Ludwig Siegele on Planet of Cities

Mr Angel does not hide his agenda: he wants to demonstrate that the movement of people into cities cannot be stopped; trying to slow down urbanisation and even stop it will produce all kinds of unpleasant side effects, he argues, not least driving up housing prices—which hurts the poor the most. Seoul, which established a protected greenbelt in 1971, is a case in point. By 1990, the average household in South Korea’s capital had to pay ten times its entire income to purchase a basic housing unit.Rather than copying such efforts to limit urban expansion, as some environmentalists advocate, rapidly growing cities in developing countries should take a page from New York and Barcelona, says Mr Angel. In the 19th century both cities decided to prepare themselves for rapid growth. In 1811 New York’s city council approved a plan which allowed all of Manhattan to be built up and included the island’s now famous street grid. In 1859 Barcelona followed suit with a similar concept to expand the city nine-fold.Cities in developing countries must be equally ambitious if they want to be able to control the masses of people coming their way, says Mr Angel. They should plan for an arterial grid with roads no more than one kilometre apart and that covers an area big enough to accommodate newcomers for the next 20 to 30 years. And instead of surrounding the city with a greenbelt, they should protect sufficient open space within the city limits.