Comment Water Vapor? (Score 1) 492
Admittedly I am out of my element here but there seems to be a couple of potential problems with this.
1. Water vapor is the most significant of the greenhouse gases.
2. Cloud cover prevents heat from being re-radiated into space.
I guess if you covered the whole earth with clouds it might reflect more sunlight and lead to a net temperature decrease. Not sure about that being a Real Good Idea.