The nightmare of the not-too-distant future could be Cairo or Jakarta or any of a dozen other urban monsters that loom just over the demographic horizon. Already Mexico City, Sao Paulo, and Shanghai are among the largest, most congested cities on earth. Over the next two decades, they – and many others – are expected almost to double in size, generating economic and social problems that will far outstrip all previous experience.
Just 30 years ago some 700 million people lived in cities. Today the number stands 1’900 million, and by the end of the century it will top 3’000 million – more than half the world’s estimated population.
The flood of “urbanities” is engulfing not the richest, but the poorest. By the year 2100 an estimated 750 million people will crowd into 60 cities of five million or more – three-quarters of them in the developing world. Only a single First World city – metropolitan Tokyo, which will have 24 million people – is expected to be among the global top five; London, ranked second in 1950 with then ten million inhabitants, will not even make 2000’s top 25.
What confronts and confounds urban planners is the enormity of these trends. There have never been cities over 30 million people, let alone ones dependant on roads, sewer and water supplies barely adequate for urban areas a tenth that size.