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Cause of Halocene warming?

  1. Sep 28, 2009 #1
    What might be underlying possible causes(s) of Halocene warming over last 15000 years? Any mild Milankovitch forcing by just 20k precession effect? http://en.wikipedia.org/wiki/Milankovitch_Forcing" [Broken]
     
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Sep 28, 2009 #2

    Xnn

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    Besides differances in earths orbit that caused the perihelion to occur closer in time to the NH summer, there were substantial increases in greenhouse gases (CO2 and Methane).

    Hard to say offhand how much each of these contributed (percentage wise) to the warming, but they are all factors.
     
  4. Oct 7, 2009 #3
    Re: Cause of Holocene warming?

    The top 2.5-3.5 meters of ocean heat capacity is ~ equal to that of atmosphere; see Ocean Heat Storage thread. Since the LGM 20,000 years ago, and over Holocene of ~15,000 years, one has had gradual overall warming of atmosphere (ice core gases?) and supposedly of average ocean temperature. Might upper layer of ocean, for over 15,000 years, perhaps statistically have had less vertical turnover, leading to gradual increased surface warming, and secondary atmosphere warming? Might any such background primary warming of ocean upper layer have had much more of an effect on atmospheric warming and observed consequences, than just increase in CO2 (just 280 -> ~385 ppm for last ~200 yrs)? Thus is the paradox of just ~35% increase in CO2, compared to observed apparent greater consequences, related more initially to oceanic heat dynamics?
     
  5. Oct 7, 2009 #4

    Xnn

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    Highly accurate temperature measurements of the ocean have been made for about 50 years.
    These are measurement that extend to great depths (using buoys and other devices).
    From these measurements, it has become clear that the oceans are warming.
    So, heat has been flowing from the atmosphere into the oceans.

    The rate of vertical turnover in oceans is another matter. As far as I know, there is not a clear conclusion as to wether the turnover is slowing down or not. If it does slow down, then the atmosphere would warm faster than it has been.
     
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