I recently 100%'d Terra Nil, an excellent indie puzzle/strategy game about ecological restoration. It rules and is extremely environmentalist. The premise is that you are responsible for restoring habitats ruined by human civilization. There's never any background about exactly what happened (because you know and see it every day) or how society got to the point of dedicating itself to fixing these problems; it simply takes for granted that, eventually, something is going to be done (a bit of a "communism is inevitable" message, imo). The game is not very difficult, but I found it rewarding nonetheless. It's also just a chill af vibe.
I'm also a big fan of a very different series on ecological restoration: Horizon. It goes a bit underdiscussed, but the A plot of those games is that capitalists will destroy the earth in the worst way imaginable, but that no crisis is final, and we can, eventually, undo the damage we've done. You fight big robots and
Horizon Forbidden West spoilers
kill the would-be immortal trillionaries who caused the problem in the first place :::. Though they're the epitome of big bombastic, cinematic PlayStation games, I love that shit and I'm all about the message the games are sending. They are, ultimately, optimistic.
What are some other games where environmentalism is the core theme? Particularly if what they depict is the good side of humanity's interaction with the environment: fixing the shit capitalists broke. That's the vibe I'm after most of all.
I've been meaning to get into Timberborn. You play as intelligent beavers who have suceeded humans and are committed to not making the same mistakes while building their civilization.
Timberborn is very fun, the way the water plays a major role is nice. Though I've found the fun short-lived - right now once you've done a few games it's repetitive after. Hopefully new stuff will help with that between now and the release.