| Final-Fan said: Sqrl said: The water vapor vs C02 issue was run over by someone who sounded like they knew what they were talking about and nothing more. The fact is that water vapor is still the single largest net contributer to warming via the greenhouse effect despite its ability to regulate itself. Final-Fan said: Whatever its total share of contribution to the overall greenhouse effect, it sounds as if its atmospheric levels advance and retreat in lockstep with atmospheric temperature. Therefore, other greenhouse gases -- such as CO2 -- that are not completely tied to atmospheric temperature can exert upward (or, by their lack, downward) influence on the overall greenhouse effect that water vapor by its nature cannot. Am I missing something, or is there dispute over whether atmospheric water vapor is a strict function of temperature / temperature change, or what? [edit: Now, I do recognize that CO2 has an apparent tendency generally to rise and fall with temperature due to the oceanic phenomenon you mention over geological-scale time periods, but it still has a lot more independent movement on the level of tens or hundreds of years than water vapor does from the information that I have seen. In fact, I hear that even the most drastic change in water vapor would reassert the temperature-dictated equilibrium in 50-70 days. Higher in the atmosphere this would probably take longer to even out but the short reaction time is remarkable compared to carbon dioxide. [ http://www.realclimate.org/index.php?p=142 ] |
Not sure what I am missing but I'm honestly not seeing what you're driving at.
In any case the point I am driving at is that the human impact is pretty negligable.
But if we remove water vapor:
 |  |
And a better look at these breakdowns:
 |
|
 |  |
 |
So really the only thing Humans contribute to in a meaningful way is the category of "Other" which is only 0.007% of GHGs by concentration and 1.4% by effect, and that is after you remove water vapor. You could probably make a case that we contribute meaningfully to Methane also, but still that only accounts for .471% by concentration and 7.199% by effect.
To be fair this data is probably out of date by now, but I don't have a huge list of bookmarks to work from or anything so I just did a google search for global warming and water vapor and used the first data I found that looked credible and had a good credits section.
It appears to be from 2000 which is recent enough to be at the bare minimum a good indicator of how things are, even if not 100% accurate.
Edit: A quick weighting of everything shows that not including water vapor, humans are responsible for 5.5% of warming due to greenhouse effect. Considering that even the most diehard pro-GW scientist won't say that the GHE is responsible for all climate change I think 5.5% of a smaller portion is quickly getting into the territory of negligable.
But even then I still think there is reason to doubt that the current warming is related to the GHE in any meaningful way just based on the NASA satellite data.
 |
| To Each Man, Responsibility |
