I recall a proposal to put sulfate particles (I think!) in the upper atmosphere, sort of like what happens with a big volcano, to try cooling things off. The downside is you have to do it constantly, the upside is that if you don't, it fades relatively quickly. So we could try it out on a pretty large scale and stop if we don't like where things are going.

But that's from memory, and I could be recalling the details wrong.

A lot of that technology relies of aerosols which would exacerbate the ocean acidification process. Get engineering is really hard to get right

Yes, you need to get the SOX into the stratosphere, so it doesn't rain out so fast.

This is probably what we will end up doing because it is the only one that is really viable without insane energy/time requirements. Everything else proposed would require an engineering project many many orders of magnitude greater than anything humans have done before.