The Guardian recently published this reminder that the real population growth in the world today is happening in Asia and Africa. The article is called, “The 100 million city: is 21st century urbanisation out of control?” Much of the data is from this 2016 paper by Daniel Hoornweg and Kevin Pope, which projected the populations of the world’s biggest cities by 2100.

The standout example is that of Lagos, Nigeria, which went from under 200,000 people in the 1960s to an estimated 20 million people today. Though, I would imagine that the ubiquity of informal settlements makes it difficult to come up with an accurate number.

Still, it is one of the world’s top 10 largest cities and, by 2100, it may be the largest city in the world. The Guardian described the population as young, fertile, and increasingly urban. The median age in Nigeria is 18 and the fertility rate for the content is 4.4 births per woman.

I am mentioning all of this today because I think it grants some perspective. This is an immense city building challenge, not only because of the unprecedented growth rate, but also because it remains largely poor. Lagos, a city, may add more than 2.2x the population of Canada, a country, during the balance of this century.