I think that we won't. But there will be a one world government. It could be because of a 1984 scenario, but I think by the time we get to the OWG, it won't be us, our human race. The species will have evolved too far to call it 'humanity'.
I've heard it said that by the next couple decades man will have changed into another species. There are significant physical* changes that mark this, but also ideological and intellectual ones as well. I should remind anyone reading this that the difference between two species isn't the ability to breed, but the unwillingness to breed. Outside of fetishists you wouldn't fuck a caveman/woman, would you? Same for a new man human looking back at 1920's humans.
*Physical changes including vastly increased cranial capacity. Since the caesarian section was invented cranium sizes, and IQ have been ballooning. The main limiter on child birth in men is the need for us to exit the womb, the head being the limiting factor. That's why so many women die in childbirth and why are kids are so fucking stupid compared to other animals. Our physical size is also increasing massively, no pun intended, 100 years ago only nobles were average height today, Goliath was like scarcely 6'.... The most important parts of humanity are science and technology, both of which are about to explode in puissance and intimacy with our race. Insert Space Odessy clip here.