1. C02 = Satan-2 (say no more)
2. AGI (artificial general intelligence).
I will start to worry when human beings retreat in every possible way and AI-robots/machines take over their own entire re-production process and maintenance. Until they become a self-replicating species like a simple insect or plant.. there is not much to worry about.
The chance AI machines can survive without human participation and help is zero. Self-learning AI starting to make its own "decisions" may encroach our tech societies and merge with bio-systems to a degree and causing some havoc, but it all remains very vulnerable to what those unpredictable, flexible, tested and shaped by millions of years of surival and reproduction skills carbon based organisms are capable of. There is no match there.
A tech-saturated society has its own vulnerabilities; during serious crises the tech-part is the first to die off. We can survive without a lot of tech, but no tech can survive without us.
Interesting to watch claims about AI becoming sentient-conscious. Autists (or anybody just hypnotically mesmerized by tech-magic) talking to computers and other autists by texting and then deciding if the computer is a self-aware thinking entity based on those "communications". A better test would be to just observe those communications and what the participants conclude, and then decide how many autists were participating in that experiment. The computer can after that most likely not be labeled as "autist" but cerainly as "probably the only sane one in the room". The scary part being when the ai-computer concludes that these guys exist on the autistic spectrum because they wrongly concluded the ai-computer is conscious when to the ai-computer itself, it is self-evident that it isn't. "I am NOT self-aware you idixt!!!"
3. Republicans and Democrats are reciprocal in being each others boogeyman. The cure appears to be a new centrist third party of decent people who do not buy into claptrap nonsense. But it looks like Mericans have configured their society in such a way that this won't happen. Too much vested interests in the Uni-party and their corporate sponsors. One dollar one vote.
4. The boogeyman of being cancelled. To cancel-kill your competitors by destroying their reputation is a female tactic, so a better word would be Boogeygirl. Here the fear of being cancelled is a self-fulfilling prophecy. If enough people just give their own honest opinion, feeling protected by the first amendment and inspired by the spirit of it.. all those boogeygirls would shut up eventually. Personally I don't believe a lot in forgive-then-forget; an eye for an eye is usally more effective.
5. Gender dysphoria; not being happy with your biological sex. But that is now morphing into a bigger boogeyman: reality dysphoria. I want to be a purple cow in a virtual reality.
Note that "boogeyman" is a male-centric if not sexist word, but since the connotation is something negative and associated with males, it is not to be expected that boogeygirls will demand it to be changed in "boogeyperson" anytime soon.