The curse of urban sprawl: how cities grow, and why this has to change

The curse of urban sprawl: how cities grow, and why this has to change
Shanghai in China, one of three countries where 37% of all future urban growth is expected to take place / © Philipus/Alamy

The total area covered by the world’s cities is set to triple in the next 40 years – eating up farmland and threatening the planet’s sustainability. Ahead of the latest Urban Age conference, Mark Swilling says it is time to stop the sprawl

I have just spent two days in Barcelona, one of the most densely populated urban settlements in the world. There are 103 road intersections per sq km – high compared to Brasilia’s 41 or Shanghai’s Pudong area, which has only 17. Yet despite these high densities, residents of Barcelona will tell you how profoundly liveable their city is.

Visitors are charmed by the pedestrianised streets that thread their way through a maze of buildings constructed over the centuries – between four and seven storeys high, on narrow streets leading to piazzas where people sit at cafe tables or under shady trees. Many residents walk or cycle to work, and public transport functions very well.

For the first time in human history, most of us live in urban settlements – from megacities of 10-20 million, of which there were 28 in 2014, to medium-sized cities of 1-5 million (417 in 2014), and smaller settlements (525 of between 500,000 and one million people in 2014). Looking ahead, the biggest growth will occur not in megacities but these small- and medium-sized cities.

Metropolises expand and contract. It is estimated that 40% of Europe’s cities are shrinking (though this is a trend that migration might help to reverse). Even in Africa, there are some countries where the percentage of the total population living in cities has declined at various times over the past two decades.

Overall, however, our current urban population of around 3.9 billion is expected to grow to around 6.34 billion by 2050, out of a total global population of at least 9.5 billion. If we continue to design and build as if the planet can provide unlimited resources, then this near-doubling of the urban population will mean a doubling of the natural resources required to build and operate our cities – which is not sustainable. […]