No one knows exactly how growth rates will change in the future, so it is impossible to predict when or at what level the human population will level off. In 2015, the United Nations issued three projections for the world’s population, assuming high, medium, and low growth rates. The highest projection says the Earth’s population will be around 16.6 billion (and still growing) in 2100.
The medium estimate shows the population stabilizing at around 11.2 billion by 2100. The low estimate predicts that the population will peak at just over 8.7 billion in 2050 and then it will decline to about 7.3 billion by 2100.
These projections are only as good as their assumptions. Will birth rates in developing countries continue to decline? If so, by how much, and how fast will it happen? Will birth rates decline by the same amount in all countries? Will more-developed countries be willing and able to provide family planning services even as the rural populations of less-developed countries continue to grow? The answers to these questions will determine the future of Earth’s human population.