If you do not agree, please explain why.
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Absolutely. No scientific proof otherwise.
Not every gas in the atmosphere contributes to the greenhouse effect and the reason why has to do with symmetry of the molecules themselves. To explain this as simple as possible, molecules that are of the same pair (such as N2 and O2 which make up the bulk of the atmosphere at about 91%) when heated will vibrate in tandem allowing the energy to travel from low to high effortlessly. While molecules made-up of an odd number or differing atoms (CO2, CH4, H2O, N2O etc.) tend to have an oscillating dipole due to their differing masses. What this means is that when these molecules become excited there are moments where they'll 'flip' which will send energy down, in essence creating your greenhouse effect.
To your additional details: Your are correct that H2O is by far the most significant greenhouse gas in the atmosphere and is responsible for the majority of Earth's warmth. However due to its short lifespan (about nine days) in the atmosphere and the initial energy required to become vapour, its presence is more symptomatic of other forces working upon it ie. other greenhouse gasses, solar energy, atmospheric pressure, luminosity etc. H2O is a pretty dynamic GHG that is very susceptible to changes in the climate and responds pretty dramatically in some cases.
"..Sun radiates plenty of infrared and pours it into the top of the atmosphere, so CO2 can saturate from either direction, not just from the ground" I'm not sure what you're arguing here exactly.
As for the video, I'm not sure what she's arguing either. Ppm isn't a unit of measurement it's a sum-by-sum fraction of a particular fluid relative to all others within a dimensionless quantity. She's presenting it as if it's a negligible amount in total but when considering how massive an relatively dense the Earth's atmosphere is, it really isn't that tiny.
Edit: ".. I ask does every gas in the atmosphere heat due to absorption solar radiation of any kind, and there are many kinds of solar radiation that are NOT infrared."
Oh, well in that case the answer is predominantly a no. There are few gases in the atmosphere that absorb visible and UV radiation due to how short the wavelength's are. The only gas of particular note is O3, which absorbs and reflects UV radiation in the upper atmosphere and is responsible for protecting us against high energy radiation that is harmful to biological life. Here on the surface visible light travels unimpeded until it hits something and is either absorbed and re-emitted as longer wavelengths or reflected back into space. The only 'gas' that absorbs visible light is smog which is a noxious mix of air particulates and various gasses getting stirred up by the suns energy.
~ I thought your question was regarding radiation above infrared and its interactions with the atmosphere? Electromagnetic radiation is just an umbrella term referring to all wavelengths of light from radiowaves to gammarays. In regards to the Earth the vast majority of black body radiation is in the lower wavelengths (radio, microwave and infrared radiation). I don't see how a wiki article on black-body radiation disproves what I said or reinforces your argument.
But what makes the greenhouse effect significant is that more heat is trapped going out than coming in.
As I understand it, any radiation absorbed by sunlight hitting, say, nitrogen or oxygen is the exact same radiation that would be absorbed by the Earth's surface if the radiation made it that far instead. And radiation absorbed by the outer atmosphere will also be *re-emitted* more easily. So, in essence, while it will change the *distribution* of heat slightly, it will *not* cause any significant changes in the *overall amount of heat retained*.
But, a greenhouse gas lets through most of the incoming radiation (which is, in large part, visible and UV rather than infrared), but then catches much of the outgoing radiation (which is mostly infrared). So, the energy passes in to the center easily, but then has a hard time getting out. Thus, increased temperature.
edit:
But the key point is that a lot of UV and visible light *turns into* infrared light at the Earth's surface (more or less).
Picture it about like this.
If light is treated the same way going in as coming out--whether it's infrared light from the sun, or UV and visible light that is reflected rather than absorbed and re-emitted--then the presence or absence of a particular atmospheric component will make almost no difference in how much warming is caused. That's because, in essence, for every photon that's "trapped" (that is, slowed down, so that it raises temperatures before leaving the system) in the lower atmosphere, there will be another photon that never got that far, because it was absorbed by the upper atmosphere and immediately re-emitted into space. There will be little or no difference in total system temperature between a world with inert gasses and one with no atmosphere at all.
But, if light goes in in one form, and goes out in another, and part of the atmosphere is transparent to the first form but relatively opaque to the second, then that light will pass through to the surface without getting "caught" on its way in (and thus, without having any components immediately re-emitted to space), but it will get "trapped" on the way back out. This will lead to higher temperatures.
So what?
There are two points making your question irrelevant.
First is relative effect. Everything has mass, too, but there's a lot of difference between a liter of helium and a liter of lead.
Second, the increased greenhouse effect that is adding heat to the earth comes from the increased blocking and reradiation of earth's outgoing radiation, not changes in solar input.
not all gasses absorb heat , some gasses dissipate heat very well . So I have to disagree with this Question .
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If you do not agree, please explain why.
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