Smaller than the energy required to run Ireland, unlike bitcoin. An algorithm designed to be wasteful in energy wasting energy is not something we should be shocked at.
[0] https://en.wikipedia.org/wiki/Energy_usage_of_the_United_Sta...
And yes, the U.S. military should massively downscale.
We're all focusing on Bitcoin as if killing it would stop global warming or something. There are dozens of different things we could be criticizing when it comes to pollution.
Global climate change won't be slowed or stopped by a single silver bullet. It will take reduction in many, many areas combined, and many of those are already underway, have been underway for years now.
Meanwhile, all of those savings are being offset by wasteful-by-design crypto mining that benefits extraordinarily few people. So yes, in addition to the many, many, many reports on various other major contributors to ongoing climate change, it's time to talk about crypto mining, too.
If we are to waste time talking about polluting classes, let's focus on the big ones first. Naval transport, coal power plants. These should be regulated first.