CapelDodger
Penultimate Amazing
Atmospheric CO2 concentration varies considerably - in one location, over the course of a year - downwind of a major urban environment - in a year with El Nino or without.
If you total all the areas downwind (?) of urban enviroments, it still comes to a tiny fraction of the Eastern Pacific influenced by El Nino/La Nina. Just to get some sense of scale.
Moreover, numerous environments hold low or negligible quantities of water vapor.
None of them over the oceans, which constitute about 70% of the surface. Of the rest, the dessicated area is a small minority. There's a desert band from the Sahara to the Gobi but it's well outweighed by the wetlands to North and South.
Therefore, it seems possible to look directly at various concentrations of CO2 in the air and what their effects are, instead of taking refuge in highly questionable computer modeling.
You can't stop the weather from intruding unless you consider the whole planet. Sorry, but there it is. Without doing the experiment in a greenhouse, anyway, which would rather negate the purpose.

