After reading the above I've come to the conclusion that we really don't know what is the threat of global warming to life. I say life because unless it is at that level that things impact parsing out lessor threads conflict with other threads resulting in life changes rather than life disappears.
If we are talking about an event of a magnitude of changing to a Venus like environment, one that is incapable of supporting water, then we are talking about threat to all life which would be serious. Anything less one should expect something coming out the other side that works quite well in whatever life suitable environment results.
That is an entirely different question because we may only be talking about the extinction of man and like species or something similar. Man can't recognize such change because it isn't really relevant to life. Why work in something that is beyond what makes a species more fit than others? As long as man can get by, and that doesn't mean modern man with his modern technology, just some environment where men will still be top dog.
I argue that man can be top dog if he retains language and tool building capacities without the cities, farming, mining, and other capacities, including knowledge building. In the meantime other species will probably evolve to compete with us in this brave new world.
That, however is another story.
So put away your Freud-a-lators, semi-science speculations and the like. Focus on what we have that is permitting us to ignore oceans rising (we did it before about 60-80 thousand years ago), temperatures changing, oxygen mix changing, etc. We got where we are because we adapted to all that. We are multidimensional survival, fitness, machines. What is it about the current situation that threatens oxygen, temperature, sea level beyond what we've survived. There, you might find something to which we should be sensitive. So far I don't see it.
If you are only worried that we won't have what we have today you miss the entire point of evolution. Its important to us but its small change in the bigger picture.