In an article for the Washington Post, Max Fisher provides a survey of the United Nations' 90-year population projections. Fisher notes that sub-Sahara Africa will fuel a population explosion that will elevate Africa's total population to over 4 billion by the year 2100.
Asia's population, however, should peak around mid-century at 5.1 billion, but decline to 4.7 billion by the start of the 22nd century. That decline aside, Asia is projected to remain the world's most populous continent in the year 2100.
Europe, North America, and South America are each projected to be well under 1 billion.
The Washington Post article is linked below.
Washington Post Coverage of UN Projections For the Next 90 Years
"If these numbers turn out to be right – they’re just projections and could change significantly under unforeseen circumstances – the world of 2100 will look very different than the world of today, with implications for everyone. It will be a place where today’s dominant, developed economies are increasingly focused on supporting the elderly, where the least developed countries are transformed by population booms and where Africa, for better or worse, is more important than ever."
---Max Fisher, The Washington Post