I'm far from an eco-hippy and my lifestyle will never be undamaging to the environment (I fly to other countries too often and enjoy technology made in extremely polluting and harmful ways) but at least I'm aware that I'm doing damage and trying to offset that as much as I
reasonably can.
The eye opener for me was this xkcd:
xkcd.com
And the worst-case "current path" at the bottom turned out to be too optimistic itself, because that was over 4 years ago, based on 2013 and 2014 data. The rate of icecap melting and ocean temperature have turned out to be far worse and more rapid that Randal Munroes predictions of four years ago. We, as a species are fucked. The question is not if, but when it will become really,
really bad. I'm comfortably middle-aged so perhaps I'll live out my lifespan relatively unscathed. I can't say I believe that will be true for the younger generation here on TPU.