1) Short of blocking communications and/or electricity, there is no technical switch you can flip to ban something that can be decentralized like Bitcoin mining

1) Short of blocking communications and/or electricity, there is no technical switch you can flip to ban something that can be decentralized like Bitcoin mining. That's why I used the word technical above. We're in agreement that you can actually try to ban Bitcoin mining by jailing/shooting/seizing/destroying various people and things, I just don't want to do that. 2) We're probably going to disagree sharply here, but I don't believe that climate change is causing clear and present harm. And if it was, nuclear energy is the solution to it, which many environmentalists desperately reject to the point of destroying their countries. I can't take climate change peoples' ideas seriously when they reject the only workable solution to the problem they claim will cause great harm. 3) PoW is a proven system that has been proven to work, no pun intended. PoS solutions are extremely interesting, but have security and centralization concerns and have not been proven as workable in the same way as PoW. Going from PoW to PoS is not necessarily a magic solution for anything and might ruin something good for humanity. Maybe Ethereum pulls it off and there's no long-term changes or problems, but nothing has been proven yet.