Supraglacialslipsialidosis

From the University of Colorado at Boulder, worry over something that is a natural process that has happened for thousands of years. You gotta love this one: ” Catastrophic lake drainages were 3.5 times more likely to occur during the warmest years than the coldest years.”. Gee, ya think? Or how about this one: “Once the water reaches the ice sheet’s belly that abuts underlying rock, it may turn the ice-bed surface into a Slip ‘N Slide, lubricating the ice sheet’s glide into the ocean.”. Hmm well, the “may” weasel word says that they really don’t know. The Greenland ice sheet is up to 1.8 miles (3 kilometers.) thick in the middle, and that huge weight depresses the underlying crust, which assumes the concave shape of a saucer. So I guess I’m not too worried about it slip-sliding away. And as WUWT has covered before, the warming in Greenland has some issues.

CU-Boulder study shows Greenland may be slip-sliding away due to surface lake melt

Like snow sliding off a roof on a sunny day, the Greenland Ice Sheet may be sliding faster into the ocean due to massive releases of meltwater from surface lakes, according to a new study by the University of Colorado Boulder-based Cooperative Institute for Research in Environmental Sciences.

Such lake drainages may affect sea-level rise, with implications for coastal communities, according to the researchers. “This is the first evidence that Greenland’s ‘supraglacial’ lakes have responded to recent increases in surface meltwater production by draining more frequently, as opposed to growing in size,” says CIRES research associate William Colgan, who co-led the new study with CU-Boulder computer science doctoral student Yu-Li Liang.

During summer, meltwater pools into lakes on the ice sheet’s surface. When the water pressure gets high enough, the ice fractures beneath the lake, forming a vertical drainpipe, and “a huge burst of water quickly pulses through to the bed of the ice sheet,” Colgan said.

Caption: This is a surface or "supraglacial" lake on the Greenland Ice Sheet. Credit: Konrad Steffen, University of Colorado

The study is being published online today by the journal Remote Sensing of the Environment. The study was funded by the Arctic Sciences Program of the National Science Foundation.

The researchers used satellite images along with innovative feature-recognition software to monitor nearly 1,000 lakes on a Connecticut-sized portion of the ice sheet over a 10-year period. They discovered that as the climate warms, such catastrophic lake drainages are increasing in frequency. Catastrophic lake drainages were 3.5 times more likely to occur during the warmest years than the coldest years.

During a typical catastrophic lake drainage, about 1 million cubic meters of meltwater — which is equivalent to the volume of about 4,000 Olympic swimming pools — funnels to the ice sheet’s underside within a day or two. Once the water reaches the ice sheet’s belly that abuts underlying rock, it may turn the ice-bed surface into a Slip ‘N Slide, lubricating the ice sheet’s glide into the ocean. This would accelerate the sea-level rise associated with climate change.

Alternatively, however, the lake drainages may carve out sub-glacial “sewers” to efficiently route water to the ocean. “This would drain the ice sheet’s water, making less water available for ice-sheet sliding,” Colgan said. That would slow the ice sheet’s migration into the ocean and decelerate sea-level rise.

“Lake drainages are a wild card in terms of whether they enhance or decrease the ice sheet’s slide,” Colgan said. Finding out which scenario is correct is a pressing question for climate models and for communities preparing for sea-level change, he said.

For the study, the researchers developed new feature-recognition software capable of identifying supraglacial lakes in satellite images and determining their size and when they appear and disappear. “Previously, much of this had to be double-checked manually,” Colgan said. “Now we feed the images into the code, and the program can recognize whether a feature is a lake or not, with high confidence and no manual intervention.”

Automating the process was vital since the study looked at more than 9,000 images. The researchers verified the program’s accuracy by manually looking at about 30 percent of the images over 30 percent of the study area. They found that the algorithm — a step-by-step procedure for calculations — correctly detected and tracked 99 percent of supraglacial lakes.

The program could be useful in future studies to determine how lake drainages affect sea-level rise, according to the researchers. CIRES co-authors on the team include Konrad Steffen, Waleed Abdalati, Julienne Stroeve and Nicolas Bayou.

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78 Responses to Supraglacialslipsialidosis

  1. 4 eyes says:

    Does anyone know the temperature at the interface of the rock and and the bottom of the ice sheet?

  2. DirkH says:

    “During a typical catastrophic lake drainage, about 1 million cubic meters of meltwater — which is equivalent to the volume of about 4,000 Olympic swimming pools”

    That would be 250 cubic meter of water per Olympic swimming pool.
    “Olympic size pools measure: 50 metres long, 25 metres wide, and a minimum of 2 metres deep.”
    http://wiki.answers.com/Q/How_much_water_does_an_Olympic_sized_swimming_pool_hold

    That’s a minimum of 2,500 cubic meters.

    What’s an order of magnitude amongst friends. Did they use a GCM to compute that?

  3. spangled drongo says:

    And that very cold meltwater could also fall 3klms into much colder regions to refreeze and grout things back together even tighter.

  4. Bill says:

    Is it possible that the water that is near its freezing point could re-freeze as it is cooled passing through a mile of ice and then act as a glue to cement the ice sheet to the rock? This seems like a 3rd possibility in addition to the slip-n-slide or the “sewer” idea.

  5. wayne Job says:

    Now I am terrified that umteen million cubic miles of ice is about to slide off into the ocean. I cannot sleep tonight as billions of souls will perish in with the rising of the seas. Then I keep reading and they say maybe the opposite is true, then I feel better.

    Perhaps nothing is happening that is not normal, maybe a good plumber needs to access the situation.

  6. ZootCadillac says:

    Interesting. Once the hand-wringing and doom starts from the usual suspects perhaps we could distract them for a moment with some news that ought to cheer them up. It’s not as bad as we thought.

    Himalayan glaciers actually GAINING ice, space scans show

  7. devijvers says:

    From the abstract:

    It is unclear whether this [increased surface meltwater production] will ultimately increase or decrease the basal sliding sensitivity of interior regions of the Greenland Ice Sheet.

  8. wilt says:

    Slightly off topic, a question about Arctic sea ice: am I the only one to notice that the Hansen data (Arctic Roos) have not been updated since April 5, twelve days ago ?! Satellite problems? Can anyone comment on this?

  9. David Middleton says:

    The Connecticut-sized area is near Jacobshaven, where the ice sheet is thin.

    The Greenland ice sheet covers an area of ~122 Connecticuts.

    The Greenland ice sheet has a volume of 10.4 trillion olympic-sized swimming pools.

    The “catastrophic lake drainages” may either destabilize or stabilize the Greenland ice sheet.

    Why did these grad students merit a Eureka Alert?

  10. CodeTech says:

    Um… the water can’t lubricate an ice sheet’s slide unless the water gets actually underneath the main bulk of the ice. Simply having some flowing water around the bottom is not the same as lubricating it for motion.

    Either someone doesn’t understand ice or they are counting on the reader not understanding ice, or “cold” in general… if the first, why are they pontificating about it, if the second, what’s their scam?

  11. Mike McMillan says:

    Much of the central axis of Greenland is 200 feet below sea level, with mountains around the periphery. With enough warming before the next ice age, we may get Lake Greenland, but she’s not gonna slide nowhere.
    map –
    http://i44.tinypic.com/r10nd0.jpg
    cross-section –
    http://i41.tinypic.com/r045n6.jpg

  12. Bob says:

    Lakes were monitored over a 10-year period and “as the climate warms.” Seems like an awfully short period of time to define a climatic warming trend. Also the lake drainage is described as catastrophic. I find it a stretch to define a natural event that apparently harms no one and happens rather frequently as “catastrophic.” When people are killed or massive property damage happens, then draining of one of these lakes might be catastrophic. Why lakes and not pools of melt water?

  13. Mike McMillan says:

    Actually, I meant central Greenland is 200 meters below sea level, not 200 feet.. I always have trouble converting feet to Olympic swimming pools.

  14. Tucker says:

    I’m betting the house on subterranean sewers. Since Greenland has undergone numerous periods in which it was warmer in the past than now (and didn’t slide slide away from inside it’s bowl), one should be able to safely say that the future holds similar results. What I find interesting is that I made this simple deduction at 7am while sipping coffee for a minute or two. Are we to conclude that these researchers over several years of study considered “slip and slide” and “sewers” under the context of our temperature past and concluded that the “slip and slide’ best represented the evidence?? What a sad scientific discipline climate science has become.

  15. beesaman says:

    I think we need to do some research into how many climate related papers start out with an alarmist argument, then conclude, after much modelling, that it is all a mystery but we need to do further research because we ‘know’ it is all bad just not how much.
    The sad thing is that this attitude is spreading out into other disciplines.

  16. Tucker says:

    ZootCadillac says:
    April 17, 2012 at 3:33 am

    How can that be? The Himalayas will have melted by 2035, or 2305, or 2350, 0r 2503, or 2530. Take your pick. Unless the Himalayas are hit with a massive drought the likes of which have not been seen in our historical record, I not going to lose any sleep over snow and ice melt at 20-30km up now or ever.

  17. R Barker says:

    What does all the melting and draining do to the ice core measurements?

  18. bernie1815 says:

    Is “catastrophic” the new “wicked”? Hyperbole drives me nuts unless it involves a joke.

  19. ZootCadillac says:

    Tucker says:
    How can that be? The Himalayas will have melted by 2035, or 2305, or 2350, 0r 2503, or 2530. Take your pick. Unless the Himalayas are hit with a massive drought the likes of which have not been seen in our historical record, I not going to lose any sleep over snow and ice melt at 20-30km up now or ever.

    Unfortunately the article and review are both behind a paywall at Nature Geosciences so I don’t know the details. However the article at El Reg states:

    The study was carried out by comparing two sets of space data, the first gathered by instruments aboard the space shuttle Endeavour in 2000 and the second by the French SPOT5 satellite in 2008. The results were unequivocal. Across the targeted 5,615km2 region of the Karakorum mountains lying on the Chinese border with India and Pakistan, the glaciers had gained substantial amounts of mass by the time the second survey was carried out. Satellite pictures had previously shown the glaciers there spreading to cover more area, but some climate scientists had argued that they might nonetheless be losing ice by becoming thinner: this has now been disproven.

    Something about not shooting messengers.

  20. Joe Ryan says:

    The funny this is that the song “Slip Sliding” is a rather appropriate theme song for CAGW and CAGW modeling: “You know the nearer your destination/ the more your slip sliding away”

  21. I like the way these events are described as ‘catastrophic’ lake drainages.
    Catastrophe
    An event causing great and often sudden damage or suffering.
    The denouement of a drama, esp. a classical tragedy.
    The only thing slippery about this study is the use of the English Language!

  22. Don J. Easterbrook says:

    I haven’t crawled around under the Greenland ice sheet but I have crawled around beneath the Iceland ice cap and large alpine glaciers in Alaska. What I saw was pretty amazing–lots of shearing within the base of the ice and many subglacial drainage tunnels. What I came away with was a fuller appreciation of what we already knew from borehole deformation–glaciers are not brittle masses of ice sliding along on their base like a brick; a good deal of the movement of ice is by basal shearing within the ice itself. The area under a glacier whose base is not frozen to the underlying rock is already wet, with abundant evidence of plenty of meltwater. But the meltwater isn’t distributed as a flowing film between the ice and rock–it is concentrated in numerous subglacial channels that don’t really affect basal sliding that much. So adding more water doesn’t really decrease the coefficient of friction between the ice and its base very much because it is already wet there. So how likely is it that drainage of supraglacial lakes is going to cause the Greenland ice sheet to ‘slide into the sea’? This is a geofantasy that could only be imagined by a computer model that has never seen a real glacier.

    Another aspect of this geofantasy is if melting of surface ice (which is a perfectly natural process that is not unique to the present), why hasn’t the ice sheet slid into the ocean before. We know from the Greenland ice cores that for all but the last few thousand years,, the climate for the past 10,000 years has been warmer than present. So during all of that time, why don’t we see any evidence at all of the phenomena these authors are postulating? Most likely because it hasn’t happened before. If there is no evidence that this has never happened in the past, why should we worry about it happening now in a climate that isn’t even as warm as most of the past ten millenia?

  23. Shevva says:

    There really is a lot of chaff in the scientific world these days, lucky they don’t influence Goverment policy in anyway.

    I assume the scientist are vrying for Disney Land Ice World a heater and you got a water park.

  24. Andrew says:

    A floating ice scultpure of Mike Mann’s pointy head? Could tow it slowly down to Iceland and hold the next winter olympics on it… the IPCC could maybe sponsor the ice hockey comp??

  25. Jack says:

    Does no one in the press understand about friction and mass?

  26. Steve from Rockwood says:

    Don J. Easterbrook says:
    April 17, 2012 at 5:13 am
    ————————————–
    Thanks for that common sense Don.

  27. Andrew says:

    …and the opening gala night could feature famous warmists being thrown to the polar bears whilst 10,000 choreographed Emperor penguins do a crazy kindof 70’s smooch to AbbA’s ‘Dancing Queen’ as the marvellous northern lights weave their magic across the polar sky…lovely.

  28. Dan Lee says:

    When the ice sheet goes, I want to be on top of it. That’s going to be one heck of a ride on the biggest surfboard ever! Maybe we could direct it over toward the Sahara or something, do some good.

    — Sorry, just trying to see the world through Alarmist eyes. It seems to look like it did when I was a teenager.

  29. Colin Richardson says:

    An earlier study ( http://www.guardian.co.uk/environment/2011/jan/26/greenland-ice-sheet-climate-change ) appears to have ruled out “catastrophic” slippage.

  30. Brian H says:

    “We have a model of a catastrophic fantasy! More funding, please?
    →$$$
    Thankyew, thankyew!!!”

  31. Bloke down the pub says:

    Has anyone tried to find out where the water that dissappears down the sink holes re-emerges? Perhaps if they tipped a load of yellow plastic ducks down one there could be a competition to see who’s duck got home first.

  32. Bill Tuttle says:

    CIRES co-authors on the team include Konrad Steffen, Waleed Abdalati, Julienne Stroeve and Nicolas Bayou.

    *The* Waleed Abdalati? The Big Kahuna of NASA playing a bit part in a scenario written by a research assistant and a grad student? WUWT?

  33. JL says:

    Further to Don Easterbrook’s comment, the mechanism proposed in this paper is not particularly new in terms of understanding the interactions between sudden inputs of water to the glacier bed(‘catastrophic’ i.e. rapid in this context – for those balking at the termminology) and glacier movement. As Don rightly mentions, there is a complex network of drainage pathways beneath the ice. What matters, during supraglacial lake drainage is the volume of water that reaches the bed vs. the ability of the subglacial drainageways to evacuate this water. In a situation where the volume of water and the rate at which the water reaches the bed (more importantly) are so large that they exceed the capacity of the drainage networks to evacuate the water, subglacial water pressure can increase to the point of localy lifting the ice of its bed and allowing water to effectively spead laterally beyond the margins of the subglacial channel. This happens whether the subglacial channels are in bedrock or sediment (thought the mechanics are slightly different). There is an added complexity in the fact that as the water drains, it also melts the ice and enlarges existing tunnels by ‘eroding’ and melting the ice. At the same time, the ice deforms to fill this gap (but usually at a much slower rate than the water flow). Again, this reinforces the idea that these are short-lived events. When water spreads laterally, the ice is effectively sliding on a layer of water. There have been a number of cases in alpine glaciers, Antarctica, and Greenland that show a localized acceleration of the glacier after lake drainage.

    Sea-level would increase (by a minuscule amount for one of these drainage events) if the meltwater reaches the ocean and IF formerly grounded ice moves into the ocean to form a shelf or icebergs. The important things here is that these events are localized and short-lived (transient). The idea that the whole ice sheet is slip-sliding away is beyond fantasy. It is a real travesty that scientific results are written in such a way!

  34. JL says:

    Re: Bill and R Barker

    It is a very valid question to ask how much of the lake water actually makes it out of the glacier. Depending on the geometry of the ice and the glacier bed, the meltwater flowing at the base can refreeze to the base of the ice (this is seen in Iceland and recently in Antarctica). Therefore, not all of the lake water necessarily goes to sliding, and not all the water actually reaches the ocean. How much is a big unknown and determined by the local conditions (lake volume, bed topography, etc.)

    – R barker

    This freezing ice would potentially have an effect on ice core measurements, especially since the isotopic composition of the refrozen water at the base would originate from the surface or from melting of glacier ice. Most ice cores are taken near the summit of the ice sheets where there little to no surface melting and hence little chance of contamination. However, a recent study in Antarctica (profiled on WUWT)

    http://wattsupwiththat.com/2011/03/08/east-antarctic-ice-sheet-getting-thicker-from-underneath/

    showed that a lot of water (generated by melting at the base of the ice) could flow and refreeze to the base of the ice far into the centre of the ice sheet. Again, the local conditions are critical so it is definitely buyer beware when extrapolating and drawing broad conclusions.

  35. Bloke down the pub says:
    April 17, 2012 at 5:47 am
    …Perhaps if they tipped a load of yellow plastic ducks down one there could be a competition to see who’s duck got home first.

    ROFLMAO. Oh, the visuals!

  36. johnmcguire says:

    Brian H got it right. They want more money to keep their gravy train running. Say something scarey and get more money to study the non-issue to death. Those people ,like so many sucking on the agw teat, are pathetic. By the way Anthony, I like your title to this rediculousness.

  37. Alberta Slim says:

    Don J. Easterbrook says:
    April 17, 2012 at 5:13 am

    Thanks for some REAL info, Don.
    Those “researchers” should be attending ‘Bolder’ U as their computer generated musings
    are just a waste of time and money.
    Has Boulder U any credibility?

  38. tty says:

    I hope nobody thinks that there is anything new about all this. Here is how A. E. Nordenskiöld describes the Greenland icecap from a visit in july 1870 in approximately the sama area as the current study:

    “After the melting of the snow there appears besides a number of inequalities, and the clefts previously covered with a fragile snow-bridge now gape before the wanderer where he goes forward, with their bluish-black abysses, bottomless as far as we can depend on ocular evidence. At some places there are also to be found in the ice extensive shallow depressions, down whose sides innumerable rapid streams flow in beds of azure-blue ice, often of such a volume of water as to form actual rivers. They generally debouch in a lake situated in the middle of the depression. The lake has generally an underground outlet through a grotto-vault of ice several thousands of feet high. At other places a river is to be seen, which has bored itself a hole through the ice-sheet, down which it suddenly disappears with a roar and din which are heard far and wide, and at a little distance from it there is projected from the ice a column of water, which, like a geyser with a large intermittent jet in which the water is mixed with air, rises to a great height.”

    Note that this was the first time ever that a scientist penetrated the Greenland Icecap, and that it happened right at the end of the Little Ice Age. Plus ça change, plus c’est la même chose.

  39. TomL says:

    One comment on the bowl-shape of the land surface: The land surface of Greenland is depressed below sea level *because* of the weight of the ice sheet. If or when the ice sheet melts, the land surface will rise over a period of several thousand years. The phenomenon of “glacial isostatic rebound” has been very well documented in areas formerly covered by ice. Northern Scandinavia and FInland are probably the best example.

  40. gregole says:

    Mike McMillan says:
    April 17, 2012 at 3:56 am
    “Much of the central axis of Greenland is 200 meters below sea level, with mountains around the periphery…”

    Mike – thanks for the comment and the cross sections. Where did you get those, they are great. I’ve added them to my Greenland files. Here’s a map further illustrating your point:

    http://commons.wikimedia.org/wiki/File:F1_large2.JPG
    * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
    Don J. Easterbrook says:
    April 17, 2012 at 5:13 am

    “I haven’t crawled around under the Greenland ice sheet but I have crawled around beneath the Iceland ice cap and large alpine glaciers in Alaska…”

    Don, thanks for taking time to make an informed, expert comment to lend some reality to the discussion.

    One time some years ago, when I was in the military, young adventurous and foolish, I was on duty in Alaska and rode a bike up to a glacier – alone. I ventured out some ways on the glacier having no idea what kind of danger I was exposing myself to. I wandered in far enough that I couldn’t clearly see features from where I came – probably a half mile to a mile. I can still see that place in my minds eye: cold, dry, brilliantly white, quiet but for the wind.

  41. Ian E says:

    ‘Supraglacialslipsialidosis’ – isn’t that when you get a smelly infection above your tonsils and they have to feed you ice cream as it’s the only thing that will slip down?

  42. Tucker says:

    Zoot Cadillac,

    I was being facetious. All is well.

  43. P van der Meer says:

    R Barker says:
    “What does all the melting and draining do to the ice core measurements?”

    It is my guess that all these lakes only form near the coast and than only in summer where the altitude is low enough for the temperature to get just above freezing. But in the centre of the Greenland plateau the altitude is high enough so that the temperature never gets above freezing. It is for that reason that the GISP2 ice core station is situated in the centre of Greenland, because any surface melting would otherwise destroy the information contained in the ice cores.

  44. tty says:

    By the way those subglacial drainage channels aren’t just theory. On Svalbard where glaciers are thinner and the ice is quite cold (and stiff) they sometimes remain open in winter and it is actually possible to penetrate up to several kilometers beneath the glaciers:

    Humlum, O et al. 2005: Late-Holocene glacier growth in Svalbard, documented by subglacial relict vegetation and living soil microbes. The Holocene 15(3):396-407

    available here: http://epic.awi.de/11679/1/Hum2005a.pdf

  45. They use the c word many times. I used a different c word when I read this nonsense.

  46. Wellington says:

    Study: The draining of meltwater pools may have a lubricating effect. “Alternatively, however”, it may not.

    These budding scientists seem to also have studied their tautological tables and learned how to make unfalsifiable statements—the bedrock of climate science.

    The influence of the study co-author and NASA Chief Scientist Waleed Abdalati is undeniable.

  47. Peter Miller says:

    I read this post twice to make sure my BSometer was correct – so water drains down a freezing column over 2kms thick. By the time it hits bedrock – if it ever does – it will be a crystal mush which will rapidly freeze. Remember, the temperature of this water will only be just above freezing as it starts its journey. As the water refreezes, it will expand and act as a very effective cement.

    OK, there are going to be shear zones within the ice, which will be open, but if water does enter them it will rapidly refreeze. If the supposed problem suggested here was real, it would be in the record of recent (last 8,000 years) changes in ocean levels. Is it there? Answer: No. So like most things to do with ‘climate science’, it is a non-problem, but a scary non-problem.

    But this comment says it all: ““Lake drainages are a wild card in terms of whether they enhance or decrease the ice sheet’s slide,” Colgan said. Finding out which scenario is correct is a
    pressing question for climate models and for communities preparing for sea-level change.”

    The translation is: “Gimme more grant money, and gimme it now!”

  48. higley7 says:

    As water is more dense than ice under some conditions, there is good likelihood that water is present at the bottom of the glacier anyhow as heat migrates up from the interior of the crust.

    Meltwater is an annual reality and to think that it suddenly becomes a lubricant better than normal is fear mongering, Boogeyman in the closet propaganda.

    What we should really be worrying about is the obvious number of really stupid and/or dishonest scientists out there and how dangerous they are and can be. I get the feeling that stupid level has been rising as government funds melt in their pockets. Soon we will be over our heads with stupid!

  49. Bill Illis says:

    Borehole temperature measurements from NGRIP which reached bedrock show that the glacier is -30C on top, -32C as you get down to 1500 metres and then is actually melting at the bottom of the glacier at 3000 metres down due to the geothermal heat propagating up. The temperature at the bottom is -2.4C but due to the pressure, it is enough for liquid water.

    So there is already some liquid water at the bottom of the glacier although the conditions might be slightly different in different locations than NGRIP.

    http://www.iceandclimate.nbi.ku.dk/research/flowofice/borehole_logging/

    Just noting that models of how temperatures migrate through the glacier is how they have calibrated the isotope measurements in Greenland and what provides the estimate of a decline in temperatures of -20C at the last glacial maximum in Greenland. I think there are significant errors in these borehole thermometry models.

  50. Jim B in Canada says:

    OFF TOPIC

    There is yet another biased poll being used for political purposes here http://www.inews880.com/index.aspx

    I was wondering if the WUWT crowd would come on and vote for sanity.

  51. geologyjim says:

    Yes, it’s the perfect climate-science paper. Based on automated-scanning data and feature-recognition software (BUT, honest, we manually checked 30% of 30% of the observations!! soooooo boring), you conclude that “catastrophic” lake-drainage could:

    1) Rapidly accelerate glacier flow to the ocean (slip-slidin’, ticklin’ the belly hypothesis), or

    2) Seize-up glacial flow toward the ocean (sub-glacial sewer hypothesis).

    Whatever happens, you’ve got it covered. And there’s no way to test either hypothesis

    Is this great science, or what?!??

    Next paper will use a model with “algorithms” to calculate the size of the tsunami when the ice cap catastrophically slides into the Atlantic. Bye, bye Florida!

  52. Don J. Easterbrook says:

    As JL points out, the only way that sudden discharges of meltwater can spread laterally between the base of a glacier and its bed is if the water pressure becomes high enough to lift the glacier off its bed to allow the water to spread. That can happen locally in alpine glaciers where the ice is thin relative to water pressure and may speed up glacial motion. But the Greenland ice sheet is more than 10,000 feet thick. Think how much water pressure would be needed to lift that thickness of ice.

  53. David Jones says:

    “During summer, meltwater pools into lakes on the ice sheet’s surface. When the water pressure gets high enough, the ice fractures beneath the lake, forming a vertical drainpipe, and “a huge burst of water quickly pulses through to the bed of the ice sheet,” Colgan said.”

    Thery have, of course, calculated the pressure (i.e. weight) of the water on the ice surface and what weight is necessary to make a crack in the ice 1.8km deep………….No? I thought not!!

    Good heavens, a kid at elementary school would get detention for writing rubbish like this!

  54. David Jones says:

    Jim B in Canada says:
    April 17, 2012 at 7:50 am

    OFF TOPIC
    There is yet another biased poll being used for political purposes here http://www.inews880.com/index.aspx
    I was wondering if the WUWT crowd would come on and vote for sanity.”

    I voted: Score at that time: Yes 23.4% No 76.6% I’ll come back in 2 hours and vote again!

  55. Here’s something else to think about. The water/ice phase relationship is pressure dependent–you can melt ice which is below the freezing point by applying enough pressure. When Ice freezes, it increases in volume. If you apply enough pressure, the ice/water equilibrium relationship tends to revert to the phase with smaller volume (water). Ice in temperate glaciers is usually close to the pressure-melting point. Where basal meltwater exists under substantial ice thickness, it is generally below the atmospheric freezing point of water (0 degrees C; 32 degrees F). Research in Iceland and Alaska glaciers has shown that when such water is forced to rise upward to the surface under hydrostatic pressure, the water will refreeze onto the base of the glacier. I’ve seen this happening at the termini of Alaskan glaciers. If subglacial water at the base of the Greenland ice sheet were to rise up several hundred meters out of its basin, it would surely be supercooled and would freeze onto the base of the glacier.

  56. John from CA says:

    4 eyes says:
    April 17, 2012 at 3:10 am

    Does anyone know the temperature at the interface of the rock and and the bottom of the ice sheet?
    ======
    There are a couple of Greenland hot springs in the area of the Southern tip and mid Western coastal areas but there is also this about other hotspots.

    Byrd Polar Research Center
    at Ohio State University

    2007
    OSU Research News, December 7. Earth’s Heat Adds to Climate Change to Melt Greenland Ice. Article discusses Ralph von Frese‘s research into “hotspots” under Greendland which may be melting the ice above or enabling ice to slide more rapidly out to sea.

    “COLUMBUS , Ohio — Scientists have discovered what they think may be another reason why Greenland ‘s ice is melting: a thin spot in Earth’s crust is enabling underground magma to heat the ice.”

    “They have found at least one hotspot in the northeast corner of Greenland –just below a site where an ice stream was recently discovered.”

    source: http://researchnews.osu.edu/archive/hotgreen.htm

  57. John from CA says:

    John from CA says:
    April 17, 2012 at 8:33 am

    There are a couple of Greenland hot springs in the area of the Southern tip and mid Western coastal areas but there is also this about other hotspots.
    s/b
    There are a couple of Greenland hot springs in the area of the Southern tip and Eastern coastal area but there is also this about other hotspots.

  58. Hal says:

    I live in Iowa.
    Somebody please alert me when Greenland has crossed the Canadian border.
    I don’t want to be caught unprepared.

  59. kbray in california says:

    I can simplify this physical event for evaluation.
    I suggest the following experiment:

    Freeze 1 square foot of ice, 2 inches thick.
    Drill 1/4 inch holes in the ice every 2 inches.
    Also chill 2 quarts of water to 32 degrees F,
    so that it starts to freeze.
    Put 1/2 inch of sand on a card table.
    Place the ice in the middle of the card table.
    Pour 1 quart of water over the ice to fill all the holes with “high pressure water”.
    Drink the other quart to stay properly hydrated during observation.
    Watch it just sit there.
    Keep watching until the ice melts.

    I see no reasonable force presenting itself causing the ice to move.

    The only way to get that ice to move would be to position a dike around the ice to capture enough melt water to “float” the ice off of the sand. Getting the ice close to floating would reduce the coefficient of friction enough so that the wind could move the ice, but the dike would keep it from falling off the table.

    Suggesting the ice sheet will slip off Greenland is not logical.

    Tilting Greenland to the same angle of a roof, could help the ice sheet “slip off” however one must consider imbalance and the “tipping over” of the whole Island as presented by Hank Johnson and the Island of Guam:

    Maybe the above “Hank’s Phenomenon” is what they are referring to.

  60. MAC says:

    Massive flooding was a common occurrence 15,000 years ago from Lake Missoula when glacial ice would float when enough water dammed behind it releasing a torrent of water that flooded across Idaho and Eastern Washington. As climate warmed from 15,000 to 13,000 years the number of flooding from this glacial ice dam increased.

    “Thousands of varves were deposited in Lake Missoula. At the best-known Ninemile locality near Missoula, about 40 rhythmites consist of varves overlain by a sand/silt layer [Figs. 61, 62]. The varves were deposited on the floor of Lake Missoula, and the sand/silt layers represent subaerial
    exposure and deposition in a stream. The number of varves in each rhythmite varies from 9 to 40, decreasing regularly upward, and the total number of varves is just less than one thousand.
    An interpretation of these data would suggest: [1] Lake Missoula filled and emptied [in a catastrophic flood] about 40 times, [2] it took 9 to 40 years to fill the lake, each successive lake requiring less time, and [3] the process was repeated over a period of about one thousand
    years. Because Ninemile is about in the middle of the very long lake, the record here would not provide a complete history of the lake. Correlating Ninemile with the downstream record would suggest these events were in the latter half of the entire flood history.
    http://geology.mines.edu/faculty/Klee/Missoula.pdf

    Nothing new….

  61. Funny how these authors basically sensationalize basic glacier physics…their olympic-sized swimming pools will have long frozen once they get below the ice.

  62. highflight56433 says:

    Such bunk writing. Just another indication of the poor quality of professors allowing junk newspaper style research. A total waste of funding going into what we already know is that Greenland during warm periods is GREEN. Scary stuff.

  63. SteveSadlov says:

    If you look at the Google satellite view of Greenland, it appears that glaciers there in starting to surge. Seems like things are in or soon will be in a growth mode. The real worry is not reduction in the overall glacial mass there. The real worry would be, glaciers forming shelves into the Davis Strait. If a glacier jumps the Davis Strait, we are in a whole new (scary) mode.

  64. Paul Marko says:

    Mike McMillan says:
    April 17, 2012 at 3:56 am

    “Much of the central axis of Greenland is 200 feet below sea level, with mountains around the periphery. With enou
    gh warming before the next ice age, we may get Lake Greenland, but she’s not gonna slide nowhere.”
    map –
    http://i44.tinypic.com/r10nd0.jpg

    The map shows topographic drainage toward central Greenland from both east and west coastlines. Any lake drainage would flow towards Greenland’s interior not the ocean.

  65. Robert Clemenzi says:

    What about Lake Vostok?

    If “1 million cubic meters of meltwater” are something to worry about, then wouldn’t something the size of Lake Ontario (though much deeper) be a bigger issue?

    1e6 m3 vs 5,400 km3 = 5.4e12 m3

    And that is only one of about 140 lakes nuder the ice.

  66. rogerkni says:

    Bloke down the pub says:
    April 17, 2012 at 5:47 am
    Has anyone tried to find out where the water that dissappears down the sink holes re-emerges? Perhaps if they tipped a load of yellow plastic ducks down one there could be a competition to see who’s duck got home first.

    They did this about five years ago, with thousands of ducks. I think I saw an article in color on it in a science magazine. (I no longer subscribe to such.) Dunno if they came out.

  67. kbray in california says:

    Speaking of the North Arctic…

    Looks like the Blue line is likely to “slip and slide” into the Gray line…

    http://nsidc.org/data/seaice_index/images/daily_images/N_timeseries.png

    I hope it makes a loud noisy crunching colliding sound when it happens…
    Charts could be more exciting with audio enhancements.

  68. Bob Diaz says:

    I’m surprised no one has posted this video yet:

  69. JohnBUK says:

    HAL said:
    “I live in Iowa.
    Somebody please alert me when Greenland has crossed the Canadian border.
    I don’t want to be caught unprepared.”
    Brilliant!
    Just to be on the safe side – pick up the phone to me in the UK and leave it connected. When it disconnects you’ll know it’s passed the UK.
    Good luck everyone its worse than we thought.

  70. Miss Grundy says:

    “Here’s something else to think about. The water/ice phase relationship is pressure dependent–you can melt ice which is below the freezing point by applying enough pressure. When Ice freezes, it increases in volume. If you apply enough pressure, the ice/water equilibrium relationship tends to revert to the phase with smaller volume (water). ”

    *****************
    I believe that’s the principle behind ice skating. The weight of the skater on thin blades exerts a momentary strong pressure on the ice, which melts and allows the skater to glide forward. The momentarily-melted water re-freezes once the skater has moved on.

  71. Ally E. says:

    Catawicked, in my opinion.

  72. Resourceguy says:

    If the study area is on the flank of the ice sheet where the ice is thin, I suppose you could get water flow out from the sheet but in itself is a false reference to the main ice sheet where the basal rock is depressed into a bathtub shape. So why is this not not discussed more even if it is not adequately explained by the researchers or the press? We would not want to give up too much info now would we. More facts only confuses the masses anyway.

  73. kbray in california says:

    “THEY” KEEP MOVING THE GOAL POSTS !!

    Just above I posted this:

    kbray in california says: April 17, 2012 at 10:56 am
    Speaking of the North Arctic…
    Looks like the Blue line is likely to “slip and slide” into the Gray line…

    I noticed today that someone has adjusted the lines further apart….

    Steve Goddard at Real Science shows what “they” did here:

    http://www.Real-Science.com/breaking-news-nsidc-gets-in-the-data-tampering-act#comments

    This is anthropogenic manipulation by a##holes.

  74. kbray in california says:

    Here is a better link to Steve’s post:

    http://www.Real-Science.com/breaking-news-nsidc-gets-in-the-data-tampering-act

    REPLY:
    Yeah its a processing glitch. I’ve been in touch with NSIDC and they are working to fix it…no nefarious motives there – Anthony

  75. kbray in california says:

    REPLY: Yeah its a processing glitch. I’ve been in touch with NSIDC and they are working to fix it…no nefarious motives there – Anthony
    ——————————————————————————–
    Giving the benefit of the doubt….ok…

    …but it does give one pause to wonder…
    I have noticed “adjustments” more than once.

    If I knew more about their process, it’s easier to be more forgiving.
    I imagined that they were only processing a number, but it must be more involved than that.

    Seeing “manipulation” over and over makes for a short fuse and a quickness to pounce.
    Apologies are hereby presented.

  76. Brian H says:

    kbray;
    since all such “errors” are in the direction of hyping and exaggerating AGW “trends”, no apologies are warranted. There is prima facie evidence of manipulation and fudging from stem to stern in climastrology.

  77. Richard S Courtney says:

    Miss Grundy:

    At April 17, 2012 at 4:57 pm you present a common misunderstanding when you say;

    “I believe that’s the principle behind ice skating. The weight of the skater on thin blades exerts a momentary strong pressure on the ice, which melts and allows the skater to glide forward. The momentarily-melted water re-freezes once the skater has moved on.”

    Sorry, but No!

    All solid ice is coated with a liquid phase at all temperatures down to less than -40 deg.C.

    This surprising fact was first discovered by Michael Faraday (of electricity fame) and has been subject to much study since. It is important for several reasons which include the fallacious arguments of the study reported in the above article. (And an amusing ‘home experiment’ demonstrates this strange property of ice surface; see below).

    Firstly, the effect occurs because the bonds which link ice molecules exist in the ice but not outside the ice’s surface. Hence, normal vibration of the ice molecules induces a transition between solid and liquid properties in a surface layer.

    Hence, ice is slippery because its surface is wet, and skaters slide on the liquid phase which coats the surface of the ice.

    Similarly, if introduction of liquid water beneath a glacier is to reduce friction between the glacier and the underlying ground then the introduced water must lift the glacier above the surface roughness of the ground. Introduction of a thin layer of water makes no difference because the bottom of the glacier (i.e. ice) is always coated with a very thin layer of water.

    Also, the liquid phase occurs between molecules of liquid ice. This must affect compositions of gas samples ‘trapped’ in ice. Gases dissolve in water and different gases have different solubilities. Ionic diffusion of gases through the liquid phase between molecules can be expected to alter relative concentrations of gases in parts of the ice over time.

    The ‘home experiment’ is as follows.

    1.
    Place an ice cube on top an empty wine bottle.
    2.
    Attach a heavy weight to each end of a length of thread.
    3.
    Place the thread across the ice cube such that the weights hang down the sides of the bottle.
    4.
    Wait (and occasionally watch) for some hours.
    5.
    The thread travels down through the ice cube until the thread rests on top the bottle. The ice cube then shows no visible indication that the thread has passed through it.

    This happens because the weights pull the thread through the liquid phase on the ice surface. This creates new ice surface below the thread, but this new surface also has a coating of liquid so the thread is pulled through that. The solid reforms above the ice (with no distortion) because the liquid phase is only a surface effect. If the thread were to ‘cut’ the ice by a pressure effect (as you suggest) then the ice cube would exhibit visible evidence that the thread had ‘cut’ it.

    Richard

  78. Richard S Courtney says:

    Aaargh!

    In my above post I wrote;
    “Also, the liquid phase occurs between molecules of liquid ice. This must affect compositions of gas samples ‘trapped’ in ice. Gases dissolve in water and different gases have different solubilities. Ionic diffusion of gases through the liquid phase between molecules can be expected to alter relative concentrations of gases in parts of the ice over time.”

    That is nonsense. I intended to write.
    “Also, the liquid phase occurs between crystals of ice. This must affect compositions of gas samples ‘trapped’ in ice. Gases dissolve in water and different gases have different solubilities. Ionic diffusion of gases through the liquid phase between crystals can be expected to alter relative concentrations of gases in parts of the ice over time.”

    Sorry.

    Richard

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