Demographers say more than 80 percent of the global population will live in Asia and Africa by 2100:

The chart above comes from GeoHive's analysis of various international data sets. It shows how the world's human population shifted over the past few centuries and is projected to do so over the next century.

Asia, as the world's largest continent, was home to 63 percent of the human population in 1750, but is only expected to contain 45 percent of the population in 2100. Europe, once the second most populous continent, is now fourth, and it's expected to actually lose 50 million people by 2100. And Africa's population is expected to soar from 811 million in 2000 to nearly 3.6 billion, or 35 percent of the global population, by 2100.

By 2100, GeoHive's analysis estimates the world population will grow to more than 10 billion — a long way from just 791 million in 1750.

It's worth taking the projections with some skepticism. Just like people in the 1600s had a difficult time predicting the population boom caused by the Industrial Revolution, humans today have a hard time seeing what's going to cause the population to grow or decline in the coming decades. Runaway global warming or nuclear war, for instance, could significantly hinder humanity after 2050. Or maybe there will be some sort of development in genetically modified foods or nuclear fusion that will make much more human life sustainable. It's hard to say.