" "CO2 pound for pound [or in terms of liquid or gas volume] is not a substance which is as effective greenhouse agent as H2O"

You didn't want to bet me on global warming - how about a bet as to the accuracy of that statement? "

As said this was sort of my premise or starting point of my post. Or a summary of what I going to do- or roadmap. When I wrote it, I had intended to look at the difference between "pound for pound" and volume relation of water and CO2, but that was sort of dropped along the way [to some extent, but also I hadn't finished my "point" or post, rather it was situation of posting what I had written so far, or saving it on Notepad and completing at a later date].
There is of course a difference in comparison with density and percentage or ppm [and I think it's safe to say I made an error in comparing Mars' atmosphere and Earth's- perhaps I'll get back to correcting that]. This is a pretty good site with information on this subject:
http://www.uigi.com/air.html
"water vapor is less dense than air (the molecular weight of water is 18.02 vs.28.98 for dry air)"
"CO2: 44.01 [Molecular Weight]"

So in terms of density CO2 is more twice as dense as H2O and in terms of comparing dry air, CO2 is 1.5 times as dense.
Which means if H20 is equal in effectiveness to CO2 as a greenhouse in volume, H2O is more than twice as effective as a greenhouse gas in density or weight comparisons. Perhaps this also explains CH4. Let me check it molecule weight: 16.043. About same as water [CO2 is 2.7 times as dense]. And since Methane is generally stated in terms tons, you could say it was about 2.7 times as effective as greenhouse gas as CO2.
Of course, it's more complicated than this. But as I wrote it, you would have probably lost the bet.
Now, what I was really interested in was how H20 and CO2 compares terms of volume, as far as how effective they are as greenhouse gases. This is more complicated. In quick summary one has the reflective or absorbtion characteristics both to incoming solar radiation [which includes infrared as part of this spectrum] and you infrared radiation from the Earth which reflected or absorbed. With visible light water is highly reflective and transparent. [A calm mountain lake reflecting the image of mountains shows it's reflective nature and having light being able to go through a hundred feet of water.] And of course clouds and snow which are highly reflective. But in regards to the greenhouse affect the interest is in infrared light with the near infrared being most infrared energy from Sun coming through atmosphere and then the middle infrared being the radiated from heated earth surface.
[To be continued]