[gherkin0]

> The problem with this is that once we've reached a "perilous level of global warming", it is quite possible that there is no way back.

IIRC, there have been significant periods in prehistory where there were no ice caps, and technically we're currently in the middle of an ice age [1]. That's not to say that the effects of global warming won't cause severe stresses on our current ecosystems and civilization, but it's an overstatement to say "there's no way back."

[1] https://en.wikipedia.org/wiki/Quaternary_glaciation

[mikeash]

There's always an implied "in a timescale that's meaningful for human civilization" in these things.

Of course the Earth can eventually recover, but if it takes a million years it might as well be never for the purposes of this discussion.