gw quiz #2 the next question in our how-to-spot-a-global-warming-whacko series: how exactly does the greenhouse effect keep a planet toasty warm instead of frozen solid? this is a bit of a trick question. first the stock answer which is acceptable. the atmosphere is more/less transparent to the light put out by the sun. the earth absorbs it. and re-radiates it at different much lower frequencies. the atmosphere is most definitely not transparent to this radiation. much of this radiation is absorbed as heat and/or redirected back to earth. some gets through. but not much. like a blanket. since the heat can't get out, it accumulates in/on the earth. and the temperature rises. and the black body spectrum of the earth shifts towards higher frequencies. until eventually enough of this spectrum is in frequencies not blocked by the atmosphere. at which point enough heat escapes immediately that the warming trend stops. now... i said this was a trick question. and i meant it. it's a nice tidy explanation. but if you look at the absorption spectrum of the atmosphere there are some holes. heh. both literally in the spectrum and in the above argument. this piece of the puzzle doesn't quite fit. also that thing we call weather, ie storms, are pretty efficient at moving heat from the surface to higher parts of the atmosphere where it's much easier for it to radiate away. hrm. now look at the absorption spectrum of water. ooo. water is transparent to sunlight and opaque to pretty much everything else. ah! it's the oceans that produce the bulk of earth's greenhouse effect. not the atmosphere.  ¶ 8:00 AM