The new millennium heralded the start of the age of cities. For the first time in the history of mankind the majority of the world’s population is now living in cities. Whereas in past centuries natural population growth primarily occurred in rural regions, today that growth is mainly registered in cities. In the mid-20th century, 30 per cent of the population lived in the world’s urban centres. Today that share stands at more than 50 per cent, and is continuing to rise. By 2050 it is expected that 80 per cent of the world’s population will live in cities. more - Background: the age of cities