A lot has been said about mining and about the electricity consumption of the activities related to bitcoin mining. However, I have thought of the alternatives and how other systems produce not just energy waste, but also plenty of useless work and "human waste".
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?
I doubt if some one say that bitcoin is bad for the environment but if we really expect 100% sustainability and environmental friendliness from bitcoin we all should agree that the current way of mining bitcoin should be improve by considering more greener and sustainable paths because as the first digital currency world expect more effectiveness, efficiency and sustainability from bitcoin and it is easy to gain by making small changes