One of the reasons the Population Law was created in Luke and Jen's world is that the Earth had reached its carrying capacity and there was three years of famine that caused a lot of people to go hungry. Here is a collection of websites and videos that discuss carrying capacity and whether or not this is a real thing that we should be concerned about.

 

One Planet, How Many People? (UNEP)

 

How Many People Can Earth Support? (Live Science)

 

Has Earth Reached Its Carrying Capacity? (How Stuff Works)