I'll press your buttons here by positing that if "we" (humankind) are too dumb to self-regulate our own childbirth output, too dim to recognize that we are polluting ourselves and neighbors out of sustainable existence, we are, in fact, a ridiculous parasite on this Earth and that the planet on which we live will simply slough us off—as it well should—and will bounce back without evidence of we even being here, come two or three thousand years. Your thoughts (in as much detail as you wish)?I would recommend reading my "the next 50 years" piece here. Basically I think that
 climate change, which in this case genuinely is caused mostly by humanity, 
is just one part of the environmental problem. Overfishing, toxification of 
the seas, pesticide use, weedkillers, prescription drugs in water,
 fracking, continued air pollution, toxicity in food, destruction of animal
 habitat, attrition on bee colonies—all this is converging. And we'll be 
facing the consequences for several hundred years.

I believe humanity will
 survive, and it won't be surviving like Road Warrior or the Morlocks from The Time Machine, but I think we'll have some cruelly ugly social consequences. We'll have famines the like of which we've never seen before, along with higher risk of wars—I do predict a third world war in the second half of this century but I don't think it will be a nuclear war—and I think we'll suffer so hugely we'll be forced to have a change in consciousness to adapt.