I've heard some talk about a CO2 Coin before (one where a coin is mined by carbon capture). I'm sure there are all sorts of reasons why it would not work, but it would be the only kind of crypto I'd ever be interested in owning.
Not sure how you'd decentralize a physical process though.
And if there's a centralized arbiter validating people's capture results, then you've just invented a centralized currency? Why have crypto at all? It sounds like carbon credits (with all it's failings) with extra steps.
And if it didn’t fall foul of that and if CO2 was over captured then most life on earth would die.
This is known as the oracle problem and is actively being worked on.
It doesn’t try to sugar coat things and I appreciate that.
There are non-proof-of-work cryptos already out there.