Comment

When idiots attack: Climate deniers respond to one of my posts, or once again, Larry proves he doesn't understand physics 1.

8
mkelly5/24/2010 9:02:04 am PDT

The net result is that the Earth is appx. 60 degrees warmer with CO2 in the atmosphere than it would be without it.

LVQ this is incorrect. Using black body radiation formula generally gives 33 deg C as the difference. Your way off. If you meant F then your further off because it would be a 91 deg F change.

The workings: thermal equilibrium for an Earth without an atmosphere:
The sun behaves approximately like a black body of radius rs=6.599 x 105 Km, at a temperature of Ts=5,783 K. The radiative flux at the sun’s surface is given by the expression σTs4, where σ is the Stefan-Boltzmann Constant (5.6704 x 10-8 Wm2K4). Flux refers to radiation per unit area. Thus, at the Earth’s distance from the sun, res=1.496 x 108 Km, this flux is reduced by the factor (rs/res)2. The Earth’s disk has a cross section, acs=πre2, where re is the Earth’s radius (6.378 x 103 Km), and thus intercepts acsσTs4(rs/res)2 radiation from the sun. In order to balance this intercepted radiation, the Earth would warm to a temperature Te, where σTe44πre2 = acsσTs4(rs/res)2. This leads to a solution Te=272 K.

Clouds, which obviously require an atmosphere, and other features of the Earth reflect 31% of the incident radiation. Taking this into account reduces Te to 255 K.

Now 255 K is -18 C and using an average earth temperature of +15 C we have the 33 C for GHG, supposedly.
The above found at Junkscience blog. You can follow this I assume.

Any self respecting physicist would not have made the error in leaving out the temperature designation and would have been able to be more accurate in the GHG temperature increase. I now have to question your credentials. Please be more accurate next time.

By the way how is your cognitive dissonnace doing. How anyone can believe that all atmospheric gases dissipate heat and at the same time believe one gas can add more than it dissipates is beyond me. TTFN.