We largely have gotten our act together on family planning, which is why birth rates are below replacement everywhere but sub-Saharan Africa, and dripping there too. Only reason population is still increasing is a combination of lag (it takes the smaller year groups now growing up in India and China to become adults before those countries will tip into population decline (excluding immigration), and waiting for the decline in Africa to hit replacement as well.

UN projections indicate somewhere around the end of the century for a net reduction in people, but long before that we'll see developed countries starting to compete agressively for immigrants, combined with campaigns to push fertility up to try for a soft landing.