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Earth Space Science

ICE Satellite Maps Profound Polar Thinning 245

Posted by kdawson
from the skating-on-thin-ice dept.
xp65 writes "Researchers have used NASA's Ice, Cloud and Land Elevation Satellite to compose the most comprehensive picture of changing glaciers along the coast of the Greenland and Antarctic ice sheets. The new elevation maps show that all latitudes of the Greenland ice sheet are affected by dynamic thinning — the loss of ice due to accelerated ice flow to the ocean. The maps also show surprising, extensive thinning in Antarctica, affecting the ice sheet far inland. The study, led by Hamish Pritchard of the British Antarctic Survey in Cambridge, England, was published September 24 in Nature."
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ICE Satellite Maps Profound Polar Thinning

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  • by msevior (145103) on Sunday September 27, 2009 @02:13AM (#29554119)

    I'm no climate change skeptic, but from just looking at the images it's not clear that the reduction in some places is not balanced by the increase in others. What is the net effect? Can these data be compared to model predictions?

    • Re: (Score:2, Insightful)

      What is the net effect? Can these data be compared to model predictions?

      Let's start by an extremely rapid decline in habitat for a great many and varied species, that we cannot possibly begin to fully appreciate scientifically, let alone model with any accuracy.

      • Re: (Score:3, Insightful)

        by psyph3r (785014)
        Irrespective of humanity's perceived impact, does this not happen throughout history in a cyclical fashion? I would look at this type of activity as the main source of evolutionary change. The species that are equipped to survive the conditions will prevail.
        • by siddesu (698447) on Sunday September 27, 2009 @04:13AM (#29554531)

          It is really simple. It all depends on how much kick are you getting out of the environment as we know it.

          It is true that so far whenever cataclysms occured and species died out there was a subsequent re-population with new flora and fauna. It is also true that whenever such events have occurred, nearly all of the prevalent species have disappeared, and the subsequent re-population has taken millions of years to happen.

          So, if you really, really don't care about your species disappearing in famine and diseases and other niceties those bring then yeah, life will eventually adapt to the new equilibrium that will prevail, and there is little to worry about in the long run.

          If you are one of the neo-conservatives who want to keep living as we like it (a.k.a. tree-huggers), without disruptions and without need to die out and re-adapt, then you understand there are things that better be done sooner than later.

        • Re: (Score:3, Insightful)

          by catchblue22 (1004569)

          Irrespective of humanity's perceived impact, does this not happen throughout history in a cyclical fashion? I would look at this type of activity as the main source of evolutionary change. The species that are equipped to survive the conditions will prevail.

          A significant amount of evolution is driven by mass die offs. That is, the population of a species reduced by 99% or more. We could evolve to be a species with average height of 7.5 feet very quickly...just kill off everyone except for a few hundred p

      • by msevior (145103) on Sunday September 27, 2009 @03:40AM (#29554419)

        Sorry, I didn't mean the net effect of climate change, I meant the net amount of ice in Greenland and Antarctica. From the data provided it's not obvious that Greenland and Antarctica are losing ice. For example there are very large blue/green regions (gaining ice) that by eye could be bigger than the red regions (losing ice).

        The other question is regards climate model predictions. One of the catastrophic outcomes of climate change are large sea level rises due to ice melt in the polar regions. Presumably there are models that predict how this could occur with global warming. So the question is, do these data agree with these models?

        • by khayman80 (824400) on Sunday September 27, 2009 @03:45AM (#29554435) Homepage Journal

          One of the catastrophic outcomes of climate change are large sea level rises due to ice melt in the polar regions. Presumably there are models that predict how this could occur with global warming. So the question is, do these data agree with these models?

          The last article I read in Science [pik-potsdam.de] compared model prediction of sea level rise, and found that observations showed the sea levels rising even faster than the models predicted. Perhaps this was just short-term weather, though: more recent measurements may indicate agreement with the models.

        • by dr2chase (653338)
          Agreed, really poor choice of colors. I'm not sure what Tufte says about this particular problem -- the snap answer is to say that "zero" and a region around it should be some distinct, neutral color (white? but what about my monitor's color balance?) with clearly different colors for + and -. But you'd like to mix some sort of an area measure in, too -- if the whole continent had declined uniformly at a rate of .1 meters/annum, that would be alarming, even though .1 is well within the "cannot tell WTF c
    • by blind biker (1066130) on Sunday September 27, 2009 @02:22AM (#29554159) Journal

      Yes for Antarctica - there does, indeed, seem to be a balancing between areas with thinning and those with thickening ice. But not for Greenland, which appears to be pretty much on a dramatic thinning regimen.

    • by should_be_linear (779431) on Sunday September 27, 2009 @02:26AM (#29554169)
      if net effect was positive, that would be great surprising news. It seems, instead, situation is getting worse so quickly that we are heading towards geoengineering (desperate) solutions.
    • Re: (Score:3, Funny)

      by jamesh (87723)

      I'm with you. I'm going to wait until the sharks are swimming around my ankles here in central Victoria, Australia, before I stop pumping CO2 into the atmosphere.

      It has to be sharks too. Angry sea bass aren't going to convince me. There are plenty of non-global warming explanations for why sea bass could be swimming around my ankles, and so that alone should not be taken as hard evidence of climate change.

      And once I'm finally convinced that the climate is in fact changing, the presence of sharks swimming ar

    • Re: (Score:2, Interesting)

      by gregraven (574513)
      I, too, am curious that this story appeared the day after a story entitled, "Antarctic Ice Is Growing, Not Melting Away." http://www.news.com.au/story/0,27574,25348657-401,00.html [news.com.au]
    • by mdsolar (1045926)
      Both are contributing to sea level rise so the net effect is loss of ice. See page 3 here: http://www.unep.org/compendium2009/PDF/Ch3_compendium2009.pdf [unep.org]

      The whole report can be found here: http://www.unep.org/compendium2009/ [unep.org]
    • It seems likely to me that ice loss at an ocean boundary will cause a reduction in floating ice sheets. Those floating ice sheets act as a barrier to glacial ice flowing into the ocean. Their reduction could cause an acceleration of ice flow into the sea.

      In addition, it also seems likely to me that increases in ice in certain areas are associated with the increased moisture carrying capacity of warmer air. To snow, all you need is for the temperature to be below 32F/0C. If the warming continues, the ice

  • by n2rjt (88804) on Sunday September 27, 2009 @02:13AM (#29554121) Journal

    I see on the maps that some areas are thinning, near the coasts, and other areas are thickening.
    I wonder if that is the usual pattern, or if they are seeing something unusual.
    The article didn't mention that, as far as I could tell.

    • by Beryllium Sphere(tm) (193358) on Sunday September 27, 2009 @02:18AM (#29554141) Homepage Journal

      Qualitatively, what you'd expect from climate change is more precipitation (because there's more evaporation) and therefore thickening at high elevations where the snow stays cold, while lower warmer regions flow faster or even melt.

      • by khayman80 (824400) on Sunday September 27, 2009 @03:05AM (#29554297) Homepage Journal
        Exactly. I've described my research [slashdot.org] into Greenland's ice sheets. My most recent estimates show that Greenland as a whole is losing ~100 Gtons of ice every year, but my advisor believes my estimate is too low by a factor of 2. As you say, northern Greenland is gaining mass, but southestern Greenland is losing much more mass. Climate change is a very serious [dumbscientist.com] problem, and I'm really annoyed that health care is currently distracting the Senate from an issue that affects the future of the entire human race.
        • by BrokenHalo (565198) on Sunday September 27, 2009 @03:41AM (#29554429)
          and I'm really annoyed that health care is currently distracting the Senate from an issue that affects the future of the entire human race.

          Well, this doesn't help, but I can see why health care is the focus of attention: it is one thing the government can do something about. Climate change is a serious problem, but it is now too big to fix, since no-one has the will to adopt a policy amounting to more than "business as usual" and "let's have another toke on that big ole' oil-pipe".

          A lot of political mileage is being made of proposed emissions trading schemes, but it's too late for that. They are just accounting exercises - like pushing food around on the plate to make it look like you're eating less.

          I'm sorry if that sounds defeatist, but I'd be happy to hear an alternative. People will not change until they're forced to.
          • Re: (Score:3, Insightful)

            by khayman80 (824400)

            I've repeatedly [dumbscientist.com] argued [slashdot.org] that we need to start building as many modern nuclear fission plants as possible. Preferably pebble bed reactors, using breeder reactors and reprocessing techniques to turn the waste into useful fuel.

            And as I've explained on my homepage, I think that cap-and-trade will make coal less profitable, and nuclear power more profitable. It's a very capitalistic approach to the problem of climate change.

        • ... I'm really annoyed that health care is currently distracting the Senate ...

          Look at bigger picture. Do not be narrow minded as rest of the scientists.

          Climate change first and foremost affects humans. Having better health care would help to absorb some of the climate change effects.

          One step at a time. There is always time for the panic and apocalypse. At the moment we try to make sure that humanity as it is now would survive. And that we would be able to live on *after* surviving.

      • Re: (Score:3, Interesting)

        by MrKaos (858439)

        Qualitatively, what you'd expect from climate change is more precipitation (because there's more evaporation)

        What you are not taking into account is Global Dimming [wikipedia.org]. This phenomenon (do,do, do.do.do) blocks photons from hitting bodies of water which is what is *required* for evaporation to occur. Records of rainfalls taken in Israel has shown a decline in the amounts of rainfall as the amount of particulate matter (from pollution) increases in the atmosphere and blocks light from reaching the earth.

        This

    • Re: (Score:2, Informative)

      by Hadlock (143607)

      FTFA:

      The maps confirm that the profound ice sheet thinning of recent years stems from fast-flowing glaciers that empty into the sea.

      Which... is sort of what healthy glaciers do. Thick, healthy glaciers flow quickly due to the pressure they exert on the deeper portions, giving the lower ice under pressure more plasticity. This could be construed as abnormally healthy glacial activity, but IANAAG (i am not an artic geologist).

      I should note my liberal bias, democratic registration, and belief in glob

      • by khayman80 (824400)
        You're right. Glaciers melt all the time for reasons unconnected to emissions of fossil fuels. However, the current warming is atypical in many respects (which I've linked in another comment in this article.) Glacier melt isn't- by itself- proof of the anthropogenic origin of abrupt climate change.
        • Re: (Score:3, Informative)

          by Hadlock (143607)

          Double check your terminology there. The article specifically states glacier flow, not glacier melt in Antarctica. Glacier flow only occurs when you have lots of extra ice pushing more ice down the slope. Flow != Melt! It's way, way too cold in Antarctica for glaciers to melt anywhere on the actual landmass. Thinning ice shelf in this case is specifically due to improved glacial flow, pushing more ice out to where it can melt - in the sea.

          • by khayman80 (824400)
            Okay, that sounds reasonable. Thanks for the correction. I've heard of research showing positive feedback effects from melting glaciers lubricating the slide of the glacier into the ocean, though. Does this only happen in glaciers in more temperate regions than Greenland?
  • Does it? (Score:2, Insightful)

    by jarek (2469)

    The increased temperatures of west Antarctica are more than compensated by decreased temperatures elsewhere in Antartctica. It is especially interesting that there is so much growth inland of Greenland.

    • Re: (Score:3, Informative)

      by khayman80 (824400)
      As far as I understand it, Antarctica as a whole is warming more quickly than climatologists expected. Antarctica should be warming more slowly [realclimate.org] mainly because currently most of the land mass is in the northern hemisphere. The fact that Antarctica is warming at all is a little troubling.
      • by Troed (102527)

        Antarctica as a whole isn't warming unless you deal in dubious statistical models. The west Antarctica peninsula has been warming though, and that's where the hyperbole comes from.

        http://wattsupwiththat.com/2009/05/20/steig-et-al-antarctica-warming-paper-process-is-finally-replicated-and-dealt-a-blow-to-robustness/ [wattsupwiththat.com]

        That has likely more to do with natural shifting of the polar current around Antarctica than anything else. Changes in current location affects weather at the peninsula without affecting the rest

      • Or is less than half truths. Most of Antarctica gets colder, some of it gets warmer. By reporting on the parts that get warmer, media tries to sell disasters just because it sells better than the whole truth and nothing but the truth. West Antarctica has according to climatologists always behaved differently from the rest of Antarctica.

        Climatology news is starting too resemble a boxing match where only the strikes delivered by one of the boxers are being reported.

  • Don't matter... (Score:4, Insightful)

    by The Master Control P (655590) <ejkeever&nerdshack,com> on Sunday September 27, 2009 @02:19AM (#29554149)
    Those who demand "proof" of climate change before we do anything to fight it will find some way to ignore this. They'll keep pretending there's "no evidence" and that it's a "librul conspiracy" until it becomes undeniable (I'm betting til the dams surrounding a port city fail) because they don't believe in doing anything proactive.

    Then when the engineers say it's too late to do anything except build a 300 foot tall dam around every coastline in the world, it'll be their fault for not fixing it.
    • Re: (Score:2, Funny)

      Then when the engineers say it's too late to do anything except build a 300 foot tall dam around every coastline in the world, it'll be their fault for not fixing it.

      Wow, exaggerate much?

    • Re:Don't matter... (Score:4, Insightful)

      by icebike (68054) on Sunday September 27, 2009 @02:43AM (#29554229)

      We have been warned for years on end that coastal inundation would be the direct effect of polar melting.

      But inundation should not be a delayed effect. It should appear immediately, and in direct proportion to the melting.

      So where is it?

      • by smoker2 (750216)
        The NASA Earth Observation [nasa.gov] site has measurements of the ice coverage at the north pole. While their text speaks of massive ice loss and continuing doom, the actual graph they provide of the data shows that while the minimum ice cover is less than the average of a decade ago, there is actually more minimum ice cover than last year, and last year had more cover than the year before. Why do they not mention this at all ? Maybe the point is to mislead ? Sure they say "Though sea ice didn't melt as much in 2009
        • Re:Don't matter... (Score:4, Informative)

          by khayman80 (824400) on Sunday September 27, 2009 @06:11AM (#29554897) Homepage Journal

          The NASA Earth Observation [nasa.gov] site has measurements of the ice coverage at the north pole. While their text speaks of massive ice loss and continuing doom, the actual graph they provide of the data shows that while the minimum ice cover is less than the average of a decade ago, there is actually more minimum ice cover than last year, and last year had more cover than the year before. Why do they not mention this at all ? Maybe the point is to mislead?

          Yes, 2008 and 2009 had smaller ice extent minima [uaf.edu] than 2007. But the point is that climate models had previously predicted [demon.co.uk] larger ice extent minima than were observed in 2007. So the last several years tend to confirm that the previous measurements were due to short-term weather variability rather than a flaw in the climate models.

          If they were to publish the proper figures for 1979 to 2000 instead of just a vague average, we could maybe see whether there is a regular fluctuation, instead of guessing that the decline has been constant.

          Ask, and you shall receive [uiuc.edu]. No serious scientist is actually "guessing" that the decline has been constant, and no climate model that I'm aware of makes that prediction. Short term variability is expected, but the data shows a clear downward trend over the last 30 years.

        • With regular fluctuations we could be nearing a peak for ice cover. And this would be the lowest local max we've had in 1000years for all I know... I do know however that, using yearly data in such a manner 'hey there is more ice this month therefore global warming is a sham' is also dangerous. I have seen these types of arguements pop up in this subject fairly often. I think scientists are internally careful about these sorts of things but have lost any shred of trust they had for the public.
      • Re: (Score:3, Informative)

        by blind biker (1066130)

        We have been warned for years on end that coastal inundation would be the direct effect of polar melting.

        But inundation should not be a delayed effect. It should appear immediately, and in direct proportion to the melting.

        So where is it?

        Two South Pacific islands have disappeared beneath the waves, as climate change raises sea levels to new heights. [bbc.co.uk]

        Tuvalu, soon to be no more. [earthtimes.org]

        World's deltas subsiding, says study. [google.com]

  • by retech (1228598) on Sunday September 27, 2009 @03:24AM (#29554357)
    I thought carbon credits would have someone parked on the poles with a couple of ice making machines (perhaps like they use in a hotel but not as loud) and they'd be scooping fresh ice out to keep it topped off... why is this not happening? Have we been lied to? Where did all that carbon credit money go to? Just when I thought for sure I could sit in my apt and do something really fucking meaningful from a distance to help save all those future generations by buying offset credit every time I got on WOW and played for two days... this just has destroyed my entire weekend and trust in humanity.
  • by sl149q (1537343)

    Another POV... http://network.nationalpost.com/np/blogs/fpcomment/archive/2009/09/25/lawrence-solomon-hot-and-cold.aspx [nationalpost.com]

    He points to a National Geographic report saying the opposite.

    • Re: (Score:2, Informative)

      by hotdiggity (987032)
      Your link is talking about sea ice. Sea ice changes year over year according to local weather trends, and is just frozen sea water. Hamish's research is regarding ice sheets. The amount of ice we're talking about is a few scales of magnitude bigger, indicating more profound trends, and can affect sea level. Sea ice doesn't.
      • Re: (Score:3, Insightful)

        by smoker2 (750216)
        So we can ignore data if it suits your argument ? Sea ice is formed from and floats in the sea (duh). Global warming causes the oceans to warm - true or false ? So more sea ice can not mean a warmer ocean can it ?

        Conflicting evidence must be resolved before you discard data as worthless. This is a closed system. You may not ignore evidence that contradicts your point of view. While I know The Day After Tomorrow was horse shit, the underlying theory is not. Warming oceans cause changes in currents that circ
        • by khayman80 (824400)

          So we can ignore data if it suits your argument ? Sea ice is formed from and floats in the sea (duh). Global warming causes the oceans to warm - true or false ? So more sea ice can not mean a warmer ocean can it ?

          I read that article, and wondered why the authors missed the crucial part of the story. Yes, 2008 and 2009 had smaller ice extent minima [uaf.edu] than 2007. But the point is that climate models had previously predicted [demon.co.uk] larger ice extent minima than were observed in 2007. So the last several years tend to co

        • The amount of ice globally is quickly reducing (including sea ice). There will be variations abound, but the fact is that the global total is shrinking rapidly is quite disconcerting. I think that was GP's point.
    • But I want NPOV!

  • by Budenny (888916) on Sunday September 27, 2009 @11:26AM (#29557227)

    The question is, over what time period are we seeing rises and falls in coverage? We have no proper data before the satellite age. So all we know is that there has been recent shrinkage. We have however no idea what the standard deviation is of gains and shrinkages over a period of centuries or millenia, so we have no idea whether we are looking at an event close to the mean or one that is several standard deviations away from it.

    At this point people usually ridicule one for not being prepared to take action until there is proof, which is usually projected as being some natural disaster like New Orleans.

    The argument is mistaken. It is quite reasonable to wait for proof, because 'doing things' in the absence of proof is a risky and expensive business. It could have quite dramatic and unexpected side effects depending on what the situation really is.

    It would enormously help us figure this thing out if all the climate scientists would just publish their raw data and algorithms. That way we could at least verify their work so far. The ones that need to publish? Well, just about all of them. They supposedly have evidence that the present warming is a very rare event, but they decline to publish it. They just publish studies based on it, summaries of it, processed forms of it. We need this data, and we need the code that was applied to it.

    Without that, its not science, its arm waving. There is probably nothing more important than to establish the climatic history of the last 2,000 years, and if we could establish ice coverage and density in some way, that too. Without the scientists publishing, I do not see how we take this debate any further. It is, to say the least, curious that the main workers in the field, the ones who find the present trend most alarming, are the ones who refuse to reveal the data that would prove them right.

    Where, for instance, is Mann's algorithm, the one he refused to supply to the Wegman Committee? Where is the data underlying the HADCRU series? Where is Thompson's ice core data?

    If we cannot see it, how do we even know it exists?

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