Return of the dead: global cooling

I assume this is all mostly a matter of stupidity and mischief making rather than any concerted attack, but the 1971 R+S science paper makes an unexpected comeback. Tim Lambert has the story; Lubos falls for the lies (I’m being a bit inaccurate there: Lubos doesn’t fall for it, he jumps in with enthusiasm and ignorance).

Whats the point of all this? The usual mixture I suppose: you have to fill newspapers with something; that its wrong doesn’t really bother anyone; that its misinformation serves the usual purposes. And it does in part so serve: I’ve just had to remove As a research associate at Columbia University in 1971, Hansen wrote a climate modeling program which predicted that fossil fuel burning would discharge enough fine dust in the atmosphere that much of the sun’s rays would be screened out. His software predicted that this “global cooling” would lower Earth’s average temperature by six degrees within fifty years from Hansens entry on wikipedia; the tories wander around and no-one checks.

More at for those coming to this late.

8 thoughts on “Return of the dead: global cooling”

  1. Once more, just for completeness. The model had nothing to do with the prediction, which was merely an expression of the assumed (by _&S) climate sensitivity to CO2. As _&S pointed out, in _&S, the value they assumed for the calculation was lower than one that everyone else had. When _&S used the better and higher climate sensitivity, the cooling disappeared as the CO2 forcing overcame the aerosol forcing.

    Having said that, I recall an earlier, much earlier, interchange when the _&S estimate for aerosol forcing was discussed, and there was general agreement that _&S were very close to being correct on that.

    [I don’t think R&S assumed a value for CS. That comes out of their model. They made various assumptions (constant abs humidity?) that ended up with a low CS. Saying that everyone else had a better value is wrong/misleading. There was no known value. They point out (note 3?) that Manabe had a value 3x as big; at that point, Manabes value couldn’t be known to be “correct”. I don’t understand your “when the better value was used the cooling disappeared” (are you saying they published this?). The cooling is still stronger; what changed is that 8x aerosol became obviously implausible -W]


  2. Lubos is entering his manic phase. The value of talking to him rather than signing the commitment papers is going negative. Michael Berube has a good description of what is going on, Motl is rapidly becoming like the dotty uncle who comes down from the attic every Christmas, yells at everyone for twenty minutes and goes back up the stairs. See his treatment of comments.


  3. Off-topic: What was the main factor in the onset of cooling (and thereafter – CO2 conc. decrease?) during the interglacials in the past? Decrese of sun activity? Gulf stream shut-down? Thriving phytoplankton in cooler oceans (as a positive feedback in sucking CO2 trom air)? Combination of above mentioned? Any literature?

    Thanks! 😉

    [Because of the 100 kyr periodicity (and 40 and 20 kyr too) the ultimate forcing is known reasonably well to be orbital variation, and probably of the Milankovitch style. Which is to say, variations in the patterns of insolation at the surface – variations by latitude and season. It has to be this because of the coincidence of periodicity and regularity -W]


  4. Missing the main points aren’t we? Points that should make you pause for thought at least.

    a. Journalists go way over the top ignoring all caveats and scientists seem happy to go along for the ride, presumably just to have their name in the papers. And it’s still happening isn’t it? Real misinformation.

    [Journalists certainly go way over the top, or at least there will always be some that do. Scientists are generally unhappy with, but resigned to, how their words end up mangled by the press. The motto is obvious: don’t get your sci info from the press (or, most likely, any other info you can’t check).

    b. Climate models reflect the assumptions and biases of the modelers. Fossil fuels – not sure what they do but we’ll pin something on them that’s for sure.

    [Thats just your own biases showing -W]

    Basically they changed their mind because temperatures started going up not because their models, calculations or assumptions got any more accurate.

    [I wonder why I bother sometimes; but if you won’t read the truth when its put in front of you there is little hope -W]


  5. Out of curiousity, can someone explain in layman’s terms, what Hansen did provide to the R+S paper? Albedo calculations, apparently, but it’s all gibberish to me.


  6. “…how their words end up mangled by the press”
    You mean like this example:
    “Modeling of long-term fossil fuel consumption shows 14.5-degree hike in Earth’s temperature” from
    There are countless examples of this type of press release sensationalism. Yes probably the caveats are all in the original report but the PR folk always check first with the scientists concerned. They are not so innocent as you would have us believe.
    And I’m not fond of fossil fuels either because of their more direct pollution so I’m not biased against reductions at all – I just like the plain truth rather than guesswork ans spin masquerading as truth.

    [That report seems fair enough, once you’ve realised they mean oF and several centuries, but then they are americans. I’m not sure what you’re trying to prove: there are any number of bad press statements out there, whats the point of quoting them? -W]


  7. cce: Here is what Hansen says, “What was that program? It was a ‘Mie scattering’ code I had written to calculate light scattering by spherical particles. Indeed, it was useful for Venus studies, as it helped determine the size and refractive index of the particles in the clouds that veil the surface of Venus. I was glad to let Rasool and Schneider use that program to calculate scattering by aerosols. But Mie scattering functions, although more complex, are like sine and cosine mathematical functions, simply a useful tool for many problems. Allowing this scattering function to be used by other people does not in any way make me responsible for a climate theory.”

    Being a physicist, I can attest that Hansen’s description of Mie theory code is absolutely correct. Mie Theory was worked out in the early 1900s to describe the scattering and absorption of light by a spherical particle. It is pretty much the simplest light scattering problem one can think of and the solution basically involves calculating an infinite series that contains lots of “fun” mathematical functions like spherical bessel functions and Legendre Polynomials. The bigger the particle compared to the wavelength of light, the more terms in the series have to be kept before they become negligible. In the days before computers, working out Mie theory was pretty complicated…and even in the early days of computers, it took a little bit of talent to come up with (or learn from others) good ways to compute these mathematical functions. Nowadays, a programming language like MATLAB has Bessel functions and Legendre Polynomials built-in making the task much easier.

    I too have written Mie theory code and I don’t do any work related to climate science. I imagine pretty much any person who has worked on light scattering and absorption by small particles for whatever reason has either written a Mie theory code or used someone else’s. (These days, there are publicly available codes on the web.)

    Suggesting that Hansen is somehow responsible for the results of an early climate modeling study because they used his Mie theory code is frankly bizarre! They might as well label Legendre or Bessel or Mie as proponents of global cooling by that sort of logic. (These people are, of course, long dead.)


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