There is an article running around the web and in the papers with a bunch of far-out scientific ideas for global warming mitigation...adding iron to the sea, making artificial trees, having a man-made volcano. One of these ideas, out of the University of Arizona, is called a space-launched solar umbrella and is made up of a bunch of mirrors that reflect some of the sunlight away from the earth.
The first science fiction story I published was a collaboration with the very brilliant Larry Niven called "Ice and Mirrors." In that story, published in Asimov's Science Fiction in February 2001, Larry and I have evil aliens use the same exact device to freeze a planet. The idea for the mirrors was Larry's (all this was shortly after Kim Stanley Robinson wrote his Red/Green/Blue Mars series that had a single big mirror called a "soletta" warming Mars and so the idea may have kind of come from that - I really don't remember).
It feels kind of like Star Trek communicators and cell phones....maybe we'll get weather control from space using little mirrors. A great example of the way science and science fiction play well with each other.