Solar spectral stumper

In the meantime, this is one of those pesky uncertainties we scientists love so much…

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254 comments on this post.
  1. Bob (Sphaerica):

    250 (Paul van Egmond),

    If I may, I don’t believe that any human fossils have ever been found that are younger than 30,000 years old. This suggests to me that humans are in fact already extinct, quite probably because they were unable to adapt to the current climate.

  2. meteor:


    Thanks for your response.
    I’m sorry for my mistake.
    I think this article (Atmospheric CO2: Principal Control Knob Governing Earth’s Temperature
    Andrew A. Lacis,* Gavin A. Schmidt, David Rind, Reto A. Ruedy)
    is fascinating and deserves perhaps a RealClimate article (it is only a suggestion).
    I’m still amazed by this sudden expansion of coverage of low clouds when the temperature has only fallen slightly.
    This would show a nonlinearity of cloud feedback.
    Do you think that there is symmetry of this phenomenon if we increase sharply the amount of CO2?

    [Response: The change from 1xCO2 to 0 is a much bigger deal than 1xCO2 to 2xCO2, and so linear assumptions about the response are not really valid – for instance, the climate sensitivity for removing all GHGs is at least 1 C/(W/m2) (and may be higher) which is significantly larger than the sensitivity for 2xCO2 in the same model 0.68 C/(W/m2). – gavin]

  3. Chris Colose:


    I have some discussion of the Schmidt et al (2010) paper at

  4. Jim Bullis, Miastrada Co.:

    232 Thomas,

    I think that if you measure IR radiation as described, you will trick yourself into believing that the atmosphere is already saturated with CO2.

    The key fact is that there is secondary radiation due to warmed air that gets warmed by absorbing IR radiation. That is a cooling mechanism that continues to get made less effective, long after the direct path is fully saturated.