60% CO2 Would Be Snowball Earth

[UPDATE : Correction below. It doesn’t change the conclusion.]

I tried an experiment on RRTM – the radiative transfer model used by NCAR’s climate and weather models – which shows how ridiculous the Hansen/Sagan runaway greenhouse effect is. The control run used current conditions in the tropics – 299K, 2% H20, 393 ppm CO2. This is what it produced :

             mb          W/m2          W/m2           W/m2          degree/day
   0     1013.         459.2934      397.0788        62.2146           -2.92635

The downward LW flux at the surface is 397 w/m2. Next I tried the same experiment with a 95% CO2/0% water atmosphere, which is similar to Venus :

[UPDATE : The numbers below are incorrect. It turns out that the model is not stable at 95% CO2]

 LEVEL PRESSURE UPWARD FLUX DOWNWARD FLUX NET FLUX HEATING RATE mb W/m2 W/m2 W/m2 degree/day    0     1013.         459.2930       36.8353       422.4577           -0.50246

The downward LW flux drops to less than one-tenth of the normal atmosphere.

[UPDATE : Here are more accurate numbers at 60% CO2]

Next I tried the same experiment with a 60% CO2/0% water atmosphere. That is 1,500 times more CO2 than the atmosphere actually has.

             mb          W/m2          W/m2           W/m2          degree/day
   0     1013.         459.2943      308.5074       150.7869           -0.99265

The downwards LW flux drops by 23%. Snowball Earth.

Why? because H2O is by far the most important greenhouse gas. The absorption spectra of H2O at 1000mb is much wider than CO2. Without the high pressure on Venus, it would be a cold planet more like Mars – which also has 95% CO2.

Conclusion : the Sagan/Hansen runaway greenhouse effect is complete nonsense, and if Hansen was a competent climate modeler he would already know this.

About stevengoddard

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20 Responses to 60% CO2 Would Be Snowball Earth

  1. Baa Humbug says:

    A competent lying sob

  2. chris y says:

    Wait a minute. Andy Lacis and friends at NASA GISS just published a paper last year claiming that CO2 dominates the climate. To show this, they ran their models with an instantaneous drop of CO2 to zero ppm, and found that an iceball Earth resulted as all water vapor dropped out of the atmosphere.

    0 ppm CO2 = iceball Earth
    950,000 ppm CO2 = iceball Earth

    So are we back to the Goldilocks story again?

  3. suyts says:

    lol, very nice………. waiting……..

  4. Mike Davis says:

    I read some of the Lacis paper and thought they were trying to prove without a doubt that GIGO rules Climatology.

  5. Andy Weiss says:

    As a non-scientist, it’s interesting to see what the science actually says. There a lot of science “wanna-be’s” out there who are running their mouths and don’t WTF they are talking about.

  6. slimething says:

    Personally, I’d like it explained mathematically how a few ppm change in CO2 can be attributed to a corresponding change in OHC.

    My back-of-the-envelope calculations indicate it is ludicrous once heat capacity of CO2 is taken into account. Saying CO2 “slows cooling” or that waves turning over mix the warm skin layer downward seems like arm waiving if not downright grasping at straws.

    • Ben says:

      Slimething, those are actually reasonable mechanisms. However, while such explainations can justify why we do not see a strong CO2-control signature in the climate, they do not give evidence for CO2 dominance. Indeed, they show that CO2 is one of many factors, and no greater (indeed, it is significantly weaker) than the others

  7. suyts says:


    How long has the original article been up? I don’t have a problem with people not catching the instability of the model, there would be many reasons for that, which have nothing to do with scientific understanding.

    Steve states an hypothesis as to why temps are so hot on Venus. Critics of the hypothesis vociferously argued against it. Many making valid points given the current understanding of climate. But Steve mentions the word “model” and nary a peep. Its especially ironic in that he used RRTM. (Radiative transfer for those not following along at home.) Great choice Steve!

    Maybe, today they are all too busy tidying things up for the weekend. Maybe they will give us their insights later on this evening. Or, maybe they believe models are gospel and think it is blasphemy to argue against the results of a model. What a horrible quandary for the warmistas.

    • I realized the problem about ten minutes after putting it up, by running some more experiments. The model becomes unstable above 60% CO2, which is also the region where it flattens very quickly.

      • suyts says:

        Yeh, which is more to the humor of the situation. I really believe our learned friends are so entrenched in their dogma that they’re afraid to argue against a model. We’ll have to see………..

  8. Amino Acids in Meteorites says:

    Plenty of dry ice for Ozzy Osborne concerts–hehe.

  9. Peter Ellis says:

    Why are you assuming a constant atmospheric pressure?

    • Why would you want to add another degree of freedom to a correctly constrained calculation?

    • Mike Davis says:

      Consider it business as usual! All climate models are based on assumptions, estimates and extrapolations with parameters that can be tuned to fit the agenda!

    • Amino Acids in Meteorites says:

      Peter Ellis says:
      April 23, 2011 at 7:37 am

      Why are you assuming a constant atmospheric pressure?


      One thing I assume is that you don’t know what you are talking about Peter.

  10. TimoH says:

    Personally I think these models are just absolutely wrong, actually water evaporation and wapor and clouds are strong negative feedback, they trap incoming light before it even reach surface to warm it, and atmosphere can´t warm itshelf, that energy is from sun and surface, if surface gets less energy, also atmosphere will be cooler sooner or later.

    I´m sorry, my english are not so smooth as it could be and i´m also suffering hangover.

    Form examble, when trade wins are weakening and El Nino occurs, surface water gets warmer, it increases evaporation which transport this heat to the atmosphere, this moisture trap in coming sunlight, cloudines will also increase, it reflect and trap sunlight.

    So atmosphere gets warmer first, but because evaporation increases and sunlight comes in less, the result is that seawater gets colder and atmosphere also with delay,
    thats why warmest point is then when la nina has already started,
    then evaporation at equator decreases, so sunlight come more in,
    but warm seawater drifts to the poles and evaporate, so there is also a lot of heat trapping moisture and clouds at poles until they rain down.

    I think that all climatechanges in the past was happened because long scale changes example in jet streams, trade wins and so on, which are reason and or result of sea currents long scale oscillations, it newer had nothing to do with co2.

    Always when its getting warmer, evaporation increases, vapor increases, cloudines inreases,
    result is cooler sea surface and cooler atmosphere and it all starts again, temperature oscillates around this beautiful thermostate,
    which can be changed significantly only by changes in sun UV which drives jet streams, or atmosphere pressure or continental drift, or all of them,
    and in long time scale water always try to resist this change, never amplify it.

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