My prediction: a country which has the political and technical ability to do so and is located somewhere where global warming starts being a major threat to it. Likely candidates: India and neighbors (wet bulb events depopulating large area) or China (inundation of the biggest population centres). This country eventually says "fuck it" and just does it, international opinion be damned. Everyone else in the world will proceed to performatively freak the fuck out. But, they'll all be watching closely and if it works, they'll all be doing it fairly soon. Again, if it works, in the eventual biopic, it'll be mentioned as an aside that they weren't 100% sure if the atmosphere would be destroyed or not, but they forged ahead.

The good news, since an internet forum's commentariat opinion isn't relevant to whether it happens or not, is that humanity is a couple of teratonnes into a 200-year experiment of many kinds of atmospheric modification and nothing critically non-linear has happened yet. Though we certainly don't have many sigmas of confidence that it isn't going to go non linear (but in the "hot" direction) at some point!

We're even doing a cute little cross-over trial specifically on atmospheric sulphur dioxide injection (just entered the second placebo phase)