Cities Have Lives of Their Own

Animations of the growth of cities over time. We've shown how animation is being used to entertain, to educate, to study biology, and to advance space travel. Next up is a project that uses animation to model urban dynamics.

Students at the New York University have been studying urban sprawl and compiling data on how cities spread. You may never have thought about it much - cities just get bigger - but there actually is a lot of theory about how and why cities develop.

These animations were created by the NYU Stern School of Business Urbanization Project. They were created using created using information from The Atlas of Urban Expansion. I bet you didn't even know there was an Atlas of Urban Expansion! Well, neither did I, but there is.

The colors in the animations have specific meanings. The expanding colors on the maps represent the expansion of 'urban land,' or land developed for residential, commercial and public use. The white space represents rural areas, forests and pastures. Naturally, the colors get bigger and the white space recedes with time, as the cities all - without exception - get bigger with time.

Paris, France

There are several reasons why this is an important topic. Many cities around the world are going to grow, and they will not just grow a little bit - they will grow like mushrooms, taking over surrounding plains and valleys. Much of that growth will take place in "emerging markets" as they say.

A few simple facts:

• The world’s urban population is expected to increase from 3.5 billion in 2010 to 6.2 billion in 2050, and almost all of this growth is expected to take place in less-developed countries.
• Cities in developed countries will add only 160 million people to their populations during this period, while Cities in developing countries will need to absorb 15 times that number, or close to 2.6 billion people, thereby doubling their total urban population of 2.6 billion in 2010.
• Given the expected decline in urban densities, these cities are likely to more than triple their developed land areas by 2050.

São Paulo

Brandon Fuller, the deputy director at the Urbanization Project, has described the maps as 'a plea for some long-term planning.'

'When you tell a policymaker that we need to start getting ready for five-fold, six-fold, seven-fold expansion in a city, they're often in disbelief. But when you can actually see how dramatically [cities grow] over time, it becomes much more real.'

According to the Atlas of Urban Expansion, in 2010 more than half of the world’s total population lived in cities, and this share is expected to increase to 70 percent or more by 2050. Major cities in the developing world will triple in size. That's a lot of growth. I mean, if you were going to triple in size, you'd probably want to know. Planning for that in advance will avoid a lot of problems - securing water supplies, developing transportation routes, planning communities in scenic spots - which is where the NYU project will become useful. One only has to see pictures of major cities in emerging markets that were not planned out (and which shall remain nameless) to know that you don't want to go down that path if you don't have to.

Chicago

Project participant Patrick Lamson-Hall notes:

'Particularly striking is the growth in the latter half of the 20th century, in which many cities increased their built-up area by more than 10 times. This is in keeping with the theory of falling density, which holds that as cities have grown bigger and the world has urbanized, densities have been steadily falling. As a result, cities require more urban land per person, meaning total growth in the city area is much greater than population growth.'

This is just a small taste of the entire project of 60 projected cities, which will be shown at the World Urban Forum 7, in Medellin, Colombia.

2020