by rifts a quarter mile across. In 2015 and 2016 a 225-square-mile chunk of it broke off the end and drifted away on the Amundsen Sea. The water there has warmed by more than a degree Fahrenheit over the past few decades, and the rate at which ice is melting and calving has quadrupled.

    The ice shelf is the floating terminus of the Pine Island
    Glacier, one of several large glaciers that empty into the
    Amundsen Sea. Together they drain a much larger dome of ice
    called the West Antarctic Ice Sheet, which is up to two and a
    half miles thick and covers an area twice the size of Texas. The
    ice sheet is draped over a series of islands, but most of it rests
    on the floor of a basin that dips more than 5,000 feet below
    sea level. That makes it especially vulnerable to the warming
    ocean. If all that vulnerable ice were to become unmoored,
    break into pieces, and float away, as researchers increasingly
    believe it might, it would raise sea level by roughly 10 feet,
    drowning coasts around the world.
    The ice sheet is held back only by its fringing ice shelves—
    and those floating dams, braced against isolated mountains
    and ridges of rock around the edges of the basin, are starting to fail. All around the Amundsen Sea, on the Pacific coast of West Antarctica, the ice shelves are weakening and the glaciers behind them are retreating as the ice flows faster into the sea. The Pine Island Ice Shelf, about 1,300 feet thick over most of its area, is a dramatic case: It thinned by an average of 150 feet from 1994 to 2012. But even more worrisome is the neighboring Thwaites Glacier, which could destabilize most of the West Antarctic Ice Sheet if it collapsed.
    “These are the fastest retreating glaciers on the face of the Earth,” says Eric Rignot, a glaciologist at the NASA Jet Propul-sion Laboratory in Pasadena, California. Rignot has studied the region for more than two decades, using radar from air-craft and satellites, and he believes the collapse of the West Antarctic Ice Sheet is only a matter of time. The question is whether it will take 500 years or fewer than a hundred—and
    whether humanity will have time to prepare.
    “We have to get these numbers right,” Rignot says. “But we have to be careful not to waste too much time doing that.”
    Getting the predictions right requires measurements that can be made only by going to the ice. In December 2012 a red-and-white Twin Otter plane skimmed low over the Pine Island Ice Shelf. The pilot dragged the plane’s skis through the snow, then lifted of and circled back to make sure he hadn’t uncov-ered any crevasses. After the plane landed, a single person disembarked. Tethered to the plane by a rope and harness, he probed the snow with an eight-foot rod.
    Finally the scout was satisfied: There were no buried cre-vasses that might swallow a landing party. More scientists got out of the plane. The team, led by glaciologist Martin Trufer of the University of Alaska, proceeded to set up camp. Their plan was to spend two months on the ice shelf; they would be the first humans to spend even a single night. The ice had long been considered too dangerous to visit. But
    Trufer’s team wanted to bore holes all the way through the ice shelf, so they could measure the heat eating at it from the seawater below.
    As the researchers lay in their tents at night, in the middle of a 4,000-mile arc of coastline that lacked a single permanent outpost, they heard loud pops and bangs coming from the ice. Each morning they saw new cracks, an inch wide and seemingly bottomless, cutting across its surface.
    During their five weeks of studying it, the ice un-der their boots thinned by another seven feet.
    IT TOOK SCIENTISTS A LONG TIME to real-ize just how quickly West Antarctica’s ice could melt. In part that’s because the most vulnerable glaciers are so well guarded. In front of the Pine Island Ice Shelf—the floating end of the glacier— the sea surface itself freezes each winter. In sum-mer this fractured sea ice joins icebergs calved from the ice shelves to form a shifting palisade that historically kept ships t least a hundred miles from the ice shelf.

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  • @OP- In West Antarctica the story is relatively clear. The floating platforms of ice that ring the coast are thinning, glaciers are surging toward the sea, meltwater is flowing across the surface, fast-growing moss is turning the once-shimmering landscape green and a massive crack threatens to cleave an iceberg the size of Delaware into the ocean. But in East Antarctica, where rising temperatures have caused increased humidity and thus more snowfall, the story takes an unexpected turn.

    In both the west and the east the story of melt from below the ice by warm ocean currents from the north, is increasingly being investigated!


    Shells record West Antarctic glacier retreat

    Scientists are getting a much clearer picture of the retreat of the West Antarctic Ice Sheet over thousands of years, and of the forces driving it.

    New research indicates that warm waters pulled up from the deep by strong winds sharply undercut glaciers from about 11,000 years ago to 7,500 years ago.

    This incursion then stopped until it got under way again in the 1940s.

    The findings are important because they inform our understanding about how the ice may respond in the future.

    Today, the big glaciers that enter the ocean in a key sector called the Amundsen Sea Embayment are in a rapid withdrawal.

    These ice streams, such as Pine Island and Thwaites glaciers, are colossal in scale – and their melting has become a significant contributor to global sea-level rise at around 1mm per decade.

    The glaciers’ grounding lines – the places where they enter the ocean and become buoyant – are heading inland; as are the floating segments, or shelves, they push out in front themselves.

    Dr Claus-Dieter Hillenbrand, a senior marine geologist at the British Antarctic Survey, explained: “We know today that the ice sheet in the Amundsen Sea is mainly influenced by this warm deep-water upwelling, which is very effectively melting the undersides of the ice shelves and weakening them, and because these shelves buttress the glaciers we therefore get the thinning of the glaciers, the acceleration in the flow speed of the glaciers and the retreat of their grounding lines.”

    Dr Hillenbrand and colleagues have been examining the shells of tiny marine organisms called foraminifera recovered from ocean-floor sediments in the Amundsen Sea Embayment.

    These shells have chemical “fingerprints” that record the nature of the water in which they were formed.

    For example, the ratio of different trace metals in the shells says something about how cold or warm the water was. And the different types of carbon incorporated into the shells reveal information about the age of the water.

    For example, scientists would like to get a detailed description of conditions during the last interglacial – the last major warm period on Earth – about 120,000 years ago.

    Researchers suspect the West Antarctic Ice Sheet at that time became extremely denuded.

    The big question is whether it could experience a similar withdrawal as the Earth warms as a consequence of rising levels of atmospheric carbon dioxide.

    “As you know there are some computer models which say a West Antarctic Ice Sheet collapse has potentially already begun,” Dr Hillenbrand told BBC News.

    His team’s study has been published in the journal Nature.

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  • A very nice documentary on the relocation of the British Antartic Survey Halley VI base, 23km inland because of ice breakup


    (The food looks awesome.) A chain of Pods on skis looking decidedly space agey are dragged one at a time inland and reassembled. Not to give the ending away but, they discover new cracks that make even the new location unsafe. As people cannot be rescued in winter Halley has been abandoned for the first time in many decades.

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  • Meanwhile – the latest development:


    One of the biggest icebergs ever recorded has just broken away from Antarctica.

    The giant block is estimated to cover an area of roughly 6,000 sq km; that’s about a quarter the size of Wales.

    An US satellite observed the berg on Wednesday while passing over a region known as the Larsen C Ice Shelf.

    Scientists were expecting it. They’d been following the development of a large crack in Larsen’s ice for more than a decade.

    The rift’s propagation had accelerated since 2014, making an imminent calving ever more likely.

    The more than 200m-thick tabular berg will not move very far, very fast in the short term. But it will need to be monitored. Currents and winds might eventually push it north of the Antarctic where it could become a hazard to shipping.

    An infrared sensor on the American space agency’s Aqua satellite spied clear water in the rift between the shelf and the berg on Wednesday. The water is warmer relative to the surrounding ice and air – both of which are sub-zero.

    “The rift was barely visible in these data in recent weeks, but the signature is so clear now that it must have opened considerably along its whole length,” explained Prof Adrian Luckman, whose Project Midas at Swansea University has followed the berg’s evolution most closely.

    The European Sentinel-1 satellite-radar system should also have acquired imagery in recent hours to confirm the break. Sentinel can sense any changes in the giant block’s motion relative to the shelf.

    @OP – What to Believe in Antarctica’s Great Ice Debate

    Maybe this is not happening!
    The deniers who don’t know how to measure or what to say so! 🙂 – so what do these space scientists and glaciologists know about collapsing ice sheets, ice shelfs, and warming ocean currents?

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  • phil rimmer #3
    Jul 11, 2017 at 8:48 am

    A very nice documentary on the relocation
    of the British Antartic Survey Halley VI base,
    23km inland because of ice breakup


    The advance party sent in to open up Britain’s mothballed Antarctic base have found no damage.

    Halley station was closed in March and staff withdrawn because of uncertainty over the behaviour of cracks in the Brunt Ice Shelf – the flowing, floating platform on which it sits.

    The base was secured and left to the elements, with temperatures dipping down to around -50C.

    But the first arrivals say Halley is none the worse for its shut-down.

    The British Antarctic Survey (BAS) flew a party of 12 into the base to start switching all the utilities back on – the power and heating.

    One fear was that windows might have broken in a storm and that this could have allowed snow to get inside. But that has not been the case.

    Halley operations manager John Eager said: “The team was very pleased to find the station in such good shape. It’s testament to how well last season’s team carried out the shut-down just after we successfully re-located the modules 23km inland.

    “Apart from a few carpet tiles lifting, and some crazing on inner glazing, everything is exactly as we left it. It is early days in the season, and many complex challenges remain, but it’s a great start by the team on the ice.”

    Some further technical investigations are being carried out to assess how well all the materials and equipment faired during winter.

    Halley is now being prepared for the annual southern summer influx of scientists in the coming weeks.

    The Royal Research Ship Ernest Shackleton is also expected soon with supplies.

    Together with the Rothera base on the Antarctic Peninsula, Halley spearheads British activity on the White Continent.

    The station gathers important weather and climate data, and it played a critical role in the research that identified the ozone “hole” in 1985.

    In recent years, Halley has also become a major centre for studying solar activity and the impacts this can have on Earth.

    So it looks like it will be operational again soon!

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  • Two thoughts come to mind.

    When does a president, in office, not in power and at the service of his nation, become criminally negligent in not availing himself of expertise and why not?

    Isn’t a parliamentary democracy and a decent sized politically buffered civil service just so much better, so much less purchased or manipulated?

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  • It’s become clear from this administration how vulnerable we are when such a large number of important government positions transition over to the entourage of the newly elected President and his political party. This time around, the situation has served us very badly. I hear nothing said about changes to this system but if we can’t have top notch experts in high positions that are hired based on superior qualifications, and perform their duties with accountability, then we will be doomed to descent into the idiocracy. I see no sign of changing this system since both political parties seem pleased with the zero sum game that we are playing here.

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