planetary boundary

Climate change is on a fast track, a surprisingly fast, very fast track. As such, it’s entirely possible that humanity may be facing the shock of a lifetime, caught off-guard, blindsided by a crumbling ecosystem, spawning tens of thousands of ISIS-like fighters formed into competing gangs struggling for survival.
Furthermore, what if the biosphere is already under stress by “planetary boundary” or the capacity of the planet to support life? Then what?