This plan reminds me of a book by Piers Anthony called “Rings of Ice”. Things didn’t work out all that well, the Earth ended up getting flooded with all the comet ice that was used to build the rings.
The idea in sounds too close to the ice ring idea to me. Putting lots of little hunks of stuff in orbit to me sounds like a big mistake. Wouldn’t the rings be right where all of our telecom satellites are at right now? Plus as it might light up the night time sky as much as a full moon, wouldn’t that have an effect on the animals (and us!) that live here?
As long as we’re taking about potential bad things to do to our home world, what about building shadow squares? At least those would be farther away from the Earth and thus out of the way of most things we put in to orbit. We might figure out a way to turn them off or somthing if they end up working a little too well…
Now, if someone wants to build a sun screen to put over Phoenix I’d be all over that. It’s &%#% hot here!
Space Ring Could Shade Earth and Stop Global Warming