I dont think mining contributes to global warming.
People usually forget the following fact:
"Fiat requires commercial banks, central banks, ATMs, armored cars, hundreds of thousands of employees, among other things to work. The central bank, in this case the FED, does not magically distribute the US dollar to every person in the country at their doorstep."
This is interesting, because even mining methods can be solved to decrease energy consumption. Also blockchain can help at the distribution of renewable energy, using smart contracts. Other applications of blockchain can also contribute for business and generally, to the democratization of the global economy. I see more pros than cons to society, if you balance !