I strongly believe we're close to World War III like never before. The US, China and Russia and a League of the Arab nations will play a major role. With nuclear weapons and other sophisticated weapons at hand, it will wipe out more than half the population of human race.
There are more than 10,000 active nuclear war heads in the possession of various nations right now. If all of them are used, then it is quite possible that more than 50% of the human population will be exterminated. The major urban centers will be left without life.