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Paleoclimatology and proxies

  1. Dec 6, 2009 #1
    Sorry if this has been brought up before, but when there is a temperature reconstruction for the distant past, are the different proxies weighted differently?

    Are some considered much more or much less reliable then others?
  2. jcsd
  3. Dec 6, 2009 #2
    Would you consider the fact that the Earth travels with the sun through the galactic disk once every about 32 million years causing an increase in cosmic rays leading to increase of temperature as accurate as measuring say coral or tree rings? (That of course is a theory but I'm just using it as an exaggerated example :tongue:)

    Of course some are more reliable than others... it also depends on how far into the past you would like to go and what was occuring during that period.
  4. Dec 7, 2009 #3
    Yeah, I figured there would be. Do you have something that explains it a little further?

    Like if someone were to throw out all of the tree ring stuff, for lets say the last 2k years, would the past temperature reconstruction alter dramatically (In places where the are only a loose correlation with w/e other proxies there are), or only marginally?
  5. Dec 8, 2009 #4
    Currently the most valued paleo proxy thermometer is Tex86, however, as said numeorus times before, the problem with all proxies is that it is an inherent affirming the consequent fallacy whenever there are more variables that lead to the same proxie values.

    And if you really zoom in to that problem, it is looking ugly.
  6. Dec 8, 2009 #5


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    Tree rings have their limitation since they don't grow everywhere
    and moisture levels affect their growth as does CO2 levels.
    If all the tree ring data were to be thrown out it wouldn't matter very much.
    There are other proxies available:

    Ice cores
    Lake/Ocean Sediment
    Cave deposites

    In addition, a lot of research is focused on time periods that do not
    rely upon tree rings. For example, during the Pliocene
    (between 2.5 to 5 Million years ago) we know the climate was
    very warm but with CO2 levels similar to today. However that
    temperature determination is not based on tree rings at all.
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