Could we use this against global warming? Artificially put something in the atmosphere that bounces part of the sunlight back?
Many people have proposed putting sulfur dioxide into the upper atmosphere. It looks relatively easy and could potentially be within the means of even poorer countries like Bangladesh which have a lot to loose from rising sea levels. But we can't predict exactly how it would turn out and it would certainly make ocean acidifcation worse so it's very much a desperation play.
Whether it might be uni- or multilateral is also interesting, given the possibly serious effects on e.g. agriculture in "downstream" geographic regions. It's not much of a stretch to imagine it kicking off some kind of war.