This feels overly specific. Implementing something like a Pigovian tax is standard practice where negative externalities are concerned. There is no need for an

This feels overly specific. Implementing something like a Pigovian tax is standard practice where negative externalities are concerned. There is no need for an outright ban if properly taxed. There are also much larger negative externalities to cryptocurrency than CO2. Ransomware payments are a clear cut example that a ban might not even address and are easy to tax.