Excellent news for the climate.
Most mining has already shifted out of China, and Bitcoin mining is a very small percentage of electricity usage on the scale of "all electricity usage" - there are plenty of bigger fish (the argument then turns, validly, to the usefulness of said bigger fish in comparison to bitcoin).
Sure, but in most cases people would, at best, be seriously inconvenienced if they were immediately banned. At worst, people would die.
If bitcoin was banned worldwide tomorrow, it would be an interesting story in the news and the internet would be furious for a while; there would be no significant real-life impact. It would probably be the most slam-dunk "obviously we should do this" environmental regulation in history; even things like "we should not put mercury in lakes" had significant downsides compared to banning bitcoin.