The biosphere of planet Earth is undergoing it's sixth extinction event, this being a time when biodiversity decreases to such a level that the climax ecosystem dynamics of stability are no longer in equilibrium. Humans becoming extinct altogether, unless through an antibiotic resistant, genetically modified superbug type scenario, I find unlikely, but then you don't need to travel very far back in time to find a time when other closely related Hominids went extinct (Neanderthals etc.).

Also, there has always been a war going on somewhere for at least the last 2000 years. And furthermore, we are entering a new astrological age as the solar system orbits the galactic core. Get with the program!