Dhaka, in bustling Bangladesh, is a megacity growing at an incredible rate. And it’s part of a massive global shift:
The earth’s countryside is emptying out, more quickly all the time. It took about 10,000 years for the human population to become 3 percent urban — a period extending roughly from the dawn of human settlement until 1800. A century later, Earth was still just 14 percent urban. But in 2007, the United Nations announced we’d crossed a monumental threshold. For the first time, more than 50 percent of the world lived in cities rather than rural villages and farms. By 2030, some projections say more than 80 percent of humanity will be urban, with many inhabiting the slum-choked cities of the developing world.
The shift is “a watershed in human history, comparable to the Neolithic or Industrial revolutions,” urban theorist Mike Davis wrote in his book “Planet of Slums.”
In the simplest sense, this transformation has a dual cause: Masses of migrants are abandoning the countryside, and they keep having babies after coming to town. By some accounts, fertility is a larger slice of the pie.
“It’s roughly a 40/60 split,” said Deborah Balk, an urbanization specialist with the CUNY Institute for Demographic Research in New York City. “We have more large concentrations of people than we’ve ever had before. That is new. And those concentrations themselves, they have momentum.”