Poirot,

'I believe I could have written something more detailed on AGW ...'

I believe you could too. So please go ahead it would be a welcome change from your usual one or two line posts... and would reveal the real depth of your intellect.

cheers

Ok cohenite, so 235 W/m^2 is the 'effective temperature' or the forcing that is not due to greenhouse gasses, as you have described it in an earlier post. And I can see on the formula that the start point is 233.6. Although I don't understand the statement "Below 235W/m2 CO2 has no effect". Huh? Now you're just spouting gibberish in the vain hope that you will seem smart to the drooling masses. Surely that just translates to "below 0ppm CO2 has no effect"? Der.

Anyway, I don't think you can prove that CO2 has a log relationship using a graph that uses a Log2 function to plot, that's just circular.

So where does the formula Forcing=2.94Log2(CO2)+233.6 (R^2=.997) that is used to generate the graph come from? Who determined the wonderfully perfect Log2 relationship? References please. I am having fun exploring this, so please don't spout gibberish at me again and provide some actual paper references or links to websites that have references to papers.

I need to find out, is this log2 relationship computed from the radiation absorbing properties of CO2 or does it take other considerations into account, such as water vapour? If the graph takes the "effective temperature"
into account, does it take other factors into account also?

As an aside, if you play with the graph and plot just the section of the graph post pre-industrial CO2, then you get an increase in forcing that is almost linear, it's not quite linear, but it's pretty damn close. And the increase in RF does not approach zero, but does get ever so slightly less with each ppm increase, using that formula.

I think you should not get hung up on the effect of very low concentrations of CO2 and focus more on the current forcings of CO2 and what that actually means.

Listen Bugs, what did your last slave die of? If you think I'm going to run around the blogsphere doing your errands guess again.

Why don't you have a think about the effective temperature which is what Earth would have without GHGs, ie 255K and what the Earth's temperature really is presumably due to the presence of GHGs, ie 288K, the difference being 33K, being the Greenhouse temperature so that GAT is ~ 15C.

Logic would tell you that CO2 has no input into the effective temperature because it is the temperature of the Earth WITHOUT GHGs; CO2's contribution to the GAT is in the 33K extra supplied by the GHGs.

Now if you read the rest of that link you will see that CO2's contribution to the 33K is at the beginning of that 33K; CO2 does most of its work in its lower levels; as the concentration increases CO2's capacity decreases either logarithmically or exponentially; never completely ceasing but becoming increasingly proportionally insignificant.

As for your demands for sources of the graph drawer at WUWT; I don't know. But they're alternatives; long answer:

http://jennifermarohasy.com/2009/03/radical-new-hypothesis-on-the-effect-of-greenhouse-gases/?cp=11#comment-87599

Its by Michael Hammer an expert in spectroscopy.

Short answer; The general Beer-Lambert law which is usually written as:

A = a x b x c

Where A is the measured absorbance, a is a wavelength-dependent absorptivity coefficient, b is the path length, and c is the analyte concentration.

So as c decreases b increases.

The result of this is that CO2 emissivity, the measure of how much radiation the concentration of CO2 absorbs, DECLINES as the concentration increases.

Gosh cohenite, you are funnier than a barrel full of monkeys.

What about some basics. You do know that the size of 1 Kelvin is the same as 1 degree C? So 33K difference is actually 33C, not 15C.

If you have a curve that asymptote so to 1, that means it reaches the number 1 on your scale, not 292.

Now as to this new graph you have introduced, you know the one that doesn't asymptote, but which in cohenite universe asymptotes to 1. You introduced that graph as something important to the discussion. If you cannot answer questions about it, then we should probably assume it is just more rubbish you have parroted from one of hose denier blogs.

I am interested in why, if you make the CO2 concentration really really small, the net downward forcing goes negative. Now how does that work?

Please do tell.

Cohenite, all you had to say was that it was the bbaseline radiative forcing that has been calculated without the effect of greenhouse gasses, which is why 0ppm CO2 starts there. Then by definition it is without CO2. I'm prepared to accept that at face value. But to go on and on spouting nonsensical phrases about that and calling it the "effective temperature" is bizarre (*temp is measured in degrees). It just confuses people. BBB I guess.

Your restatement of Beers law in that way tells me all anyone needs to know about your understanding of formulae.

As the analyte concentration decreases, the path length increases? Yes, if A is constant, but A is a measurement and won't be constant, it will increase as the analyte concentration increases.

That is, if you have stated it correctly. Have you stated it correctly Cohenite?

Your last sentence is definitely not stated correctly. Absorbance does not decline as an analyte concentration increases.

It's ok, I know science communication is not your strong suit. It's much easier communicating with people who think they know what you are talking about because you both assume the same starting position.

As far as I can tell going through all these blogsites, is that they all seem to agree on their conclusions, but none of them seem to be able to calculate numbers that agree with each other. It's weird, unless of course you assume the conclusion and work backwards.

BTW cohenite, thanks for the admission that you don't know who drew the graphs or what they based their formula on (I still can't find the formula anywhere else).

Yeah, that PROVES it!