What field of scientific study should I go into if I want to decrease the world's population? According to Scott Aaronson, there are open problems in nitrogen fixation that once solved by quantum computers/AI will allow for a much more efficient method of nitrogen fixation which consequently will permit a profound skyrocket in population. There must be something that I could work on to cause a reverse this effect. I am thinking of developing a sterilization pill or a virus that sterilizes anyone it infects.