A Note: Global Warming Threads

Discussion in 'Earth Science' started by Tristan, Aug 27, 2004.

  1. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    Never mind about 20 billion, how about >3 billion now living in China, India and other parts of Asia and Africa?

    Would you be happy to see them consuming oil at the US per capita rate (and the > $100 / gallon price of gasoline that implies, etc.) ?
     
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  3. Trippy ALEA IACTA EST Staff Member

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    Only the science behind the Greenhouse Effect has its roots buried deep in accepted physics (Simple Harmonic Motion).

    If one accepts Simple Harmonic Motion, and if one accepts black body radiation, then one must accept the greenhouse effect, and one must also accept that changing atmospheric chemistry must change climate, and the only debate can really be 'To what extent'.
     
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  5. iceaura Valued Senior Member

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    You would be the first to post any such studies on this forum. So far we've seen irrelevancies and deflections, strawman arguments, and a lot of simple errors of logic (for example: "the globe has warmed in the past from other causes, therefore it will not warm now from CO2 boosting").

    You have no competition. Feel free.
     
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  7. paulfr Registered Senior Member

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    Supporting Evidence ??

    These are rather strong assertions that lack any trace of supporting evidence.
    Where did you find or calculate [or dream up ?] the figure 1 to 2 degrees as a tripping point to positive feedback ??

    Methane concentrations are less than a tenth of CO2 in the atmosphere, which makes its contribution [if your scenario holds ] about equal to CO2 contribution.
    And CO2 is mearly .038 % of the atmosphere. Gonna need a lot of gain from somewhere to have the Bode Plot have unity with phase greater than 180 deg or
    the Root Locus to make it to the RHP.

    100 meter sea level rise ?? You sound like an alarmist.

    Remember that man made Carbon additions to the atmosphere are less than 10% of the natural additions due to organic decay and ocean evaporation.
    It is hard to make a case for Anthropogenic GW with these facts.
     
  8. John99 Banned Banned

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    22,046
    its a consequence of knowing too much but not enough. my guess is that perceptions will level off in a century or so.
     
  9. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    I did not assert that. I first noted that the full problem is very complex. Few studies even include the possible release of CH4 stored in methane hydrates on the continental shelves mainly (or if in the deep sea, they will remain stable much longer as most of the deep ocean is always less than 10 degrees C)

    As there is more energy stored in these CH4 hydrates than ALL the fossil fuel yet burned, there is some unknown tripping point where the system goes unstable with positive feedback. As CH4 is a much stronger GHG than CO2, even half of the hydrates CH4 dumped into the atmosphere in a decade or two would have a good chance to convert the Earth into its other stable state: A slightly cooler version of Venus. This would not completely be achieved for a very long time as the heat capacity of the oceans is very large. I.e. it would take a long time for the last drop of liquid water to become atmospheric steam. However, that is of little concern, as Earth would be sterile long before the oceans begin to boil.

    I did not calculate 1 or 2 degrees, but most climate models do suggest even that small change would make significant changes. So I only noted in view of the complexity of the problem and the uncertainty as to how far from the "tipping point" we now are that PERHAPS 1 or 2 degrees could initiate the release of the CH4 of the hydrates at a rate which exceeds it removal (by oxidation processes I think) If that should be the case, then eventually the oceans will boil away.

    Many take comfort in the fact that the Earth has been more than 2 degrees warmer in the past. I.e. conclude there is no great danger, but only some readjustments, needed to survive even 3 degrees hotter Earth. IMHO, this is an invalid argument. All prior warming changes were at a very slow rate. (< 1degree C in more than 10,000 years I would guess.) As the methane of hydrates was slowly released during this warming, they were destroyed by atmospheric process. I would even guess that the higher temperatures speeded their rate of destruction so possibly the atmospheric concentration of CH4, when the Earth was 3 degrees warmer, was even smaller than it is today and did not significantly increase the global warming - certainly did not make a positive feedback to push Earth over a tipping point. (Proof: Earth is not now in the hotter stable state, still has liquid water, etc.)

    SUMMARY: I am not saying Earth is about to start the runaway process which converts it into the hot stable state. Only that this process very probably does exist and we do not know if we are close to the tipping point or not. I.e. PERHAPS 1 or 2 degrees rise, RAPIDLY ACHIEVED, due to man's unprecedented rate of CO2 release may sent Earth on an irreversible path to the hot stable state. The problem is complex, we simply do not know.

    I am reminded of Christ's words from the cross:
    "God forgive them as they know not what they do."
     
    Last edited by a moderator: Apr 27, 2009
  10. Vince123 Registered Member

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    2
    Global warming is just a conspiracy cause nobody was buying solar panels and windmills. It's all just a big lie to increase sales.
     
  11. Trippy ALEA IACTA EST Staff Member

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    Try doing some physics.
     
  12. paulfr Registered Senior Member

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    Ideal Gas Law

    Perhaps you are not familiar with the Ideal Gas Law, pV = nRT.
    Increase in temperature will result in an increase in pressure or volume or both.

    Your balloon analogy is flawed because the balloon has atmospheric pressure to confine it. The edge of our atmosphere is vacuum and presents no such constraint.

    Since the GHGs [CO2, H2O vapor, CH4, etc ] capture the energy and reflect some back to Earth, the atmosphere is what first heats up.

    So why does the Ideal Gas Law not apply ?

    Can anyone explain why a simple expansion which will cool the gases [ which allows negaitve feedback and stabilization of the temperature] can not occur ?
     
  13. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    23,198
    It occurs all the time. Why air at the mountain top is cooler than in the valley below. Why Death Valley (below sea lever) is hotter that other areas.

    As a large air mass rises, there is little heat removed from it as it expands. I.e. it "adiabatically" cools. If it is moist air, this cooling may cause water vapor to condense, which is a source of internal heating (540 Cal/ gm condensed, if memory serve me correctly). Thus if it is a big chunk of moist air rising in drier air that only adiabatically cooled, it will continue rising higher. Eventually it may get up to where the surrounding air is below freezing and hail will start to form. It is easy to watch this process form "thunder head" clouds. Process is closely related to the Taylor instability, or could even be considered and example of it.
     
    Last edited by a moderator: Apr 29, 2009
  14. iceaura Valued Senior Member

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    24,279
    The only horsebeating so far has been crap like this:
    Again: feel free.
     
  15. Buffalo Roam Registered Senior Member

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    The explane the Milankovitch Cycles, and why they are not a far more likely source for global warming and cooling than man made CO2

    http://www.gly.fsu.edu/~kish/dynamic/global/LAS.htm

    Orbital shape (eccentricity)

    Axial tilt (obliquity)

    Precession (axial rotation)

    The external controls of the Earth's climate can be summed up in the list below:
    External Factor How Climate is Affected

    Milankovitch Cycle The amount of solar radiation
    *Eccentricity of orbit entering atmosphere varies
    *Obliquity of axis with change of Earth's position
    *Precession of axis

    Total Solar Output The amount of solar radiation
    leaving the sun varies

    Thomas (2002) states,

    "The eccentricity influences seasonal differences: when the Earth is closest to the sun, it gets more solar radiation. If this occurs during the winter, the winter is less severe.

    If a hemisphere has its summer while closest to the sun, summers are relatively warm."

    Currently the difference between closest approach to the Sun (perihelion) and furthest distance (aphelion) is only 3.4% (5.1 million km). This difference is equivalent to about a 6.8% change in incoming solar radiation. Perihelion presently occurs around January 3, while aphelion is around July 4. When the orbit is at its most elliptical, the amount of solar radiation at perihelion is about 23% greater than at aphelion. This difference is roughly 4 times the value of the eccentricity.

    So why should we accept Man Made Global Warming as fact?
     
  16. iceaura Valued Senior Member

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    24,279
    Really, Dr Mabuse, that's what we've been getting - piles of it. Don't let this sentiment
    slow you for a second.
     
  17. Trippy ALEA IACTA EST Staff Member

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    Because all too often, people loose site of the fact that the physics of global warming is well grounded and 'proven'.
    http://www.sciforums.com/showthread.php?t=92369
    If you accept accept Simple Harmonic Motion, and the Stefan Boltzman law, then you must accept that atmospheric chemistry must play a role in climate.
    If you accept that atmospheric chemistry must play a role in climate, then you must also accept that altering atmospheric chemistry must alter climate, then the only debate can really be around how much?

    At this point, I find it interesting to note that all climate models fail miserably to predict (or perhaps more correctly retrodict) the climate over the last 100 years or so when considering only solar forcings.

    Or are you suggesting that the composition of the blanket that helps keep us warm has no influence over how warm we're kept?
     
  18. KernNeart Registered Senior Member

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    as i read this thread a few things come to mind..but im afraid to say them because i know that people will rip me apart.. speaking of.. i dont think the point of a thread is to intimidate others.. its to spread ideas.
     
  19. guthrie paradox generator Registered Senior Member

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    4,089
    BEcause....
    We can plot the Milankovitch cycles and work them out for tens of thousands and millions of years. Oddly enough they do indeed have some effect. But there is no evidence whatsoever that they are responsible for the current comparatively rapid warming.
    On the other hand we have plenty of evidence for AGW, perhaps you would like to hear of some of it?
     
  20. Buffalo Roam Registered Senior Member

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    We can't? since when? :roflmao:
     
  21. SkinWalker Archaeology / Anthropology Moderator

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    5,874
    Where, precisely, did the previous poster use or imply "can't" or "cannot"?
     
  22. guthrie paradox generator Registered Senior Member

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    4,089
    Just read my post again. Despite having posted it after night shift, it still reads ok to me, so maybe Buffalo can explain?
     
  23. guthrie paradox generator Registered Senior Member

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