Geoffrey West, educating us about how cities work.

According to Geoffrey West, distinguished professor at Santa Fe Institute, we need to develop a “science of cities”. West compares contemporary urbanists to the Wright brothers, who are credited with inventing and building the world’s first airplane and making the first human flight. The Wright brothers got their plane to fly, but they didn’t know anything about, for example, aerodynamics. Nowadays, you need science to build a Boeing 747.

The analogy with cities, as West implies, is that we are now urbanizing at an unprecedented speed and that there is no real science that tells us how to do it. Most of our urban planning is based on assumptions, mostly derived from best practices (which are not always time proof). Given the great challenge of urbanization that we are facing (everyday, 1 million people are moving to urban areas), it is remarkable that there isn’t a science that tells us how our cities should grow.

Cities are mammals

As I wrote before, that science is what Geoffrey West has been working for a while. He is conducting research, using methodologies from biology and physics, in order to understand how cities work. Basically, he is trying to find out whether there are quantative predictive laws of life, because, in the end: cities are people.

West and his team already produced some interesting findings, much of them in line with the biology of mammals. There is a certain sub-linear economy of scale, which, for a mammal, means that it needs less energy for every extra cell (the exponent of this is around .75). And that’s all because of how the networks that make an ecosystem function work.



What West does, is essentially trying to understand cities (which are social organizations) in a similar way. The first findings are interesting. There seems to be a same kind of power law that holds for cities. When a city doubles in size, it doesn’t need a doubling of facilities, infrastructure, etc. It would only need about 85% more.

This systemic scaling also appears to hold for socioeconomic quantities. When a city doubles in size, things such as GDP, wages, the number of ‘supercreatives’, patents, etcetera, will be 15 percent more than double.

According to West, bigger cities work better because of the networks. The multiplier effect of networks in bigger cities cause for the pace of life to increase. I’m not sure this is always a good thing (for example, I would rather work in Berlin than in London, because it is less rushy), but it definitely makes cities more efficient for various purposes.

Social metabolical rate

West finished his talk in a way only a physician could: by quantifying why people live together. He explained that the natural daily metabolic rate of a person is around 90 watts (the energy we need to consume to stay alive), but that the social metabolic rate (everything we need to do what we do) is around 11000 watts. Meeting the social metabolic needs of one person can only be done by aggregation: people need to live together in order to meet the needs of every single one of them.

This post is part of a series, reporting from the New Cities Summit in Paris, organized by the New Cities Foundation.

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