"The new report comes just ahead of a demographic milestone, with the world population expected to pass 7 billion in late October. Dr. Zlotnik, director of the United Nations population division said in an interview that the revised numbers were based on new forecasting methods and the latest demographic trends. But she cautioned that any forecast looking 90 years into the future comes with many caveats."
While Africa's population is expected to more than triple from 1 billion currently to 3.6 billion by 2100, the "United States population will rise from today's 311 million to 478 million by 2100." By comparison, "Nigeria, the most populous country in Africa...will rise from today's 162 million to 730 million by 2100."
And what of the world's most populous country?
"China, which has for decades enforced restrictive population policies, could soon enter the ranks of countries with declining populations, peaking at 1.4 billion in the next couple of decades, then falling to 941 million by 2100."