Launch giant rolls of toilet paper. Spread them out in low orbit. They will reflect light; ablate incoming space junk, and sequester carbon as well as stimulating the forestry industry. If we want to we could subsidize newspapers by having them print ads on them before launch.
Of course they won't last long, even low orbits are harsh. This will be an ongoing opportunity for several industries capable of making important campaign donations.
Strangely, I think I would be more okay with this than a longer lasting chemical- TP is predominantly lignin, of which the atmosphere already has the constituent elements. Only worry is stray chlorine, lead and other heavy metal contaminants absorbed into the source material from trees as they grew- but presumably the TP would offset whatever shenanigans those get up to.
Since it would break down and burn up upon reentry (or maybe just float down?) there might not be that much interaction anyway.
Compare that with the unknowns of longer-lasting particulates of sulfur and other nasties, the back-of-the-napkin math really doesn't sound that bad.
What's the math for this? How much CO2 per gram into low orbit, these days?
My naive assumption is that the amount of CO2 released to put them into orbit would be a net negative, since they'll eventually fall away, revealing the the now increased CO2 to the sun.
Of course they won't last long, even low orbits are harsh. This will be an ongoing opportunity for several industries capable of making important campaign donations.