As the price goes up it's worth it for miners to spend more to mine a coin. Even if it costs them enormously in energy costs.
Will they? Guaranteed.
As long as someone who wants to better their finances can make a fortune destroying a common good at least one psychopath will do that.
What can we do? Treat Bitcoin like we (should) treat the heroin trade. Folks want it, suppliers are getting foolishly rich off it, and it does absolutely no good.
Stop adding it as a checkout option like it's not a planet-killer.
And for godsakes stop letting anyone refer to the future promise of blockchain as a beard for BTC. If there were any other use besides burning Earth to a crisp we would have found it by now.
But this analogy may unfairly malign heroin, which for all its downsides, has probably brought the world more joy than Bitcoin ever has.