hunter, don’t waste your time. You’re talking someone with a “Che” teeshirt in his closet most likely. Reads “Rules for Radicals” as if it were a lost gospel. So when the MSM pushes the political slander button on a tragic event they know their audience.
http://www.anncoulter.com/columns/2011-07-27.html
“Science was my religion”, “left wing”. What tribe does that remind you of?
aa,
You know what it proves: That AGW is a pile conflicting oxymoronic crap.
You just hope it will all go away and leave you to the comfort of your faith.
Too bad.
tt –
You consider that a serious threat? Really?
Let’s not get any more obtuse than we have to, eh?
Or don’t you realize that Hansen had nothing to do with Climategate?
Keep’em coming – I’m having fun with this.
I read it long ago – and heartily concur that it’s a great source and a good read.
Peter – you are your own worst enemy
I would also prefer simple and straightforward evidence, but I have told, why I believe that having it at a level that can be presented in net discussion is not possible.
We can tell our arguments to a point, but there’s a limit on that. Real scientific publications are the venue for the most complete discussion, when things get too complicated for net discussion.
I do sincerely hope that more working climate scientists would join the critical discussion, where also stupid comments are allowed and where the approach differs from that of RC, but I don’t expect that everything could be discussed properly on this kind of sites even with their participation.
For some reason no site that I know has been able to attract critical technical discussion of the type that I would consider most valuable for people, who have solid background knowledge, but who are not working climate scientists.
Tom: Vaughn has posted a detailed scientific argument for discussion. Saying it should not be posted and that he does not understand basic physics just makes you look stupid, as neither is a counter argument. We are here to work, not to trade insults.
Back radiation is a phrase, one that I don’t use myself, and it is not a word that is used in technical radiative transfer studies. The argument is made technically from the spectral infrared absorption and emission of CO2 and other gases.
Thanks David. Vaughan has written an essay that is useful in focusing the greenhouse dragon discussion.
“While I seriously doubt whether climate skeptics will thank me for pointing it out, I don’t believe their arguments impress the swing voters in the climate debate as convincingly as they might”.
The swing voter pays little or no attention to either side. We just like to think we’re very influential …
http://thepointman.wordpress.com/2011/08/04/i%e2%80%99m-not-a-scientist-but-%e2%80%a6/
Pointman
Al, I am pretty sure I know what you mean by “CO2 wavelengths”… CO2 absorbs some wavelengths very strongly, and others not very much at all; so I presume you mean those wavelengths which CO2 absorbs. (Correct me if I misunderstand you.)
However, note that there is a continuous variation. One of the major reasons CO2 makes a significant difference as you keep increasing it anywhere along the range from 10 ppm to 100,000 ppm is that the atmosphere as a whole becomes opaque to more and more wavelengths. For example, let us say the atmosphere is “mostly transparent” at those wavelengths where 50% or more of that wavelength gets through, and “mostly opaque” at wavelengths where 50% or more is absorbed. As concentrations of CO2 increase, more and more wavelengths move from being mostly transparent to mostly opaque; this is called absorption in the “wings” or “shoulder” of the main absorption band.
Hence the concept of optical depth is indeed crucial, as you say. However, your concluding inference is back to front. It is the continuous relationship between optical depth and wavelengths which means that you do get a significant and continuous change in the loss of heat from the surface into space (very close to a logarithmic relationship) as CO2 concentrations range over values anything from 10 to 100000 ppm. What we could plausibly see on Earth is all well inside that range.
BTW. The atmosphere heats the surface in the same sense exactly that a blanket heats a sleeper. (Though the physical mechanism is a bit different.) As Vaughan points out, the net heat flows are from the surface to the atmosphere; the surface heats the atmosphere, and the atmosphere cools the Earth. So too, look at the heat flows and you see that a blanket doesn’t heat you; YOU heat the blanket.
You are warmer with the blanket than without, and so in normal speech we do say that a blanket is warmer than a sheet, or than nothing at all. Objections to this usage may be pedantically correct; but I’m still going to speak of “sunrise” for the Earth turning towards the Sun, of being warmed by a wool blanket, and of being warmed by the atmosphere.
Dr. Curry,
Most skeptics I am aware of do not agree with the Greenhouse Dragon.
Using the Dragon as a proxy for ‘what skeptics believe’ is a bit of a straw man.
Spencer, Lindzen, Pielke, Sr. and Salby all have critiques of AGW catastrophism that has nothing to do with the Dragon.
While it is as much fun to attack a fringe like the Dragon, as it is to jump on Gore or Romm or Hansen for their ‘fever’ talk, or spittle flecked spews or tipping points, I do not believe that many in the AGW community actually support such extremist non-science from that side either.
Perhaps it would be more constructive to not kick a dead dragon?
Judith,
You should thank David here.
I wrote a comment in the previous “dragon thread”.
http://judithcurry.com/2011/08/10/greenhouse-dragon-technical-discussion-thread/#comment-97627
That presents in very rough terms a different way of looking at the same physics – and without direct reference to back radiation in any way. As I said, the physics is still the same, only the way of looking at it differs.
Tens of centimeters not meters. Ten of meters was debunked on another thread a few weeks ago.
It is hard to tell whether this article is making a point worth contemplating or not. It seems to me the gist is that the net longwave flux is upward. That is, the upweard is bigger than the downward. This nasa presentation:
http://science.larc.nasa.gov/ceres/STM/2003-05/pdf/smith.pdf
does a nice job of showing the values. But whether that makes any difference at all in the arguments comes down to whether the climate models include BOTH the downward and upward flux, which is net upwards, or if they only take the downward into account in which case they would be totally wrong.
Since I don;t know whether the models include both, with the net being upward, then I don;t know whether the point of this article favors skeptical arguments or the AGW modelers.
What you are describing is the maximum entropy principle. Assume the minimal information known about the process, such as a mean, and then use the probability distributions that arise from maximum entropy. This approach is studiously avoided by lots of people. For example, it is not mentioned in Curry’s paper even though that is the basis of properly applying uncertainty propagation, starting from the large spread in CO2 residence times. Most of these writers are neophytes when it comes to doing stochastic phenomenon properly.
Vaughan Pratt
What evidence do you have for your statement:
“Preindustrially this flux was in balance and CO2 was not under any great pressure to change rapidly in a single century”
The 4% anthropogenic contribution must be compared with varying natural CO2 fluxes caused by variations in temperature and moisture etc. See Murry Salby’s presentation
JoNova provides some figs. Blockbuster: Planetary temperature controls CO2 levels — not humans
“I don’t believe their arguments impress the swing voters in the climate debate as convincingly as they might.”
More speculation in climate science that is really just politics. Just what we need. Yawn.
Andrew
Your calculations are impeccable. However, the 3.7 wm-2 we are talking about do not disappear from the earth’s surface. It is radiated out into space from somewhere else in the atmosphere. Your calcualations apply to wherever this is; NOT to the earth’s surface.
I am not going to enter into a disucssion on this. You can go straight to Wikipedia and argue with these sources:
Rahmstorf, Stefan (2008). “Anthropogenic Climate Change: Revisiting the Facts”. In Zedillo, E. (PDF). Global Warming: Looking Beyond Kyoto. Brookings Institution Press. pp. 34–53.
“”Without any feedbacks, a doubling of CO2 (which amounts to a forcing of 3.7 W/m2) would result in 1°C global warming, which is easy to calculate and is undisputed. The remaining uncertainty is due entirely to feedbacks in the system, namely, the water vapor feedback, the ice-albedo feedback, the cloud feedback, and the lapse rate feedback”;[6] addition of these feedbacks leads to a value of approximately 3°C ± 1.5°C.”
