In 100 years we will be an entirely urban species

Chongqing is a dense and smoky inland city, the heavy-industry, high-rise home to over 30 million people. It is to China what Chicago was to 20th-century America, or Manchester to 19th-century England, and it’s growing at an extraordinary rate. Every day a tide of 1,500 new people washes in to Chongqing. Every day an extra 1.5 million square feet of floor space is constructed for new residents. It’s a vast megalopolis, a megacity of the sort that will soon take over the world.

I met Mr and Mrs Zhang on the day they first arrived in Chongqing from their rural village. It had taken them almost ten years to raise enough money to move and required outrageous sacrifice: a brutal savings regime and years living in a fetid slum far away from their children, who they saw only once a year. On the week I visited them in the sweltering heat of the Sichuan summer, they had pooled together their accumulated cash from years of sweated labour in motorcycle-parts factories, and had paid the full purchase price of 150,000 yuan (£14,000) for a clean and elegant three-bedroom apartment, turning them, legally, into city-dwellers. In the next few months they will bring their parents over from the village, shutting the farm down and ending their family’s millennia-long connection to the fields. The driving force behind their exodus, Mrs Zhang, is a spark plug of a woman with tired eyes but a pitbull’s tenacity, who long ago resolved to save her family from peasant farming at any cost.

The Zhangs are the archetypal people of the 21st century, and we ignore their story at our peril. For the defining force of this century, almost certainly more significant than war, recession and perhaps even climate change, will be the huge and final shift of human populations from rural areas to cities.