You also have to compare it against what its competing against, all those fancy bank buildings with 24.7 lights and ac, the staff to mantain the paper trail (their commutes, etc), the vast security forces and militaries there to secure it (military being the largest polluter), etc.
From what I understand, the growth of the network, especially when it piggy backs on layer two networks like the lightning network for btc means 99% of the transactions can operate in a non proof of work method costing little more than the servers used to run a popular website.
Its still sooooo early. The tech will evolve and competition is fierce for the best solutions. So long we dont try to regulate it to death and protect the status quo, its going to evolve in ways we are yet to imagine.
