Monday, 23 January 2012

Cities: regular, large, and supersize

Posted by Dr Max Nathan, SERC and LSE Cities

Yesterday’s Observer ran a great piece on megacities and city growth in China and India. Both countries are urbanising rapidly: China has just become majority-urban, and India’s population is predicted to be 40% urban by 2030. The authors also make great play of two countries’ urbanising trajectories: top-down and massively resourced in China, slower and more organic / chaotic for India.

Despite the rather misleading headline, the piece also correctly points out that megacities will be the exception, not the norm. This is a crucial point for policymakers. Rather than a world of super-size cities, large and regular-size places will be far more common.

Some numbers. The count of megacities (with 10m people or more) is rising – from two in 1950, three in 1975 to 19 in 2007. By 2025, the UN predicts there’ll be 27. But the number of ‘large cities’ – five to 10m people – is already bigger, and growing faster. In 2007 there were 30: the UN suggests there’ll be at least 48 by 2025. More importantly, half the world’s urban population live in much smaller cities, of around 500,000 people. These may be the most common of all. So in fifteen years’ time we’ll see far more Liverpools (around 400,000 people) and Londons (8m people) than Tokyos (26m people).

*

Paradoxically, the very biggest urban settlements are now hard to recognise as cities at all. Across the world cities are merging into mega-regions: notably China’s Pearl River Delta, the US Eastern seaboard, even the Greater South East.

Some of these numbers are difficult to take in. An estimated 120m people live in the Pearl River Delta, the largest urban zone on the planet – China is now planning to merge nine cities in the Delta to create a single sprawl of 42m people. The Tokyo-Nagoya-Osaka-Kyoto-Kobe region may comprise 60m people by 2015, almost the entire population of the UK.

All this may suggest that urbanisation is accelerating. In fact the opposite is true. Globally, cities grew fastest in the 1950s and early 60s: growth rates have been slowing ever since, from 4.1 percent to 2.5 percent today, and a predicted 1.8 percent by 2030. Developing countries are also on the same downward trend.

Urbanisation runs in parallel with economic development, and so as developing countries industrialise, their urban systems tend towards steady state. Of course there is a lot of city by city variation. For example, the UN predicts Dhaka will keep growing – from 15.9m in 2007 to 22.8m in 2025. But Lagos, which has grown from less than half a million people in 1950 to over 13m in 2007, is predicted to reach just 16m in the next fifteen years.

*

Like many researchers, the Observer piece spends some time on the growth of urban slums. Again, the picture is complex. Over the past decade the share of urban slum dwellers has actually fallen from 39 to 32 percent, due to economic growth and policy interventions. But as people are flowing into cities faster than infrastructure can keep up, the absolute number of people in informal settlements is growing, and will keep growing. Ed Glaeser describes slum neighbourhoods as ‘private energy, public failure’: the development challenges of poor public health, chaotic infrastructure and urbanised poverty remain considerable.

*

Finally, we need to factor in the geography of climate change. Many megacities are coastal, and will be threatened by rising sea levels. Many will also be increasingly water-stressed in the years to come.

In his excellent book The New North, Laurence Smith explores the economic rise of the NORCS – cooler, resource-rich regions stretching across Canada, Scandinavia and parts of the US, Russia and China. He predicts new ‘hydrocarbon cities’ appearing across Canada and Russia, and new mega-regions like Cascadia – spanning Portland, Seattle, Vancouver and parts of NorCal.

Megacities are a great symbol of the global urban shift. But our urban future is going to be much richer and more complex than this. The sooner we recognise that, the better we’ll be able to plan for it.

A version of the piece first appeared on the squareglasses blog.

No comments: