It's estimated that Bitcoin uses the same amount of energy as the entire Internet. Just to put that in perspective that's roughly 2% of all the energy generated by America every year.
America produces roughly 14,000,000,000,000 pounds of greenhouse gases in a year and 2% of that is 280,000,000,000 pounds...
The internet is around 40 times bigger than crypto as a whole. Feel free to check it and tell me if I missed the mark.
However, Buttcoin still eats a disgusting amount of electricity, being 2.5% of the whole internet. All the while, its only utility has so far been to create a completely unregulated commodity market that is unsurprisingly dominated by private equity doing pump and dumps.
The interesting thing someone brought up in that discussion though is that half of all consumer internet traffic is ads. Which is scary, and I don't know (or rather do exactly know) why we don't talk about that.
It's not outlandish if you know that mining Bitcoin basically means to waste electricity. The more electricity you use, the more Bitcoin you mine.
Bitcoin mining consists one brute forcing the inverse of a function that doesn't have an inverse. You just try every number and if you're lucky you get paid.