I think you've misunderstood something. Those people are buying their own electricity...at their own expense. So, you want to bring arbitrary restrictions to electricity - as if we didn't have enough issues with net neutrality already.
Assuming bitcoin is using carbon poluting sources. Some of the bigger miners in China use hydro/dam energy. The miners in Iceland are using geothermal.
>The market could solve this problem properly if there were a global carbon tax, but unfortunately, there isn't.
"Solve it"? How so? Crypto mining is largely powered by renewables (40% according to one source in Sep 2020). It is a race to find the most energy efficient way create power to make it worthwhile to mine, which has some positive effect on society by driving innovation. No idea if that is a net positive, but this is not black and white issue at all the way many here are framing it.
> Crypto mining is largely powered by renewables (40% according to one source in Sep 2020).
That’s one source and less than half does not mean “largely” in standard English usage. More importantly, almost nobody uses Bitcoin so a key question would be how that’d change if usage could be scaled up to, say, even 0.1% of daily transactions.
For bitcoin to use an equivalent amount of carbon as visa per transaction, it'd need to be 99.9999% powered by renewables and visa would need to be 100% powered by fossil fuels.
We have solar power, hydroelectricity, nuclear power, wind turbines...if the mere fact of electricity existing has an adverse effect on the climate, I can tell you one thing:
The public? Something that benefits a few at the expense of the many is the canonical case for regulation.
(I don’t think we should ban or even really regulate Bitcoin. Not at this point.)