By contrast, several countries in Africa and the Middle East are set to double in a quarter century. For instance, Kinshasa, in the DRC, is forecast to be among the most populous cities worldwide by 2080 given rapid population growth.

This graphic, via Visual Capitalist's Dorothy Neufeld, shows the fastest-growing populations in the world, based on data from the United Nations.

Years for the Fastest Growing Populations to Double in Size

Below, we show countries with the fastest annual doubling rates at current projections: