Polar Ice

Discussion in 'Earth Science' started by Orleander, Jul 13, 2007.

  1. Orleander OH JOY!!!! Valued Senior Member

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    If the polar ice caps melted, would earth's axis rotation change?
    And if it did change it, would the melted caps affect us more than the axis change or vice versa?
     
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  3. James R Just this guy, you know? Staff Member

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    The axis of rotation wouldn't change, but the Earth's rotation would slow slightly.
     
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  5. Orleander OH JOY!!!! Valued Senior Member

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    why would it slow? Wouldn't the same amount of water be on the planet, just in a different area?
     
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  7. River Ape Valued Senior Member

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    Well, yes. Eversoeversoeversoseverso slightly!
    But why did you duck explaining the Conservation of Angular Momentum?
     
  8. Fraggle Rocker Staff Member

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    When the mass of a rotating body is redistributed inward--as when frozen water melts and occupies less volume, not to mention glaciers moving downhill as they become water--doesn't that change in the moment of inertia actually increase the speed of rotation, in order to conserve angular momentum?
     
  9. Oli Heute der Enteteich... Registered Senior Member

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    Yup but the "water" would be moving from the poles (near the axis) to the oceans - spread sort of round the equator (or at least further away from the axis).
    So it would cause slowing.
     
  10. James R Just this guy, you know? Staff Member

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    Nobody asked about that.

    If you want to explain it, go ahead.
     
  11. James R Just this guy, you know? Staff Member

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    Fraggle:

    You're right, but that I think the major effect of melting the ice caps - the land ice, not the sea ice - would be to raise overall sea levels, and effectively get more water at the equator and less at the polls. Since the Earth is not spherical, more water at the equator means an increase in the moment of inertia of the Earth.
     
  12. Fraggle Rocker Staff Member

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    Two great minds with the same explanation. Thanks! I never got far enough in physics to calculate the moment of inertia of a three-dimensional object. Obviously it only rotates in two dimensions. Silly me.
     
  13. River Ape Valued Senior Member

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    I had half a mind that was what you were thinking, James R;
    so that makes two and a half great minds!
     
  14. James R Just this guy, you know? Staff Member

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    Ugh! I just noticed the numerous spelling mistakes and typos in my reply to you, Fraggle. I hope that as our resident language expert you're not too offended.

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  15. Fraggle Rocker Staff Member

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    ??? I didn't see any. Anyway, I'm not an expert, just a moderator.

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  16. Andre Registered Senior Member

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    Other effects are:

    Even a slightly higher sea level increase at the equator because of local gravity changes: The ice masses at the pole attract water away from the equator.

    Sea levels would still increase millenia after melting with the isostatic rebounce of the previously glaciated area causing subsidence elsewhere

    But then again Antarctica and Greenland ice sheets survived the Holocene thermal optimum some 9000-6000 years ago, with several degrees warmer than today, so why would we expect something different now?
     
  17. Read-Only Valued Senior Member

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    Because both are melting now at rates never before recorded - based on ice core samples. That's been in the news for quite some time.
     
  18. Andre Registered Senior Member

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    really?

    So,
    this (pp 18-19) is all peer reviewed garbage then?

     
  19. Andre Registered Senior Member

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    Shall we quantify that a bit:

    http://www.sgg.whu.edu.cn/icct/html/icct_ppt/S1/Ramillien_guillaume____third.pdf

    (large presentation)

    For the narrow bandwidths:

    On slide 15: contribution of ice sheets to sea level change per year according to the satellites of GRACE:

    The last slide:

    Seem to miss a conclusion that both are melting now at rates never before recorded
     
  20. Read-Only Valued Senior Member

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    Really???

    Simply do a Google search on "ice sheets melting" and you'll get over 1.5 million hits. Several may be duplicates, of course, but there's still tons of information there that refutes your claim.
     
  21. iceaura Valued Senior Member

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    Not that simple. That appears to have been solar irradiance warming, with a different pattern - greater warming during the day, less at night, greater in the summer, lesser in the winter, greater at low latitudes, lesser at high, etc.

    Greenhouse gas warming might have much different effects on an ice sheet than that pattern, regardless of the numerical average temperature over a year.
     
  22. Andre Registered Senior Member

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    Really?? well ok then, I'll tell those scientists that they should not have spent billions on develloping satellite techniques to measure those things with great accuracy. So, what they actually measure is irrelevant because everybody else knows exactly what is going on. Just ask google.

    It's called preconceptual science:

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  23. Read-Only Valued Senior Member

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    Good. Feel perfectly free to tell them - they're waiting to hear from you.
     

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