Cheers Richard,
Some good posts.
I have a question regarding your following statement:
"It has not even been established that CO2 increase actually does increase the temperature of the earth."
If CO2 reflects longer wavelength solar radiation (the type that leaves earth) then isn't the relationship relatively simple?
The more CO2 in the atmosphere - the more heat retention.
If we have raised CO2 levels (and we are not including any other greenhouse gas here) by 5%, then why is it not reasonable to think that we have raised temperatures?
I think you said in another post that water vapour has such a potent greenhouse effect that it dwarfs CO2's contribution into insignificance, but I don't think the jury is entirely in on this one because Earth's thermal radiation is greatest in the 8-18?m band where water vapour is a particularly weak absorber. CO2 blocks in the 12.5-18?m band and the rest (8-12.5?m) is picked up by methane and tropospheric ozone etc. Also the presence of CO2 increases absorption by water vapour.
Even the most sympathetic research still gives CO2 a 5 - 10% stake in radiation absorption.
CO2 is clearly very significant as a greenhouse gas.
You can argue around other evidence as much as you want (i.e. paintings showing lakes that used to freeze and don't today) - much of it can be interpreted to suit people's initial beliefs and some of it seems to clutching at straws, but the basic facts seem to me to be incontrovertible.
1. CO2 traps heat (proven).
2. We are adding CO2 to the atmosphere (proven).
3. Therefore more heat is being trapped. (and this corresponds to point 4).
4. We know the global temperature is rising.
Now your bone of contention here seems to be a hypothesis that there is an upper limit to the amount of CO2 in the atmosphere that can be effective at absorbing radiation . This is not universally accepted.
Unless you can point to something definitive.
Blacknad.
