and the carbon footprint of mining is currently the size of Argentina's.
What is your source for this?
say that bitcoin mining uses 121 terawatt-hours (that is, 121 billion * 3600 watts) of electricity per hour.
Worlddata says that Argentina also uses 121 terawatt-hours in a whole year. I believe that's where OP got this information from.
...Carbon dioxide production is a far more important metric.
Bitcoin mining makes about
36.95 megatons of carbon dioxide per year, but don't consider the rest of the metrics - the e-metrics for individual transactions in particular are silly and make no sense. But we are doing
much better than even a couple third world countries.
I don't think it would be feasible to stop mining even after all 100% of the coins are generated, because without mining, how will you put transactions into blocks? There will be no blocks found, payments would come screeching to a halt, of course the hashrate will drop and so will Bitcoin's value down to zero without being able to spend any of it.