Everything I have read leads me to believe the maximum, long term carrying capacity for this planet is about two billion humans. We have massively overshot this target and are consuming mineral resources at an unsustainable rate. Every "fix" such as renewable energy sources merely shifts the finite resources being consumed. I doubt humans will go extinct in the next millennium, but other than zoos and game preserves all large mammals will. Just as they were once wiped out of the Americas by early humans. Humans won't go extinct, but a massive die-off is coming. We blithely ignore the reality of the fact that we are devouring the last of the easily obtained carbon energy sources. Fracking has given us another twenty to thirty years to drive our SUVs and heat our homes to 72 degrees, ignoring the fact that Americans consume 35% of the world's resources for 5% of the population. Enjoy the party folks, because it is going to be a demon of a hangover.