City populations are growing and rural populations are shrinking. By 2030, 60% of the world’s people will live in cities; by 2050, the figure is likely to be 70%.
Nearly a quarter of the world’s population in 2030 will live in a city with more than one million people. Nine of the 10 most populous cities in 2030 will be in Asia and Africa (the exception is Mexico City); they will all have more than 23 million people.
Not all cities are created equal, however. Large countries like China, India, and the U.S. have urban populations spread across multiple geographic areas.
By contrast, in 28 countries, there’s one big metro center where as much as 40% of the urban population lives. Several are in areas prone to political instability and conflict, including Kabul, Afghanistan and Mogadishu, Somalia. Others are highly vulnerable to natural disasters and climate change.
Before Hurricane Maria, San Juan, Puerto Rico was home to 72% of the island’s residents. According to a data booklet on cities by the U.N., 56% of global cities with populations of 300,000 or more are at risk of natural disasters. Collectively, they are home to more than 1.4 billion people.