To have a network that can ensure the completeness of transactions, the global accessibility and all the features that bitcoins, and many alts, have at the moment, would probable produce a huge carbon footprint. Just think of the VISA system or the banking system... the amount of people working on it, the waste of commuting to works, the infrastructure.
Thinking of all that, would you still say Bitcoin is bad for the environment?
"Production" of bitcoin is no different in terms of electricity consumption from any other production capacities. Perhaps it is even more "environmentally friendly". We live in the industrial era and it is impossible to imagine our life without production capacities .