Here's a fun comparison for you:
- One study [1] estimated that 70B kWh were required to run the Internet, at an estimated cost of ~$7B annually assuming 10c/kWh (which is probably high);
- One report [2] estimated the energy consumed by Bitcoin at 121.36TWh, which is 121.36B kWh.
So assuming these numbers are remotely accurate, which is a big "if" I'll admit, more energy is spent on Bitcoin than the entire rest of the Internet infrastructure.
Other commenters have asked variation of "once [coin] moves from PoW to PoS, what will [no coiners] complain about?" That's easy: not the (essentially pointless) energy expenditure (and resultant carbon footprint) obviously.
[1]: https://www.forbes.com/sites/christopherhelman/2016/06/28/ho...
[2]: https://www.bbc.com/news/technology-56012952