THE tide of people pouring into megacities has turned. Against expectations, more people are now leaving many of the world鈥檚 largest urban areas than are moving in.
Estimates made during the past two decades suggested that most megacities would continue to swell at an alarming rate. Back in 1984, the population of S茫o Paulo was expected to hit 24 million by 2000. But today, fewer than 18 million live there. Mexico City was to jump from 16 million to 26 million over the same period. But the city has grown by only 2 million, according to last year鈥檚 census, largely because of high birth rates. The situation is similar in Calcutta and Buenos Aires. More people are still quitting than arriving.
The figures contradict the popular belief 鈥� repeated at last month鈥檚 World Summit in Johannesburg by Anna Kajumulo, head of the UN鈥檚 cities programme 鈥� that half the world鈥檚 population already live in urban areas. That鈥檚 not now expected to happen until 2007 at the earliest.
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鈥淐ensuses held in 2000 and 2001 show that the world is less urbanised and less dominated by large cities than had been predicted,鈥� says David Satterthwaite of the London-based International Institute for Environment and Development. Satterthwaite published a new analysis of UN census statistics this week.
Only one of the world鈥檚 largest cities, Tokyo, has grown bigger than expected, largely because the city鈥檚 boundaries have been extended to include scores of smaller cities in the surrounding region. Shanghai, Beijing and Seoul all posted smaller populations than in 1990.
Satterthwaite says that shrinking urban populations are the result of an economic downturn in developing countries and the sheer unpleasantness of giant cities. 鈥淟ife is often better outside the megacities,鈥� he says. Gridlock, pollution and poor city services are driving away both industry and people. 鈥淭he huge car manufacturing plants of Brazil are all leaving S茫o Paulo, for instance,鈥� he says.
The downsizing looks set to continue. Estimates for the growth of up-and-coming megacities like Lagos, Nigeria, have been slashed.
Judging whether the cooling off in growth of the megacities is good or bad news isn鈥檛 easy. While megacities are renowned for churning out pollution, they often generate a lot of money. But continued growth in megacities might simply reflect a lack of jobs elsewhere. At least with accurate figures, city planners, who deal with everything from new roads to sanitation, will have a better idea of their city鈥檚 future needs.
