Humanity is about to undertake the greatest change of habitat in its entire history. Authoritative international reports to be published over the next months will show that, for the first time, we will soon be a predominantly urban species, with more people living in towns and cities than in the countryside.
Official United Nations figures show that the world's urban population has more than quadrupled over the past 50 years. Almost half of us inhabit towns and cities: within a quarter of a century 60 per cent of us will do so.
London, some 200 years ago, became the first city since ancient Rome to reach a million inhabitants: now, there are more than 200 such cities. About 20 of theseare "megacities" exceeding 10 million, and one, Tokyo, has become a "metacity", with more than 20 million. Reports by Washington's Worldwatch Institute, published next month, and by the UN Population Fund, due in the summer, will describe the imminent transition and grapple with how to cope with the rapidly swelling cities.
The task is all the more difficult and urgent as 95 per cent of the increase is in developing countries, partly through births, but also through migration from the impoverished countryside to swelling slums that are home to a billion people.