We need a lot more people in the world. Why? Did you ever see a teacher in a classroom at school? She can handle a dozen kids much easier than 2 dozen, and way easier than 3 dozen.
The people who are trying to rule the world need a low population so that they can control the world easier. That's why they are promoting all this nonsense about over-population.
Get out of the city sometime, into the wide open countryside, and see how much more space is there than you would have realized.
With aquaponics and seasteading, we would easily have room for 100 billion on the planet.
I just hope that you are joking. The world definitely can't sustain a population of 7 billion+ and here you are talking about a population of 100 billion. Over-population is the cause of conflicts around the world, be it on the middle-eastern nations such as Syria or in African nations such as Congo. More population means more warfare and chaos.
Why would I be joking? There is easily enough space, materials, capability to produce food and water, and everything we need on earth for 100 billion people.
Perhaps people in Bangladesh are not as happy as they could be. They might be the nation with the least amount of land per person in the world. But even in their dense population, they are living and making it.
Now, it is true that I like the open highways of western America. And if Siberia and Northern Canada were habitable, there is lots of room to make highways to travel. But, the land could handle population density like Bangladesh if the people worked together to make it happen.
If the two things that I mentioned -
Seasteading and aquaponics - were properly applied and used, the whole ocean is there for us to populate on the top of it. And this says nothing about if we grow downward on both sea and land.
On top of this, if the correct form of global warming were made to happen, the Sahara would become a garden, the cold lands of Siberia and Northern Canada would become warm enough to be inhabited, life on the rest of the land could become a beach, the greater warmth could grow lots more agricultural products, there would still be cold climate in the high mountains for people who liked to live in cold, Antarctica might remain cold, but warm enough to live on...
So you see? The possibilities for way more population on earth are essentially far greater than anything that we have now.
One of the greatest needs for mote population is so that we get more intelligent people who can figure out the science to make the kinds of spacecraft that it takes to go to the stars, and start populating the universe.
The ability to go to the stars in far shorter time than rockets could take us there, was developed way back in the 1950s and early 1960s. This is not a dream. This is reality. Check
http://newatlas.com/orion-project-atom-bomb-spaceship/49454/. The only thing we need is a few more intelligent scientists to clean up the few loose ends in the program. We need more population to get these scientists.
Most of the time, the average citizen does not want war or fighting outside of sports competition. It's the leaders who want war. The problem of over-population is a lie. It is brainwashing by the leaders to gain control over everybody for their own ends. War is of their making, not of the general population.