No trend in atmospheric CO2, he said.

[TellyKNeasuss]

Water lost to space? You mean H lost to space, and O combining with C, in that absence of a carbon cycle, likely. No oxidation process is necessary for the reduction, with sufficient incoming solar energy.

Whatever. It doesn't change the premise that the loss of water vapor in the atmosphere would remove the heating due to absorption by water vapor.

As for this nonsense (of yours about) "a CO2 molecule's gotta do...."

It was at least as good as your jokes.

...the question we were discussing was the "greenhouse effect". Which isn't exactly commonly thought of as the product of re radiation from within the atmosphere, is it?

It isn't?

By the way, I'm still waiting for an explanation of how reflecting visible light back and forth between reflecting surfaces generates heat.

 

[mhaze]

Whatever. It doesn't change the premise that the loss of water vapor in the atmosphere would remove the heating due to absorption by water vapor..

Nope, and it doesn't change the premise that no matter what atmosphere components were underneath that cloud layer, if it was 99 bar then boatloads of heating are going to occur, little visible light is going to get to the surface, and the atmopshere, having absorbed almost all the heat before it got to the surface, is going to be pretty hot.

It isn't?

By the way, I'm still waiting for an explanation of how reflecting visible light back and forth between reflecting surfaces generates heat.

Really? Of course we covered that, but maybe you missed it? Successive re emission at progressively lower spectral levels, is the method by which the visible light is converted to heat.

So now you want to define greenhouse effect as including the absorption of incoming energy, without any substantial contribution by the emissions from the solid surface of the planet?

A curious twist. Wonder what wikipedia would have to say about that.

 

[TellyKNeasuss]

Nope, and it doesn't change the premise that no matter what atmosphere components were underneath that cloud layer, if it was 99 bar then boatloads of heating are going to occur, little visible light is going to get to the surface, and the atmopshere, having absorbed almost all the heat before it got to the surface, is going to be pretty hot.

As I stated earlier, the atmosphere of Venus only absorbs two-thirds more solar radiation per m^2 than does the Earth's atmosphere. The combined heat from absorption of solar radiation and latent heat transfer in the Earth's atmosphere exceeds the amount of energy that Venus' atmosphere absorbs from the Sun. So, no, the atmosphere is not going to be "pretty hot" merely from absorbing "almost all the heat". And that's not even accounting for the difference in mass.

As has been pointed out by several posters, only an increase in pressure produces higher temperatures; static pressure does not change temperature.

Really? Of course we covered that, but maybe you missed it? Successive re emission at progressively lower spectral levels, is the method by which the visible light is converted to heat.

How can something that is reflected be re-emitted? Doesn't energy have to be absorbed to be re-emitted? Does a perfect reflector gain any energy from the radiation that is reflected?

So now you want to define greenhouse effect as including the absorption of incoming energy, without any substantial contribution by the emissions from the solid surface of the planet?

As far as I know, that's the standard usage of the term. In the Earth's atmosphere, gases at higher levels absorb energy emitted by gases at lower levels.

 

[TellyKNeasuss]

So now you want to define greenhouse effect as including the absorption of incoming energy, without any substantial contribution by the emissions from the solid surface of the planet?

A curious twist. Wonder what wikipedia would have to say about that.

Since you asked: According to wikipedia, "The greenhouse effect is the heating of the surface of a planet or moon due to the presence of an atmosphere containing gases that absorb and emit infrared radiation" Their definition says nothing about the absorbed IR having to be emitted from the surface.

http://en.wikipedia.org/wiki/Greenhouse_effect

 

[Trakar]

I don't think that we missed anything. 75 percent of the solar radiation is reflected, not absorbed. Do you have citation as to how much of the remainder is absorbed in the atmosphere rather than reaches the surface?

One thing the papers do clarify, is that if H2O and SO2 are removed from the equation, you get two results:

1) The atmosphere of Venus clears up (cloud layers disappear).

2) The greenhouse effect intensifies, and surface temperature zooms up around 900K

Thus we see that while the miniscule amounts of water and SO2 in the atmosphere do combine to become minor IR absorption amplifiers, their primary net effect is as a positive feedback actually reducing the overall much greater impact of CO2. What's more, we don't even really need to extrapolate from the Venusian atmosphere, we have some terrestrial experience that we can look to for some correlation. We can look at measurements taken in the 70s and 80s and see the impacts and correlations from the Clean Air Act's diminishment of SO2 and other particulates from substantive portions of our open-cycle emissions stream.

 

[mhaze]

Since you asked: According to wikipedia, "The greenhouse effect is the heating of the surface of a planet or moon due to the presence of an atmosphere containing gases that absorb and emit infrared radiation" Their definition says nothing about the absorbed IR having to be emitted from the surface.

http://en.wikipedia.org/wiki/Greenhouse_effect

Ok. And the definition excludes heating from the absorption of visible light, doesn't it?

So since we are not considering here the heating of the atmosphere from IR emitted from the surface, and since the 25% of visible light that goes through the cloud layer is somehow absorbed, where is the cause of atmospheric heating?

A. from the narrow and weak absorption bands of CO2 in the infrared
B. from the absorption of the 25% of visible light in the lower atmosphere

Only from (A) do you have greenhouse effect.

 

[TellyKNeasuss]

Ok. And the definition excludes heating from the absorption of visible light, doesn't it?

So since we are not considering here the heating of the atmosphere from IR emitted from the surface, and since the 25% of visible light that goes through the cloud layer is somehow absorbed, where is the cause of atmospheric heating?

A. from the narrow and weak absorption bands of CO2 in the infrared
B. from the absorption of the 25% of visible light in the lower atmosphere

Only from (A) do you have greenhouse effect.

Your point is? As I've mentioned several times, the mere 130 W/m^2 of solar radiation of all wavelengths absorbed by the Venusian atmosphere isn't nearly enough to cause the high temperatures found there. You can (and I'm sure will) drone on and on about the absorption of visible light, but it doesn't change the simple fact that 130 W/m^2 can't come close to supplying enough heat to warm Venus' atmosphere (the Earth's atmosphere absorbs about 4 times that much from all sources).

 

[BenBurch]

TKN, his argument is "Venus has no CO2 greenhouse because my Tea Party politics will not permit it."

 

[mhaze]

Your point is? As I've mentioned several times, the mere 130 W/m^2 of solar radiation of all wavelengths absorbed by the Venusian atmosphere isn't nearly enough to cause the high temperatures found there. You can (and I'm sure will) drone on and on about the absorption of visible light, but it doesn't change the simple fact that 130 W/m^2 can't come close to supplying enough heat to warm Venus' atmosphere (the Earth's atmosphere absorbs about 4 times that much from all sources).

Right, I will drone on about it because it is what is causing the effects we are discussing. That's your energy source.

You don't have any other energy source.

Your argument about this being a small amount - nope, it is a huge amount, and it is the CO2 absorption band fraction which is a tiny amount of that number. Further, you have apparently) neglected radiative balance in your argument and it does not stand when that part of the equation is brought into play.

 

[TellyKNeasuss]

Right, I will drone on about it because it is what is causing the effects we are discussing. That's your energy source.

You don't have any other energy source.

Your argument about this being a small amount - nope, it is a huge amount, and it is the CO2 absorption band fraction which is a tiny amount of that number. Further, you have apparently) neglected radiative balance in your argument and it does not stand when that part of the equation is brought into play.

The total amount of solar energy absorbed by the atmosphere and surface of Venus is about 150 W/m^2. The total amount of energy absorbed by the Earth's atmosphere and surface is about 239 W/m^2. 239 is larger than 150.

Venus's atmosphere absorbs about 130 W^2 from the Sun. The Earth's atmosphere receives about 530 W^2 from absorption from the Sun. absorption of Infrared radiation, and convective and latent heat transfer. 530 is larger than 130.

The average surface temperature on the Earth is about 288K. The average surface temperature on Venus is about 740K. 740 is larger than 288.

Venus' atmosphere has more mass than the Earth's. Therefore, it takes more energy per unit area to cause the same temperature increase on Venus.

 

[BenBurch]

TKN,

Never try to teach a pig to sing. It wastes your time and it annoys the pig. – Mark Twain.