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Arctic Sea Level Falling? 368

Posted by timothy from the hollow-earth-explains-all dept.
HRH King Lerxst with a link to BBC News' report that "Arctic sea level has been falling by a little over 2mm a year — a movement that sets the region against the global trend of rising waters. ... It is well known that the world's oceans do not share a uniform height; but even so, the scientists are somewhat puzzled by their results."
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Arctic Sea Level Falling? More

Arctic Sea Level Falling?

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  • Could Be A Number Of Things (Score:4, Insightful)

    by eldavojohn ( 898314 ) * <eldavojohn@noSpAM.gmail.com> on Thursday June 15, 2006 @10:23AM (#15539719) Journal
    "I think it's a true statement to say the Arctic Ocean is the least well understood body of water out there" -- Dr Seymour Laxon, UCL
    I think that's because few other bodies of water have a massive chunk of ice in them ... with many more smaller chunks floating around.

    Funny things happen when you have solid H2O in liquid H2O that, on a large scale, are probably not well understood. I'm not a physicist but you have heat dissipation as Newton's Law of Cooling goes into effect and a multitude of climate issues. I can speculate on a few things:
    • As the water becomes warmer, it is more prone to evaporation on the surface from the sun. Previously, less water would evaporate and keep the water levels slightly higher but now the difference in temperature at the surface is less making the water more easily transferred into a vapor.
    • Gravity pulls down on the free floating icebergs and it displaces the water. These icebergs are shrinking or being reduced greatly so the water height in the vicinity lowers slightly while the water levels around the world rise slightly.
    • The tides are becoming stronger and as the amount of water on the surface of earth increases, so does the effect of the moon on it. The moon pulls least on water at the caps and even more so on water near the equator.
    • Some force (moon, internal gravity, spinning of the earth, sun, etc.) is causing the water to accumulate at the equator which in turn reduces the water at the poles.
    Like I said, this is pure speculation and I haven't thought out in advance the above propositions. But I'm going to speculate that there's an unknown effect that occurs when massive bodies of ice are half submerged in water on a planet. The basis of this effect is probably known in physical and chemical fields of science but we just haven't put them together to figure it out. Hopefully we can figure it out as these "discoveries" are oftentimes the foundation for more work and more discoveries that benefit mankind. Translation: curiosity spurs innovation.

    If there's one thing that Slashdot is good for, though, it's testing half cooked theories! My fellow colleagues, I welcome you to point out the scientific flaws in my above hypotheses!

    • As the water becomes warmer, it is more prone to evaporation on the surface from the sun. Previously, less water would evaporate and keep the water levels slightly higher but now the difference in temperature at the surface is less making the water more easily transferred into a vapor.
      Possible, but this would then result in more cloud cover. While this may be happening, I haven't seen any reports saying its happening. Of course more cloud cover would result in less light hitting the surface and thus re

    • Isostatic rebound (Score:4, Informative)

      by amightywind ( 691887 ) on Thursday June 15, 2006 @10:39AM (#15539852) Journal

      Nice speculation. But since the end last ice age most of the coastlines surrounding the Arctic Ocean have undergone isostatic rebound [montana.edu]. Most of these areas were highly glaciated and heavily loaded with ice. Once the ice was rapidly removed the land maintained bouyant equilibrium by rising. Apparent sea levels have been falling in these areas for 1000's of years. The only question is how long it will continue and how isostacy and sea level rise interrelate in different areas.

      • That was my first thought as well, but the high water mark on land isn't what is being measured from satelite. Rebound raises the land level, and shouldn't (greatly) affect the sea level.

        An interesting item is that the global sea level is rising.

        Of course, the real answer is that the water up there is cold, and cold water makes things shrink ;-)

      • i just want to know their tolerances/error. 2mm? wtf?

      • Re:Isostatic rebound (Score:3, Interesting)

        by Vreejack ( 68778 )
        I would hope they had taken isostatic rebound into account. Actually what puzzles me is how they measured sea level. Are they comparing it to the earth's geode? For those who never heard this before, the geode is an imaginary surface that represents where sea level would be if water were magically allowed to flow without viscosity underneath the earth's land mass. It is not a sphere or even a spheroid but follows the local gravity variations so that it actually rises underneath mountains and dips over

    • Re:Could Be A Number Of Things (Score:4, Insightful)

      by Instine ( 963303 ) on Thursday June 15, 2006 @01:06PM (#15541195)
      I am a physicist, and this is the closest you got to the most likely scenario (IMO).

      "Some force (moon, internal gravity, spinning of the earth, sun, etc.) is causing the water to accumulate at the equator which in turn reduces the water at the poles. "

      Not so much a force, but a lessening of one. The centripetal force of the spinning earth makes the oceans deeper at the equator. The viscosity of the water counters this. The viscosity is lessened with heat. Bingo!
    • Since we are pulling ideas out of our asses...

      Actually it is just a geodesy affect. The satellite is drifing 2mm away from the earth and back every time it passes over the artic.
    • Everyone here seems to have forgotten one of the oddest priciples of H2O. When it freezes, it expands, when it melts it contracts. Simple.

  • First guess (Score:2, Interesting)

    by Nuffsaid ( 855987 )
    May be connected to a slowdown of the Gulf Stream?

    • Re:First guess (Score:2, Interesting)

      by ajpr ( 921401 )
      I think in a round about way, yes.

      Freshwater ice is less dense than fresh water (which is less dense than salt water). As the ice melts it occupies a smaller volume (which is of course why ice floats). The difference is a fairly significant percentage and may explain the sea level drop. This in turn is evidence of large amounts of fresh water forming in the arctic and this leads to the theory behind slowing the gulf stream down.

      However most ice on oceans is from seawater: "Sea ice, formed in saltwater, a

  • What? (Score:5, Funny)

    by MrSquirrel ( 976630 ) on Thursday June 15, 2006 @10:27AM (#15539744)
    ...What?... I was THIRSTY, okay?
    • Hmm, that was salt water. You should be dead in 3....2....1....

  • Of course... (Score:3, Insightful)

    by evileyetmc ( 977519 ) on Thursday June 15, 2006 @10:30AM (#15539769)
    There has been periodic change in water levels for thousands, if not millions of years. While it may seem alarming, and probably does have a large effect on our climate, it is not just CO2 emissions to blame. I'm sure the tectonic plates shifting (I'm no geologist) and various other natural phenomena contribute a significant amount to the change in the earth's water level, just like they have for a long time before we were around.

    • OK, that's a reasonable opinion to hold. But why would we accept your unsubstantiated opinion against the consensus opinion of people who do not about climate?

  • Not a surprise (Score:2, Funny)

    by Anonymous Coward
    The arctic icepack is melting at an accelerated rate, due to global warming. Once the ice is gone, it is no longer displacing so much water, and so sea levels drop.
  • Could it also mean that warmer = more evaporation = more water vapor in the air = more heat trapped and so on ...

    • Re:Global warming? (Score:3, Informative)

      by shotfeel ( 235240 )
      No, more water vapor = more clouds = more light reflectd -> cooling

    • "Global Warming" is total bunk (Score:5, Insightful)

      by WebCowboy ( 196209 ) on Thursday June 15, 2006 @02:02PM (#15541825)
      warmer = more evaporation = more water vapor in the air = more heat trapped and so on

      It means nothing of the sort my friend. In fact as scientists analyse global climate, they seem to be slowly, subtlely distancing themselves from the theory/term of "Global Warming". Have you noticed that authorities on the subject--even the most ardent supporters of things like the Kyoto initiative--now almost NEVER use the term anymore? The correct term is "Global CLIMATE CHANGE" because EVERYONE agrees that the earth is not universally warming up (some areas are, and others are getting cooler), and they aren't even convinced anymore that the AVERAGE gloabl temperature will continue to steadily rise. What they DO agree upon is that the climate is CHANGING--they point to evidence of changing weather patterns and more "extreme weather"--we'll get more Katrina's in the Gulf of Mexico and huge, freezing blizzards in maritime Canada and expanding deserts in Africa. The general consensus is still that CO2 from human activity exacerbates the problem--it's just that scientists now cover their butts with more general terms like "climate change" because truthfully, NOBODY has a handle on what exactly is going to happen.

      The situation might go as you state, but there are a number or drastically different predictions as well:

      warmer -> more evapouration -> more cloud formation -> sunlight blocked -> cooler

      or ... ... ... -> more cloud formation -> wetter weather -> more vegitation in once barren areas -> more CO2 uptake from vegitation -> less GHG and more O2

      or

      warmer -> melting polar ice -> lower ocean temperatures -> shifting weather patterns -> more "even" climate (warmer & wetter towards poles, cooler in the equatorial region)

      NOBODY knows what will REALLY happen--it is all guesswork (albeit really educated guesswork). Although those who say human activity/CO2 emissions have no notable effect on the planet are generally dismissed as crackpots (and rightly so), the scientific community is finally acknowleging--at least a bit--that they don't know the ultimate effect, which is significant becasue high-profile research organisations really hate to admit they don't know something (almost as much as they hate admitting they're wrong). And here is one to cheer you up--there is a growing contingent of scientists that say "yes, human activity has altered our climate, but the can is open and the worms have long since escaped--we are past the point of fixing things".
       
      • They are changing their terminology simply because the general public did not get what they were saying. People hear "warming" and they think of spring and butterflies--sounds nice doesn't it?

        But what it means in terms of climate is related to the true scientific meaning of the term temperature--a measure of the total energy in a system. "Warming" simply means that more and more energy is being stored by the system. Think of a fly wheel being spun up faster and faster.

        EVERYONE agrees that the earth is not u

  • Global Dimming vs Global Warming (Score:3, Informative)

    by wklam ( 174349 ) on Thursday June 15, 2006 @10:50AM (#15539956)
    http://en.wikipedia.org/wiki/Global_dimming [wikipedia.org] [Wikipedia on Global Dimming]

    Quote: Some scientists now consider that the effects of global dimming have masked the effect of global warming to some extent and that resolving global dimming may therefore lead to increases in predictions of future temperature rise.

  • Every physicsts know that when a spinning orb gets bulged out, the rotation slows down, only to spin faster again.... ad infinitium (almost).

    This is normal Earth rotational speed oscillation on an eon scale.

    Move along, nothing new to see here.
  • I wouldn't take seriously any explanation posted here. I've read through a few of them, and although I myself am not a climatologists, they do strike me as being scientific-sounding rationalisations of an existing opinion.

    Climate change is a kind of political topic, and this means that everyone who has a political opinion pretends to be an expert on the subject.

  • The Wright answer (Score:5, Funny)

    by Ken Hall ( 40554 ) on Thursday June 15, 2006 @11:31AM (#15540325)
    Maybe global warming is causing an increase in the sponge population.

  • The Precautionary Principle (Score:3, Insightful)

    by Frekja ( 982708 ) on Thursday June 15, 2006 @11:43AM (#15540434)
    One thing I haven't seen mentioned recently in the comments on Slashdot is the idea of the Precautionary Principle (http://www.unu.edu/unupress/unupbooks/80841e/8084 1E0o.htm#12.%20The%20precaution%20principle/ [unu.edu]. By its very nature, good science is uncertain- its investigations rarely produce evidence that points in only one direction, and the whole point of the scientific method is to avoid coming to dogmatic, unjustified beliefs.

    This produces problems when science and politics come together, because of the way science is treated by popular culture and popular politicians. Essentially, science is popularly viewed and portrayed as being a source of certainty. This is why the extremely small number of global warming naysayers always are referred to as scientists (irrespective of whether their credentials are respected or relevant). It creates the illusion that "science" has yet to arrive at its intended goal: absolute certainty. But as any good scientist will tell you, scientific truth is always provisional.

    Thus, the trouble with doing something about global warming is that there is a disjunction between the sort of certainty (absolute) that politicians facing re-election and pressure groups want before acting, and the sort of certainty (provisional, always subject to revision) that scientists can, in good faith and following the strict methodology of science, give. Enter the precaution principle, which basically states that if you have a reasonably likely possibility of really bad future outcomes, you should try to do something about it, even if it's possible those outcomes don't come to pass. To me, global warming fits this scenario.
    • > Thus, the trouble with doing something about global warming is that there is a disjunction between the sort of certainty (absolute) that politicians facing re-election and pressure groups want before acting, and

      Politicians don't like absolute certainty. They merely want to be able to construct the appearance of absolute certainty when it suits their agenda, and the appearance of absolute doubt when that suits their agenda.
    • Enter the precaution principle, which basically states that if you have a reasonably likely possibility of really bad future outcomes, you should try to do something about it, even if it's possible those outcomes don't come to pass. To me, global warming fits this scenario.

      To me, the typical proposals that are bandied about also fit that scenario. To wit, proposing that the western economies/cultures most able to continue their existing work in making more efficient use of energy "fix" the problem by cri
    • To me, global warming fits this scenario.

      You missed a key element, though, which is that it only makes sense to do something if: (a) your actions are likely to have a positive (rather than no or negative) effect on the problem and (b) the benefits outweigh the costs. Now, I'm not convinced that global warming is substantially more likely to have negative effects than positive ones, and I'm even less convinced that, if it were demonstrably more likely to have negative effects, we would feasibly be able to

    • "The precautionary principle, a phrase first used in English circa 1988, is the idea that if the consequences of an action are unknown, but are judged to have some potential for major or irreversible negative consequences, then it is better to avoid that action"

      Did humans, when first inventing the automobile, use the precautionary principle? No, and we are better off with them. Think ambulances.

      Did humans, when inventing computers, use the precautionary principle? No, and we are better off with them. Sh

  • The Chicken Little Theory (Score:4, Funny)

    by Atomm ( 945911 ) on Thursday June 15, 2006 @12:33PM (#15540934) Homepage
    The artic ocean has not fallen 2mm. The sky has fallen 2mm. This gives you the impression the ocean is down 2mm. ;-)

  • This is speculation on my part, but I know that most arid countries have invested very heavily in large reverse osmosis plants that provide a significant portion of their fresh drinking water (anyone have stats?).

    As the global population shoots up, and people continue trying to find ways to make inhabitable land habitable, I only see this trend increasing.

    Is it possible that we could end up sucking up enough water out of the oceans and redistributing it that we could change not ocean levels?

    At first thought
  • Bottled water, pop, beer, juice. Blame Coke, Pepsi and all the other product bottlers. All the missing water is sitting inside of glass or plastic bottles.

    If that isn't the answer, than I'm sure Mayor Adam West's research will not have been in vain... (Family Guy reference for those not in the know)

  • Blame the dolphin's (Score:3, Funny)

    by guruevi ( 827432 ) on Thursday June 15, 2006 @01:15PM (#15541286)
    Good bye and thanks for all the fish, now that all the mass of them darn dolphin's are gone, the water dropped by 2mm. Easy explanation.

    The end is near - I knew it.
    • I think you mean "...now that all the volume of them darn dolphins...".

      Remember, lead dolphins and Styrofoam dolphins displace the same amount of water.


      Nonetheless, your Hitchhikers' Guide reference is appreciated.
  • Frozen water expands, taking up more room. When the ice melts, the volume it takes up reduces, lowering the sea level.

    • Frozen water expands, taking up more room. When the ice melts, the volume it takes up reduces, lowering the sea level.

      Frozen water expands, taking up more room, but also lowering the density. Ice on land that melts goes into the sea, theoretically raising the water level. Floating ice melts, becoming more dense, thus the part that was above the water now displaces space as well, resulting in no net change in the water level. So a positive amount of displacement from runoff added to no change in displacem

  • The drop in ocean level is caused by global warming -- the water evaporated to form huge clouds of smug [wikipedia.org]!

    --Rob

  • The Physics (Score:2, Informative)

    by remnant_x ( 982760 )
    By no means am I an expert in the field, but I do have a firm head on my shoulders, and am confused by the lack of any "discussion" section in the BBC report. So here is a part of mine. Although it is common to say that the top of a continuous body of water is all at the same elevation (a fact surveyers use extensevly to reduce costs), that statement is wrong. The tops of water bodies follow an equipotential surface. This means that each top point will have the same potential energy. In small surfaces,
  • Ok, so, they are using a radar to measure distances on the order of 800KM. Add to that they are taking measurements of a surface which has lots of irregularity, 10 foot waves are not at all unusual on that stretch of ocean. Add to the mix this little detail that the transmitter and reciever for this signal are doddling along at orbital velocity. Now toss in a few thousand corrections for things like temperature etc. When you are all said and done, draw a conclusion accurate to tenths (or even hundredths

  • It's all relative. (Score:3, Interesting)

    by 955301 ( 209856 ) on Thursday June 15, 2006 @03:00PM (#15542432) Journal
    I can make the entire thing make sense in a matter of seconds!

    Change

    Arctic sea level has been falling by a little over 2mm a year - a movement that sets the region against the global trend of rising waters. A Dutch-UK team made the discovery after analysing radar altimetry data gathered by Europe's ERS-2 satellite.

    to

    Europe's ERS-2 satellite has been falling by a little over 2mm a year. A Dutch-UK team made the discovery after analysing radar altimetry data gathered over the Arctic sea level.

  • Not really a surprise (Score:3, Interesting)

    by dublin ( 31215 ) on Thursday June 15, 2006 @06:03PM (#15544276) Homepage
    This shouldn't really be a surprise - after all, it's been known for several years that the water level of the oceans is going down, due to the "leaky seas" phenomenon. See New Scientist article from a few years ago at http://www.newscientist.com/article/mg16322030.200 .html [newscientist.com] (used to be free, but no longer), or a CNN summary at the time: http://www.cnn.com/NATURE/9909/17/leaky.seas.enn/i ndex.html [cnn.com]

    No one knows why - forming mineral hydrates, some other form of leaking into the earth itself, or global cooling - it's all speculation right now, just like global warming. The truth: The world is a complex place and we're not even close to understanding it.

    BTW: Remember when "all the world's climate experts" warned of global cooling and an impending ice age only around 30 years ago? (Which would, of course, require many of the same environmental policy changes wanted by the global warming crowd now.) Those who forget history are doomed to repeat it.

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