Al Gore is confusing the AGW situation again. Now he points out that Venus has a very dense atmosphere that is 96% carbon dioxide (300,000 times the concentration on Earth), and the surface temperature is 570 F, ergo carbon dioxide is what makes the surface of Venus hot. Actually that is not the reason the surface of Venus is so hot. It could be pointed out that the atmosphere of Mars is also 95% carbon dioxide, though the pressure is only about 0.1 psi. Still that is 10 or 15 times the concentration of carbon dioxide in Earth's atmosphere. On Mars all of that carbon dioxide provides a "greenhouse effect" that adds about 4 or 5 F to the average surface temperature.

The heat transfer in the Venus atmosphere is complex. There are some phenomena regarding solar heat transfer here on Earth that everyone is aware of, but people may not have thought about it. Consider the Stefan-Boltzmann equation.

(alpha)(Area)(Solar Flux)=(emittance)(Area)(Stefan-Boltzmann Constant)(Tsurface^4 - Tspace^4)

For a flat plate both areas are the same if we assume the back of the plate is insulated, so areas cancel out.

Tspace is near 0 R so the term can be dropped. If the sun is shining directly on the plate, the solar flux is 443 BTU/sq. ft.-hr. Stefan-Boltzman constant = 0.173 X10^-8 BTU/sq. ft.- hr.-R^4. Then solve for Tsurface, and

Tsurface=[(alpha/emittance)(443)/0.173X 10^-8]^0.25 (in degrees R: subtract 460 to convert to degrees F)

For a material like the siver-backed teflon used on the space shuttle radiators (alpha/emittance)=0.1 approximately. Solving for Tsurface

Tsurface=400 R = -60 F (Thus the radiators will reject heat at 80 F, even when pointed directly at the sun.)

Now consider bare metal with (alpha/emittance) = 3, facing the sun at noon.

Tsurface=936 R = 476F

For a piece of metal lying on some insulation on the ground there is also convection to the air, so the metal won't get as hot as this calculation. But, if you put your hand on such a piece of metal, you will burn your hand. I've done it. Another more common example is to touch the top of a white car and a black car. The white car has alpha/e of about 0.25 and the black car has alpha/e of about 1.0. But you will be able to feel that the black car top is much hotter, though it won't burn your hand if you don't press hard.

The situation on Venus is more complicated than this, but it is also more complicated than just having a lot of carbon dioxide in the Venus atmosphere. Once again Gore is dealing in hype.

One of the disagreements between scientists regarding AGW on Earth is the amount of the greenhouse gas effect that is provided carbon dioxide rather than the much higher concentration of water vapor. (Everyone agrees that carbon dioxide absorbs infrared energy at around 2.7, 4.3, and 15 microns.) The total greenhouse gas effect adds about 60 F to the Earth's surface temperature. The AGW supporters seem to think that carbon dioxide is responsible for about 12 to 15 F of the greenhouse gas effect. Others think the effect is much less at 2 or 3 F. Also, adding more carbon dioxide is logarithmic rather than linear. But, how much temperature increase one thinks is currently added by carbon dioxide obviously affects how much would be expected as the carbon dioxide concentration increases. I think it is pretty certain that the lower estimate is closer to reality.