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What is your source of information for this?
The 4.3 micrometer band is what is responsible for the runaway global warming on Venus... it radiates a lot of energy at that wavelength which gets absorbed and re-emitted back to the planet.
That is within the band we established earlier, corresponding to the coldest temperatures ever recorded, but a long way from the temperatures we consider 'normal'.
What is your source of information for this?
What wavelengths does an asphalt parking lot radiate? The sands of a desert heated by the Sun all day long?
The more CO2 (and other GHGs) there is in the atmosphere, the more heating of the atmosphere by both incoming and outgoing infrared.
You seem to have a bit of misunderstanding of what blackbody radiation is. The blackbody "temperature" is that wavelength at which the emission of radiation is maximized. It doesn't mean that it is the only wavelength which is emitted. Looking at the image below you can see that a temperature of 450ºC (723ºK) has a peak emissivity at about 4µm but it also is emitting at a wide range of other wavelengths, as do lower temperatures. Wavelengths which will be absorbed by CO2.
hence if the CO2 greenhouse effect is responsible for the high surface temperatures, which seems likely to me, it would be because of the 4.3 micrometer absorption band.
Yes. They get pretty hot don't they? Where do you think that heat goes? The more CO2 there is the more of it is captured by the atmosphere instead of radiating back into space. No one is saying that Earth will get as hot as Venus. But it doesn't have to for the climate to change dramatically.
That depends on their temperature. You know that.
26 gigatons (a year of CO2) is one hell of a loogie.
If I spit in the ocean, I raise the sea level.
You seem to have a bit of misunderstanding of what blackbody radiation is.
Where do you think that heat goes? The more CO2 there is the more of it is captured by the atmosphere instead of radiating back into space. No one is saying that Earth will get as hot as Venus. But it doesn't have to for the climate to change dramatically.
26 gigatons (a year of CO2) is one hell of a loogie.
Then you are simply wrong. There are only a couple of (infrared) wavelengths at which CO2 does not absorb radiation.
I simply state that it ONLY absorbs the portion of radiation at 15 um, which is a tiny percentage of the entire radiation spectrum.
What about the next CO2 molecule it encounters? That's why more CO2=more heat. The heat is retained because the radiation bounces around between GHGs. There is also the fact that a "hot" CO2 molecule which comes into contact with any other molecule will transfer heat in the form of kinetic energy.
The heat is radiated back into space. If a 15 um wavelength of that heat meets up with a molecule of CO2 (or water vapor) it will be absorbed and re-emitted in a random direction. That's a 50% probability that it will return to earth (assuming a low enough altitude for the planet to be considered a plane... just to take care of any nit-pickers) and add to the heat received.
Yes. But there is still energy there. Energy which CO2 is all too happy to absorb. And it will keep absorbing it until it peaks and emmits (when it will begin absorbing again) or bumps into another molecule of, say nitrogen or oxygen, and heats it up.
Incidentally, the hotter the surface, the farther the peak wavelength is from the CO2 absorption band, and thus the smaller the percentage of energy in that band.
People have used Venus as an example of how atmospheric absorbtion works. Unless you are saying that people have said "If we don't do something Earth will be like Venus!"
People have used Venus as a scare tactic to get public acceptance of global warming (I think Al Gore used it in An Inconvenient Truth).
And the percentage of CO2 is rising, steadily. Are you really trying to make the point that it doesn't matter how much CO2 is in the atmosphere? That it won't cause a temperature increase? That CO2 cannot affect radiative forcing?
26 gigatons is 0.00052% of that. Wow... perspective...
Then you are simply wrong.
What about the next CO2 molecule it encounters?
Yes. But there is still energy there. Energy which CO2 is all too happy to absorb. And it will keep absorbing it until it peaks and emmits (when it will begin absorbing again) or bumps into another molecule of, say nitrogen or oxygen, and heats it up.
People have used Venus as an example of how atmospheric absorbtion works. Unless you are saying that people have said "If we don't do something Earth will be like Venus!"
And the percentage of CO2 is rising, steadily.
No. It is the absorption spectrum for CO2.
Your image has nothing to do with CO2 absorption., It is the radiation curve for different blackbody temperatures.
Really? Then why does the air get warmer when the Sun is out? What heats up all that nitrogen and oxygen?
As far apart as molecules are in the atmosphere, it is unlikely that kinetic energy is going to transfer in the microsecond or so between absorption and re-emission.
We aren't talking about a flood.
How long have i got to spit in the ocean to flood New York City?
If CO2 levels get high enough to kill us the world will be a very hot place.
If we lose all natural CO2 sinks and continue pumping it into the air, then we will be in serious trouble. Not from the temperatures, but simply because we will all asphyxiate before we can realize it's getting hot.
Originally posted by TheRedneck
I assume you will agree with me on one point here: the ecosystem is extremely important to reabsorbing CO2 both to maintain a reasonable atmospheric level and to produce sufficient oxygen from that CO2. I support maintaining the rain forests both for their CO2 sink properties and to preserve the variety of flora and fauna indigenous to them. The oceans, however, specifically plankton, are the greatest CO2 sink and oxygen supplier of all. So far I see nothing that is endangering oceanic flora.
TheRedneck
No. It is the absorption spectrum for CO2.
Really? Then why does the air get warmer when the Sun is out? What heats up all that nitrogen and oxygen?
We aren't talking about a flood.
Yes. I know. There are three major peaks with absorbtion across the spectral range. When the linear scale is used the lower absorbion amounts disappear but they are still there. If the upper limit could be adjusted you would see them. You said there is only absorbtion at 15µm.
Whoops, was looking at the wrong image... try setting the resolution to linear instead of logarithmic:
What is conduction if not a transfer of kinetic energy from one molecule to the next? Or are you saying that only air molecules which contact the ground get heated?
You're talking a completely different process. Conduction and convection instead of radiation.
Sort of like Venus then?
It's called an analogy.
You said there is only absorbtion at 15µm.
What is conduction
Sort of like Venus then?
Slight yes, irrelevant no. They represent absorption of energy.
The reason the absorption at other wavelengths doesn't show up on a linear scaling is that it s minuscule and irrelevant.
Now that is irrelevant. We aren't talking about earthquakes we are talking about the absorption of energy.
Every day on earth, there are hundreds of earthquakes so small they are never felt, and probably thousands so small they don't even register.
An ad hom? I don't "expect" much from anyone but I find it surprising that you would resort to such.
I expected much better from you, Phage.
You didn't answer my question. Isn't conduction the transfer of thermal (kinetic) energy? Didn't you say previously that such an effect is not worth considering in the atmosphere? How does an atmosphere dominated by nitrogen get heated by sunlight?
A method to try and discredit facts shown... apparently. See above.
Slight yes, irrelevant no.
Now that is irrelevant.
An ad hom?
You didn't answer my question.