Can anyone help on this ?

I have red in a few places that the theoretical global temperature increase for a 'doubling' of CO2, with no additional feedbacks considered, would be about 1 degree Fahrenheit. With additional feednacks, the commonly quoted number is 3 degrees centigrade.

I can't find any references to the theroretical forcing from CO2 alone (1 degree F). I was sure it had been quoted in an IPCC report but can't find it.

Can anyone point me to a reference for this ? Thanks.

I was looking for a link to the "Frequency - Wavelength Converter" included on that old "climate surfings" thread:
http://www.scienceagogo.com/forum/ubbthreads.php?ubb=showflat&Number=26454#Post26454

...and I ran across this. Thought it might be helpful:

http://www.realclimate.org/index.php/archives/2008/04/back-to-the-future/#comment-89262
The energy of a 15micron photon is 1.325×10^-20 joules; its momentum is 4.4×10^-29.
The kinetic energy of a CO2 molecule at 300K is 6.214×10^-21 joules (3742 joules for a mol); its momentum is 3.0×10^-23; its velocity (or the average velocity for a mol) is 412.5 m/sec.
One photon’s energy going into one molecule’s translation will raise its temperature from 300K to 630K; the mol’s avg. temp would increase to 300.038K.

...or maybe someone over there could help out more.

~

The IPCC statement of a 1.2 K rise is http://www.grida.no/publications/other/ipcc%5Ftar/?src=/climate/ipcc_tar/wg1/044.htm

A quick back-of-envelope calculation is that dE/DT = 1/[4sigmaT^3] whee dE is the radiative forcing for a doubling, roughly 5.35 ln 2 (Myhre et al 1998). Let's say 4 W/m2 per doubling and 4sigmaT^3 is the slope of Stefan-Boltzmann.

or, 4/4sigmaT^3 where T is the radiating temperature of the planet (not the surface) which is 255 K. That gives roughly a 1 K rise (not F).

Thanks ..... what I was trying to work out was how much T increase going from an ice age to an interglacial period is due purely to the CO2. The CO2 increased fom 180ppm to 280ppm so I guess this would work out at about 0.75 degrees C. Out of about 5 degrees total rise (global average).

Thanks again.