[ToddT]

Renegade, read an acticle recently. had to with providing a sun screen. But un like your idea this is far practical.
First it has to do with, the fact theres to components to the global warming story. One is the obvious increased CO2, but a large part of the source of CO2 also emits large quatites of parcticlate matter. (which affects ice and water drop formation in the atmosphere)The CO2 increases the amount of heat trapped, but the parciclates reduce the amount of sunlight reaching the surface. the US and Europe have made some good progress on partciacale ruduction, but china and india have currenlty offset it. the later 2 countries now starting to take steps to clean up in that area too.
This is where the Sun screen comes in as the parcticle pollution is cleaned up more solar engery ill reach the surface and the CO2 issue will reaaly make itself felt. So the This guy propose making around 10 million (can't remeber exact size but not huge) refecltor satlites place in the Earth Sun lagrange point. using nothing more than high quaalty glass (are something simialr that want darken to quickly) to block about 2 to 3% of the light reaching earth, the idea being to buy time to fix the co2 problem.
he refered the the Co2 nad particulate issue as a Faustian deal.