Can you find any citation for "his popular formula?"
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John,
re: the ΔF = α ln(C/Co) equation.
I'd hoped you might update your last post, but....
I'm sure you'll realize that 200/280 is not "upside down" as you suggested, but is just an example of a final CO2 concentration
lower than the "standard" initial concentration of 280ppm [Co] used for the reference point (based on the pre-industrial level).
So, if somehow CO2 levels were to be brought down to 200, the graph shows that the forcing would be negative (relative to the forcing at 280).
For this equation, F is negative for the natural log of fractions (less than one); 200/280 = 0.7143....
I only included the (far-fetched) example of 200/280, to show how the equation would graph if the x axis measured C/Co, instead of the way you set it up.
This whole claim about the logarithmic effect of CO2, thus meaning that CO2 didn't matter, came about out of Richards comments:
Aside from anything else, there is no indication at all that shows that CO2 actually is a greehouse gas in the sense of the term being that it traps heat from the sun that otherwise would not be trapped.
... on the 4th post of this thread.
I have agreed that there's plenty of room for debate over the value of alpha; the how, where, and when of CO2's effects.
However, four pages later, I hope it's persuasive that whatever adjustments might need to be made to alpha, the adjustments have nothing to do with this recently suggested logarithmic effect of CO2. The only references to this newly incorporated effect comes from the blogosphere, a few private websites, and some uncitable graphs; and are based on obsolete information or unsupportable interpretations of a gas's physical parameters.
Adjustments to alpha would depend on the positive and negative feedbacks related to humidity, clouds, and various other atmospheric dynamics.
Why is it that you think the IPCC estimate for alpha is too high?
Cirrus clouds perhaps?
~Later,
...
