> It's also unlikely that all humans would die out even from severe climate change given our current technology.

Up to a point, you could artificially sustain small populations (climate-controlled greenhouses and habitation). But there's a limit. We are not able to recreate the whole biosphere yet.

Which is all the reason to remember that, whatever we do, we absolutely cannot break our civilization's ability to maintain existing level of technology and improve on it. If we do break it, we're done. The Gulf Stream shutting down would be tough, but survivable. Global economy shutting down would be game over for humanity, preceded by unprecedented amounts of suffering.

> You could say that saving the environment is just saving the current set of humans, or our modern way of life. It definitely sounds much less noble when put that way though.

If you compare "our modern way of life" and the promises ahead to past millennia of humanity, it actually does sound very noble. I wouldn't wish medieval or ancestral life on my worst enemy.