Not sure I see it in those terms. So long as human procreation exceeds the number needed for steady state (around 2.2 for western-style economies, IIRC) then the population seems likely to continue to grow. We ideally need the global human population to decrease, quite markedly, quite quickly. One way would be war. Another would be pandemic, but a better, gentler way, would be for every couple to only have, on average, one child, for a generation or two. We know that overt population control (cf the Chinese one child policy) won't work, because people; so I was just wishing for an external force to bring something similar about.