The so called "environmental impact" of BTC mining has nothing to do with BTC mining. The BTC miners cannot be blamed for consuming electricity, which is was produced by burning coal.
i would suggest to clarify, miners that just use grid electric cannot be blamed.. instead its the power plants allowed to be on the grid that are to be blamed. grid users have no voting rights of the grid, they are just receivers/customers
but if there are a couple asic farm that bought land that has its own fossil fuel generators(on-site) then they can be blamed for purposefully using fossil generated electric. thy chose to buy fossil power plants as their source.. emphasis only a few asic farms. not a majority
most asic farms however actually have previously set up their asic farms in zones known to be powered by green energy(hydro, nuclear) so many do try to avoid fossil zone power that goes to the grid, although it does require asic farms moving to these prefered zones.
in short people mining from home states, where they cant afford the extra effort for moving to greener zones cant be blamed, but those that can afford to move to greener zones should be applauded for that effort
The "negative environmental impact" of BTC mining would be zero, if all BTC miners start buying and consuming "green energy" only. Green energy is getting cheaper year after year.
Yes, the BTC blockchain can't handle the same amount of transactions as the fiat payment systems. And so what? Bitcoin will keep serving as a "digital gold" rather than a digital currency. I don't see this as a problem. You have alternatives. Use them instead of BTC.
green energy has huge initial infrastructure costs to have power plants that are effective at covering future growth demands for decades. and so have alot of untapped excess initially yet to be used, but available to cover the progress of population growth over decades.
by asic farms tapping into this excess means it helps fund that initial infrastructure earlier than expected, thus reducing the cost over time. so by allowing asics to take up this untapped excess helps not just the environment, but the progress of expanding greener energy and making it cheaper for other too sooner