There are only two effective ways to control population growth: 1. Allow the extra population to move to another places and let them make their own living. This is the strategy used by the European nations three hundred years ago. People moved from England to North America so the population density was reduced in England. And those people started a new nation there. In some ways, immigrating to another planet is similar, but will we ever build that space shuttle ?
let’s do a thought experiment: one day the experts in UN announced our mother earth is going to be destroyed by overpopulation within one year, and then the government of every countries start to build the space shuttle together, and those governments plan to hire ten thousand workers to build this shuttle, although the salary is good, nobody is willing to build this shuttle! because since this world is going to be destroyed soon, what’s the use of money ? So in this case, only forced labor, or some form of slavery plus deception and propaganda (like telling the workers that “working means boarding”)can be used to make the workers to built this shuttle. Then after several months the shuttle is built, the shuttle apparently can not hold millions of people so the next question is :who has the right to board this shuttle? the workers said since they built this shuttle and they were promised earlier,so they should have the right to board it, but the upper class said they are the organizers and designers, they are better educated so to preserve human civilization and high culture in another planet, they have to board this shuttle. because almost everyone wants to live so all the people fight to death to board this shuttle and massive disorder broke out on earth…
The first method is not working, so we look at the second method: 2. Self-inflicted population control, China’s family planning program is an example.In China even the chairman of the communist party has only one child, a daughter. He certainly wants two children but he couldn’t.
One-child permission is against the interests of almost every social class and interest groups. To implement that policy, a government can not be a liberal democracy, it has to be a well-functioning autocracy with sophisticated social control mechanism a collective culture. Therefore the liberal democracies like Australia can not copy this even if one day the population there exceed ten billion.
It is true that as people become wealthy and urban that they tend to have less kids, but to become wealthy means to use more natural resources. And many resources in our mother earth is running out. We earthlings may not exist to that day when we are all rich and have less kids.