Thinking about the impending environmental apocalypse just now, I’d say along with basic skills like farming and building etc, one of the most important things in a post enviroapocalyptic tribe is chemical science - since the water will be contaminated and will need cleaning thoroughly before it can be used for most things, the soil also will be contaminated and need some kind of sterilisation before it can used for farming. Chemical science is also useful for things like medicine, general hygiene, and material science - which would be incredibly important for rebuilding society. Anyway, just a quick take lol.

We're literally on the cusp of the eco-collapse of our civilization and the most powerful country in the world is arguing about which old white dude they should put in charge. Old white dudes are the reason everything's about to go tits up. I hope the rich enjoy watching the world burn to an unrecognizable crisp, sink, implode, starve and die off. Hope those billions make a nice fan before they become kindle.