Galloping Glacier Might be a Warning

October 2, 2018

Popular Science:

A researcher watching Russia’s largest High Arctic glacier was surprised when his gaze shifted to its nearby neighbor. What he saw there raised questions about how glaciers work—and what we may be facing as the world warms.

“I kept on seeing this other ice cap in the southern part of the scenes I was looking at via satellite,” says University of Colorado geologist Michael Willis. He was studying the Academy of Sciences Glacier, Russia’s largest, but what really caught his eye was the nearby Vavilov Ice Cap. It was doing something totally unexpected, he says: moving, and quickly. The ice cap—the term refers to a type of glacier, of which “polar ice cap” is a subset—is of a kind that’s supposed to be very stable. “This kind of ice cap shouldn’t be displaying this kind of behavior,” Willis says.

In this instance, though, the ice cap was practically galloping along: “surging” at a pace of 82 feet per day in 2015, as Willis and his colleagues found. Previously, its average speed was just about two inches per day. Using a combination of historic data from an earlier study, and data from two current satellite information systems, they traced the glacier’s movement and its degree of ice loss.

All glaciers “move” as ice freezes or melts on their edges, shifting their location. But it’s not just the ice visible from the air that’s important to this process—things happening deep under the surface have influence as well. One of these unseen processes might be behind the dramatic movement, says Willis. Over the period of study, he says, the bottom of the ice changed from “rough and sticky,” meaning stable, to “slick,” meaning there’s water down there lubricating the ice cap’s movement. The presence of water under the ice suggests the existence of a slightly warmer layer—or water somehow getting in from the surface.

This surprise matters—especially if it’s going to happen again elsewhere. Current climate models don’t take this kind of surge into account. But high-altitude glaciers of the same type of the Vavilov Ice Cap hold the potential to contribute about a foot to sea level rise. That means that all of the water currently held in these glaciers as ice, if it was melted back into the ocean, could potentially cause sea levels to rise by a foot.

“What we don’t have is a good enough satellite image catalog to know if these are kind of one-offs or this is something cyclical,” says University of British Columbia glaciologist Christian Schoof. Schoof points to another study of a glacier in Svalbard that shows a similar process. That study is in pre-print and unlikely to be published, but the data appears to be solid, he says.

Unlike other climate sciences—oceanography, for instance—there’s not a lot of great historical data on what glaciers in the world’s remote parts have been doing over the course of the last few hundred years. But Willis’s new paper might point to something historically notable. In general, glaciers like the Vavilov Ice Cap are predictable They’re machines trying to balance the input of snow and the output of climate influences on the ice, and generally, in the absence of forces changing the climate, quite stable, he says. “These surges are interesting because they don’t do that,” he says, which raises some questions about how we currently model this kind of glacier. Current predictions about melting may not be taking these kinds of movements from the glacier into account—or, if they’re cyclical, Schoof says, can’t say what will happen to the cycle in the presence of climate change.

In the case of the Vavilov Ice Cap, Willis says he’d be “hesitant” to link what happened directly to climate change. But “the sheer fact that it can do this is eye-opening,” he says. “We can call it an anomaly, but if it’s happened in one place it can happen elsewhere too.”

“This is a great example of something that can happen to ice sheets and to glaciers that we don’t understand particularly well,” Schoof says. That understanding may prove crucial to predicting things like sea level rise and glacier melt.

Willis and his colleagues started thinking about how to model the behavior of the Vavilov Ice Cap during their work on this paper, though that is not yet published. They hope to continue working on modeling for this kind of dramatic event. Schoof says that’s good, but also calls for more observation of the world’s High Arctic glaciers to help us better understand—and predict—their behaviors.

John Abraham in The Guardian:

What caused the rapid motion? This is an important question because if the motion is caused by human warming, we can expect the behavior to be repeated elsewhere as temperatures rise.  Importantly both air and ocean-water temperatures could be a factor.  One potential cause is surface meltwater.  The top of the ice can melt, and liquid water then can flow downwards, into the ice through cracks and holes.  This flowing water can precondition the ice for rapid motion.

This fact may be a contributing cause to the motion.  Basically, the melted water lubricated the ice/ground interface causing more sliding and more friction.  The friction caused some of the bottom ice to melt and released more liquid water, and a cycle had begun.

The researchers also took measurements of elevation to better understand areas where ice was becoming thicker or thinner.  In addition, they studied the forces that exist within the ice itself to help elucidate the cause of the increased speed. Obviously, this is an evolving area of study and all of the questions have not yet been answered.  However, I was impressed when I read that even though these types of surges are becoming more common, what the researchers observed in Russia was still unique.  They describe the rate of ice loss at Vavilov as “extreme.” The authors also point out,

So, to answer the question, how fast is it moving?  In 2015, it reached speeds of up to 82 feet in a single day. It currently is sliding 15–35 feet a day. For comparison, that is much faster than the average 2 inches per day we would see with no surge events.

The takeaway message is that once we thought these large bodies of ice responded slowly to changing conditions.  But this research shows us differently.  It shows that ice sheet can move quickly and once we pass a threshold, they may be hard to stop.  This finding makes it more crucial for us to slow down global warming before it’s too late.

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5 Responses to “Galloping Glacier Might be a Warning”

  1. Sir Charles Says:

    Rapid Collapse of the Vavilov Ice Cap, Russian High Arctic.

    Abstract

    Cold based ice caps and glaciers are thought to respond slowly to environmental changes. As sea ice cover evolves in the Arctic, a feedback process alters air-temperatures and precipitation patterns across the region. During the last decades of the 20th century the land-terminating western margin of the Vavilov Ice Cap, on October Revolution Island of the Severnaya Zemlya Archipelago, advanced slowly westwards. The advance was driven by precipitation changes that occurred about half a millennia ago. InSAR shows that in 1996 the margin sustained ice speeds of around 20 m/yr. By 2000 the ice front had moved a short distance into the Kara Sea and had transitioned to a marine-terminating front, although an ice apron around the ice margin indicates the ice there was still frozen to the bed and there is no evidence of calving in satellite imagery. In 2013 ice motions near the terminus had accelerated to around 1 m/day. By late 2015 the main trunk of the newly activated outlet glacier attained speeds of 25 m/day and the inland portion of the ice cap thinned at rates of more than 0.3 m/day. The acceleration of the outlet glacier occurred due to its advance over weak, water-saturated marine sediments that provide little resistance to ice flow, and to the removal of lateral resistive stresses as the glacier advanced out into an open embayment. Longitudinal stretching at the front forces an increase in the surface slope upstream. Rapid rates of motion inland generate frictional melt at the bed, possibly aided by cryohydrological warming. Large areas of the interior of the Vavilov ice cap are now below the equilibrium line and the grounded portion of the ice cap is losing mass at a rate of 4.5 km3 w.e./year. The changes at the Vavilov are likely irrecoverable in a warming climate due to a reduction in the accumulation area of the ice cap. Increased precipitation drove the advance, which accelerated due to the presence of soft sediments. The acceleration lowered the elevation of the interior portion of the ice cap to a point from which it cannot recover. A second, similar collapse seems to be underway at basin-2 on the southern margin of the Austfonna Ice cap in Svalbard.

  2. rhymeswithgoalie Says:

    I presume they’ve checked that there’s no local anomaly, like a geologic hot spot. (I was chary of James Balog’s ice project putting cameras on Iceland glaciers, which often have significant geologic heat component to their behavior.)

  3. redskylite Says:

    It is so sad to see the great glaciers of the world changing and diminishing so amazingly fast. Best to visit now before they’re completely gone. This report from China

    “If every country sticks to the emissions reductions in the Paris Agreement, these two glaciers will be around for another hundred years,” says Li. “If not, then temperatures will continue to rise, and the glacier we’re walking on? It’ll be gone in 50 years.”

    And that, says Li, is a problem for this entire region.

    These glaciers are the source of the Urumqi River, which provides water for half the city of Urumqi, the largest in the region and home to nearly 4 million people.

    But that is not all that is at risk.

    . . . . . . . .

    http://english.cas.cn/newsroom/news/201809/t20180929_197926.shtml

  4. redskylite Says:

    And this report from Sweden – so much for hoaxes

    Northern Swedish cities see the effects of climate change more than anywhere else in Europe

    One example is the melting of glaciers; earlier this year, a glacier on Sweden’s Kebnekaise mountain melted away so much that it lost its status as the country’s highest point. During July 2018, researchers found that the glacier had lost four metres of snow, meaning that an average of 14 centimentres melted each day of July.

    https://www.thelocal.se/20180926/swedens-northernmost-cities-are-getting-warmer-at-a-faster-rate-than-the-rest-of-europe

  5. redskylite Says:

    “A researcher watching Russia’s largest High Arctic glacier was surprised when his gaze shifted to its nearby neighbor. ”

    Quite frankly, having followed “Crocks” for quite a few years now (from when the Antarctic was thought of as mainly stable and pristine) I’m surprised that scientists still are surprised at what climate change is throwing at us now.

    It isn’t turning out to be a manageable comfortable linear controlled experiment that some had hoped for. Nature is way way mightier than that.


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