All who take the sword will perish by the sword" (Matthew 26:52)
It took 1800 AD for the population to become 1 billion - before AD there was a very lengthy BCE btw..
100 billion people supposed to have lived before us in total, assuming most of them died quite young, due to violence and diseases
So if you do the math, there's relative peace in the world cuz of UN agreed Human Rights, which we cannot argue against.. - this is why, there's population explosion now..