Why it pays to have clever anonymice

Previously, Eli had written about Gerhard Kramm in the field of rakes. it was a mystery why Kramm thought the emissivity of the surface was .612. In the comments to the Krammfest one of the mice found the answer

Looks like kramm may have copied right off the wikipedia page for Climate Model

The problem is, he apparently does not understand what "effective emissivity" is -- ie, that it already includes the influence of the greenhouse effect due to atmosphere.

From wikipedia: * ε is the effective emissivity of earth, about 0.612

The constant πr2 can be factored out, giving

(1 − a)S = 4εσT4

This yields an average earth temperature of 288 K [3]. This is because the above equation represents the effective radiative temperature of the Earth (including the clouds and atmosphere). The use of effective emissivity already accounts for the greenhouse effect. (along with clouds and other stuff)

So, in effect, Kramm is trying to "prove" that with no greenhouse effect, the earth would have the same temperature that it actually does by using an effective emissivity that already takes into account the greenhouse effect!

Also from wikipedia:

The average emissivity of the earth is readily estimated from available data. The emissivities of terrestrial surfaces are all in the range of 0.96 to 0.99 [4] [5] (except for some small desert areas which may be as low as 0.7). Clouds, however, which cover about half of the earth’s surface, have an average emissivity of about 0.5 [6] (which must be reduced by the fourth power of the ratio of cloud absolute temperature to average earth absolute temperature) and an average cloud temperature of about 258 K [7]. Taking all this properly into account results in an effective earth emissivity of about 0.64 (earth average temperature 285 K).

Have a nice piece of cheese.