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A climate test

  1. Mar 11, 2009 #1
    Last year saw several publications about the climate of the past. I call to the stand, Mann et al 2008 about a reconstruction of the global temperatures in the last 2000 years and Van Hoof et al 2008 about a CO2 reconstruction based on stomata variation, reacting on CO2 levels in the period 1000-1500 AD.

    This is how they correlate:

    2505ybt.jpg

    Who would want to conclude that the CO2 concentration controls the temperature?
     
  2. jcsd
  3. Mar 11, 2009 #2
    Ah reality wrong, assumptions right.

    Not the point. The point is that there was independent variation both in CO2 and temperature. Mind that the enormous dynamic flux of CO2 between atmosphere and with the ocean dwarfs everything else. Some changes there in flows could have a big impact on that balance.

    http://www.uwsp.edu/geo/faculty/ritter/geog101/textbook/earth_system/carbon_cycle_NASA.jpg
     
    Last edited by a moderator: Apr 24, 2017
  4. Mar 11, 2009 #3

    Xnn

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    Andre;

    Read the van Hoof paper carefully!.

    Their conclusion is that if anything the role of CO2 forcing should not be ignored during the period between 1000 to 1500.

    CO2 fluctuations from the Antarctica ice cores (in particular Law Dome) are not as great as they are when measured from plant stomata. However, when global CO2 forcing are calculated using the plant data, then the forcing is on the same order of magnitude as that from Solar. However, if we use the ice core data, then CO2 forcing is insignificant.

    Examine Figure 1 E carefully and answer this question:

    Should we use the red or blue line for CO2 forcing?

    Is ice core data more reliable than plant stomatal for measuring historic CO2 levels?
     
  5. Mar 11, 2009 #4
    It's not about the opinion of the writers; it's the data that they produce; and the data that others produce and the confrontation of one data set with another. Then you can make your own observations.

    Ice core data are also subject to some problems, like the gas age - ice age difference, to open firn-ice above 80 meters works as a low bypass filter, smooting out higher frequency variations.

    Red and blue line, according to the publication, are the high/low sensitivity borders.
     
  6. Mar 11, 2009 #5

    Xnn

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    Examine Figure 1 E carefully and answer this question:

    Should we use the red or blue line for CO2 forcing?
     
  7. Mar 11, 2009 #6
    Red herring You are not to toss me around :mad: in an attempt to divert from the main problem. Things don't add up.

    You can answer the question yourself.
     
  8. Mar 11, 2009 #7

    Xnn

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    A straw man argument about the role of CO2 in global warming.


    Read the Van Hoff paper.
     
  9. Mar 11, 2009 #8
    I think you're right Andre; there is no way of knowing whether co2 levels contribute to warming in an open ended system as ours. If it is warming; it's about time since in the not too distant past it seems we had a homogenous temperate climate. Everywhere from the Antartic to Siberia has tropical vegetation buried in its permafrost. Something cataclysmic happened and perhaps only now are we beginning to see recovery.
     
  10. Mar 11, 2009 #9
    Andre:
    "Not the point. The point is that there was independent variation both in CO2 and temperature. Mind that the enormous dynamic flux of CO2 between atmosphere and with the ocean dwarfs everything else. Some changes there in flows could have a big impact on that balance."

    Thank you for bringing this up. I saw the logic and I am glad that I am not the only one.
     
  11. Mar 11, 2009 #10
    Could have, might have, could maybe possibly have an impact. An enormous one by chance these variations are symptomatic indicators of the same.
     
  12. Mar 14, 2009 #11

    Gokul43201

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    And how do propose we make our own observations? Are we supposed to eyeball Fourier transforms and correlation coefficients?
     
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