Energy is really fungible, one of the most fungible commodities. Hydro can easily substitute for coal, oil, gas and nuclear elsewhere. This makes your defence especially weak.
Almost by definition, cryptocurrency requires spending useless energy. In electronic transactions as they exist today, you essentially only have to update the tables in two institution's databases (plus all the replication and backups that entails). A cryptocurrency requires everybody to record their transaction--and do a bunch of useless cryptography to to ensure that they do so.
Asking how much emissions it costs to mine the gold or grow the cotton to satisfy my paycheck is misleading. Exactly 0 joules were spent: no gold needed to be mined, nor coins minted, nor dollar bills printed to satisfy the electronic transactions to decrement a number at my employer's bank and increment the number at my personal bank appropriately.
I am not sure about Chinese miners being near hydro-electric some may be and some may be not, but over all its complete waste of energy.
When it comes to energy efficiency nothing beats centralized. I do understand the motivation behind decentralized, but you pay the price!
Hopefully Proof of Stake with reduced power consumption becomes a norm, but I am skeptical.
Several big Bitcoin miners are setup near or just being powered by hydroelectric dams or other renewable energy sources. And all of them of course target low costs, which a lot of times means that there's an oversupply of power in essence helping in some cases use energy that would go to waste otherwise.
You have to compare the gold or bank industry's to Bitcoin's mining emissions. Gold is constrained by the gold mines positions, uses oil a lot, unless someone does a proper study, all this articles are just sensationalistic articles by clueless journos hunting pageviews and likes.
Sidenote, funny how this is filled under "Currency Manipulation"