I don't buy anything new (only second hand), I ride a bike, I don't eat meat.

The environemental impact should be assessed against how much we need it. Bitcoin show absolutely insane impact for zero pratical usage : pure greed and speculation.

Eventually, there will be carbon tax for any impact we have. We'll need to choose where we put each our of individual carbon budget.

When you will need to choose between moving around / eating or mining bitcoin, I doubt you will care about the later.