I've forgotten what the method was but it is within the realm of possibility today for a single wealthy individual to destroy the world at their whim.

IIRC it didn't require any fancy future tech or bombs. It just required the will with current tech. Like sending up 10000 balloons full of a certain kind of existing chemical into the upper atmosphere.

IIRC the article was about governments deciding they need to take planet wide effecting geo hacking steps for global warming but what if they're wrong. Following some of those steps it was clear that a modestly rich individual could implement some of them on their own.

I can't remember which website or podcast I heard this from. It could have been 80000 Hours or Making Sense or Slate Star Codex