Actually ... we use kelvins in science ... NOAA gives 13ºC for the 20th Century average ... we'd use 286 K in our radiative physics equations ... so in SB, the T^4 term is 6,690,585,616, not 28,561 ... [rolls eyes] ... we wouldn't use Fahrenheit either, 55ºF is the same as 405º Richter ... maybe this isn't taught anymore in chemistry class ... more lost knowledge to keep the cgs system company I guess ... I may be the only one here who knows what a torr of atmospheric pressure is ...
Anyway ... kelvin uses the same scale as Celsius ... a degree change kelvin is exactly equal to a degree change Centigrade ... thus the two are interchangeable when addressing change in the scientific literature ...
How much? .. and show your math ... I'm very curious what you're using for a constant of proportionality that's scaled in Fahrenheit ...
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ETA: My answer to the OP is "yes" ... and this AGW Theory is scientifically sound ... shine a light on a vessel of atmospheric gases and see what happens ...