tisdag 6 september 2011

War Against Spencer-Braswell Low Climate Sensitivity

Climate science is fascinating: It concerns the complex system of global climate but it is studied using very simplistic mathematics. The Spencer-Braswell paper concerns fitting a very simplistic mathematical model of global climate of the form
• C dT/dt = F(t) - lambda T(t)
to measured data in order to determine the (positive) feedback coefficient lambda. Here T(t) can be sea surface temperature SST as function of time t, C is the heat capacity of the Earth-atmosphere system, F(t) is radiative forcing and S = 1/lambda measures climate sensitivity as change dT of T vs change dF of F in stationary state:
• dT = S dF
If lambda is small, then the sensitivity S is large and a small change of forcing dF can have a large effect dT on temperature T.

S is the holy grail of climate science: If S = 1 (large) then there may be reason for climate alarmism. If S = 0.1 (small) then there is no reason for alarm. The climate system is then so stable that an effect of doubled CO2 can never be measured or detected.

If S = 0.1 then a change of radiative forcing of 10 W/m2 (quite big out of a total of about 250 W/m2 with natural variability about 5 W/m2) could cause 1 C of warming. Nothing to worry about.

The radiative forcing from doubled CO2 can be estimated to be in the range 0f 1 - 4 W/m2, which with S = 0.1 gives a climate sensitivity of 0.1 - 0. 4 C, which is not at all alarming.

Now Spencer and Braswell determine the coefficients C and lambda in the above model from a best fit to measured time series of T(t) (from SST) and F(t) (from ERBE), and make the following observations:
• S < 0.3
• IPCC models give S > 1
• if F(t) is not properly measured then S cannot be reliably determined.
That this has caused an uproar is understandable: If S < 0.3, then climate alarmism collapses.

Now, there is a wealth of measurements of time series T(t) and F(t) which all indicate that S is smaller than 0.2, presented in work by Spencer, Lindzen and many others.

One can also use variations over time (diurnal, seasonal) and space (regional) of T and F to estimate S, see a summary of my posts on climate sensitivity on Basic Science: Climate Sensitivity < 0.3 C.

The Spencer-Braswell paper in all its innocence is thus a blockbuster to climate alarmism, and it is clear that it has to be eliminated, one way or the other no matter what the costs are.

Spencer is expecting the worst: More Thoughts an the War Being Waged Against Us.

The story is unfolding in real time with an IPCC in free fall...see What is IPPC Afraid Of? ...

PS A simple model correctly illustrating some fundamental real aspect, is valuable because this helps understanding . The above model can serve this purpose in the stable case with lambda > 1, but the model is too simple to detect a small lambda and large sensitivity.

10 kommentarer:

1. Claes, did you see the link to this nonsense full paper on WUWT as follows http://wattsupwiththat.files.wordpress.com/2011/09/dessler_2011_grl.pdf
It seems that Dessler's understanding of heat transfer (convection & phase change in particular) is zero. One should also credit Trenberth, who appears to be one of the papers reviewers (see acknowledgements), with lack of understanding. Trenberth is committing scientific fraud by not correcting or withdraw his earlier heat balance papers which show an atmospheric radiation window of 40 W/m2 when he has admitted he knows that satellite measurements show the radiation window to be 66 W/m2.
I think the CAGW "team" have kicked an own goal over the S&B paper. One can smell the panic as there lack of knowledge and fiddling of data is exposed.
keep strong
cementafriend

2. Exactly how do Dessler's acknowledgements indicate Trenberth was one of the reviewers?

3. Anon: You should note that Dessler used the same model that Lindzen & Choi did and that Spencer & Braswell did.

4. Claes, my Venus/Earth comparison, which is definitive, already indicates a lower "CO2 climate sensitivity" than any you mention, again essentially zero over the range from 0.04% CO2 (Earth) to 96.5% (Venus). Taking account of the uncertainty in the Venus data (+/- 1.4K in the temperature at any given pressure, due to reading the data off the available graphs), the indicated sensitivity is about -0.03 +/- 0.1 K per doubling of CO2. (Yes, it's a negative very small number, and yes it is really essentially zero).

5. That is fine! The important thing is that climate sensitivity is small; it does not matter if it is 0.3, 0.03 or 0.003 C, plus or minus.

6. Huffman's calculation is in no way "definitive"--he won't even submit it to peer review. Instead he sent a letter to Physics Today and then whined when they wouldn't publish it, as if decades-old science would be simply tossed aside on his say so.

7. PS: For even more of Huffman's whacked ideas, see his Blogger profile with its links to his Amazon and Lulu pages. His books--all self-published--purport to overturn the theory of plate tectonics, and he claims to have found a "grand design" to the solar system. He is what's known as a "crank," and like all cranks, has a grandiose notion that he alone is right.

8. David Appell,

You are a liar (I have not "whined", and have not refused to submit to peer review), not a scientist and not even a responsible science journalist as you have claimed to me, merely one dedicated to impugning criticism of the climate consensus. I have not found peer-review journals any more open than you are, and your own words here well illustrate how lacking in openness you are. If you want to do something worthwhile, try approaching peer-review journals that are open to the public ("Nature", "Science", "Scientific American", etc.) with my Venus/Earth comparison (just give them a link to it:

http://theendofthemystery.blogspot.com/2010/11/venus-no-greenhouse-effect.html

and if one of them expresses an interest in publishing that comparison, as I have done it, you can get in touch with me and I will send them a submission. Or, prove that I am wrong in the science I have been communicating, which will take you the rest of your life and keep you out of competent people's hair. But you are an empty wind, and theirs is a corrupt system, suborned by an incompetent climate consensus. Put up or shut up, so far you are obviously not on the side of open inquiry in science (or even respect for others), and that puts you beyond the pale to this competent scientist and open-hearted human being.

9. Interested readers can visit my site, where David Appell has just in fact tried to "put up" a devastating criticism of my Venus/Earth analysis, in a new comment that does nothing but show his utter ignorance, not only of what I have written, but what the climate consensus puts out in their "explanations" of the greenhouse effect. You can also read my latest post, "Blackbody -- The Key Error in Climate Science".

10. HDH: I would be laughed out of my profession if I presented your simplistic "arguments" to any scientific journal or magazine like SciAm. As I and other commenters have pointed out to you many times, your argument ignores direct observations on outgoing radiation, ignores observations like stratospheric cooling, and applies the ideal gas law where it does not fit. The greenhouse effect is firmly established science for over a century and has been verified by repeated satellite measurements, such as "Increases in greenhouse forcing inferred from the outgoing longwave radiation spectra of the Earth in 1970 and 1997," J.E. Harries et al, Nature 410, 355-357 (15 March 2001).
http://www.nature.com/nature/journal/v410/n6826/abs/410355a0.html

You can submit your own paper. They get stuff like that all the time. Good luck!