Yes, but as long as we're having some fun with the concept: The problem with CO2 isn't the absolute CO2 in the atmosphere; most(?) of it was already there. It's

Yes, but as long as we're having some fun with the concept: The problem with CO2 isn't the absolute CO2 in the atmosphere; most(?) of it was already there. It's the changes caused by the added CO2. The problem with H2O wouldn't be the absolute amount, but the changes brought on by the added H2O. For one thing, it would rain pretty much 24/7 in Florida. :) (Yes, I know it's not at all that predictable.)