UN population figures have always been wrong. Europe and Japan are depopulating. Many countries have birth rates under the replacement rate. The largest birth rates occur in Sub-Saharan Africa which sadly will be dealt with by global climate change. We are already moving in that direction. We just need to remove the few remaining obstacles (like the Catholic Church and right wing conservative Christians).
Don't forget to remove the biggest obstacle first, those evil Jews who survived the last socialist attempt at making this a better planet through genocide.
And global climate change won't affect Sub Saharan Africa at all, except perhaps to make it a bit more lush through increased rainfall. The population of Africa already
hugs the equator, where all the heat is, because life loves being warm and wet.