What are different ways to prevent an overpopulation?

Before we go into the solutions, I'd encourage that you take a look at Don't Panic, by Hans Rosling. In it, he addresses many trends regarding population growth, poverty, and energy usage. read more

Similarly, overpopulation is a function of resource usage times the efficiency of resource usage. As such, a relatively small population that travels to space may wipe out the remaining resources of the earth while an even larger population than present may be supportable if certain reductions in resource consumption are adopted. read more

Data from the United States indicate that exposure to comprehensive programs that detail puberty, intercourse, options of abstinence and birth control, and respecting the sexual rights and decisions of individuals, can help prevent unwanted pregnancies and hence reduce birth rates. read more

If you define overpopulation as a stable population of more than 11 billion people on the planet, then perhaps nothing. The most immediate and moral solution is to voluntarily reduce the level of consumption/greenhouse emissions per person for each person in the top billion, maybe two. read more