With world's urbanized population now at 50 percent, urban living seems set to be the global norm -- though its unclear if many cities can cope with the challenge.
The leap to 50 percent of the world's population living in cities (from 13 percent in 1900) "owes something to science and technology: improvements in medicine, coupled with new knowledge about ways to avoid disease, have enabled more and more people to live together without succumbing as once they did to diarrhoea, tuberculosis, cholera and other pestilences."
"The same developments, however, have similarly lengthened lives in the countryside, leading to a huge increase in rural population. Human ingenuity has not matched this increase with commensurate growth in rural prosperity. As a result, ever more villagers have been upping sticks to seek a better life in the city."
"The sheer scale and speed of the current urban expansion make it unlike any of the big changes that have punctuated urban history. It mostly consists of poor people migrating in unprecedented numbers, and then producing babies on a similarly unprecedented scale."
"The United Nations forecasts that today's urban population of 3.2 billion will rise to nearly 5 billion by 2030, when three out of five people will live in cities."
"Within ten years the world will have nearly 500 cities of more than 1m people. Most of the newcomers will be absorbed in a metropolis of up to 5m people. But some will live in a megacity, defined as home to 10m or more inhabitants. In 1950 only New York and Tokyo could claim to be as big, but by 2020, says the UN, nine cities-Delhi, Dhaka, Jakarta, Lagos, Mexico City, Mumbai, New York, São Paulo and Tokyo-will have more than 20m inhabitants. Greater Tokyo already has 35m, more than the entire population of Canada."
Thanks to Peter Gordon