Affordable Housing Institute : US

[Continued from Part 1 and Part 2.]

 

In the preceding two posts, we’ve examined and explained the thesis of a new PNAS paper, Growth, innovation, scaling, and the pace of life in cities. 

 

The authors clearly understand the value of solving the problem they have chosen to tackle:

 

These unfolding complex demographic and social trends make it clear that the quantitative understanding of human social organization and dynamics in cities is a major piece of the puzzle toward navigating successfully a transition to sustainability.  7301.

 

To get to their conclusions, the authors shook small mountains of urban statistics, then interpolated growth scalars, yielding conclusions that they boil down into a handy small table:

 

 

Or, using the authors’ trio of distinctions, we find:

 

·         Hardware associated with the city — roads, wires, buildings — show scale economies.  It’s easier to wire the guy next door (or next floor) than down the road.

·         Personal matters are directly correlated.  We use the same amount of space, have the same job rate, consume about the same water and power regardless of city size.

·         Software; social interactions.  Because they are intangible, they are not bounded by physics, and because they are network-driven, they benefit from expansion.

 

This last — the software element — has no obvious parallel in biology:

 

[Superlinear scaling reflects] unique social characteristics with no equivalent in biology and [is] the quantitative expression that knowledge spillovers drive growth, that such spillovers in turn drive upon agglomeration, and that larger cities are associated with higher levels of productivity.  … Costs, such as housing, similarly scale superlinearly, approximately mirroring increases in average wealth.  7303.

 

Or, as Sherlock Holmes put it, in Moriarty and Milverton:

 

“The change from greenfield to brownfield — from farms to homes — represents the tangible demonstration of the development equation in operation.  The way I remember it is,” Holmes finished, “is that the most profitable crop one can grow on any piece of property is people: residential property.”

 

“In the same way,” he added with a mischievous twinkle, “criminals go straight when it becomes more profitable to do so, and in point of fact the organizational and financial management skills required to be a successful underground emperor are not so dissimilar from those required to be a successful property developer.”

 

Unfortunately, Watson, bigger cities = smarter criminals

 

Perhaps the only biological analogue to the intellectual or intangible networking effects of cities is the brain’s synapses.  Greater intelligence scales superlinearly, because of network effects.

 

Humans have the highest ratio of brain mass to body mass.

 

As brains grow larger, they develop specializations.  So too with cities:

 

An important result of urbanization is also an increased division of labor and the growth of occupations geared toward innovation and wealth creation.  7301.

 

Bigger brains also mean more mental energy consumption.  Even though our brains represent only about 2% of our body mass, they consume about 25% of our metabolism.

 

Something similar seems to occur in cities:

 

For processes driven by innovation and wealth creation … the pace of urban life is predicted to increase with [city] size.  …  Quantitative confirmation is provided by urban crime rates, rates of spread of infectious diseases such as AIDS, and even pedestrian walking speeds, which when plotted logarithmically, exhibit power law scaling … consistent with our prediction.  7303. 

 

The authors illustrate this, in what might be called a decisive demonstration, with a figure:

 

The caption reads: “The pace of urban life increases with city size in contrast to the pace of biological life, which decreases with organism size.  (a) Scaling of walking speed vs. population for cities around the world.  (b) Heart rate vs. the size (mass) of organisms.”

 

[The speed table is log-log on both axes.]

 

You’re not imagining a frenetic pace of urban life: it’s real.  People speed up as they move to bigger cities. 

 

Scaling relations predict many of the characteristics that a city is expected to assume, on average, as it gains or loses population.  The realization that most urban indicators scale with city size non-trivially, implying increases per capita in crime and innovation rates, and decreases on the demand for certain infrastructure, is essential to set realistic targets for local policy. 

 

What they’re offering — maybe — is a means of predicting how rapidly cities will need to scale up their infrastructure both physical (highways, power grids) and sociological (police, hospitals, clinics).  This matters enormously in a world where the urban population of developing countries is expected to more than double by 2030.  Even more than we have to get the physical cities right, we have to get their institutions right. 

 

New indices of urban rank according to deviations from predictions of scaling laws also provide more accurate measures of the successes and failures of local factors (including policy) in shaping specific cities.  7306. 

 

Translation: If your city’s showing unusually bad negative indicators for its rate of growth, you had better change its governance.

 

Let’s finish with quotes from two wise men, first Rakesh Mohan, deputy governor of the Reserve Bank of India:

 

With increasing free trade in services, the price of traded products has almost stabilized across the world.  Goods now have very similar prices everywhere; therefore, no city has any advantage over any other in traded goods.  Comparative advantage of nations will increasingly lie in the relative efficiency of their cities.

 

I’m beginning to think that the twenty-first will be the century of cities, where the two preceding centuries were of nations.  Not that nations will be irrelevant — rather, increasingly a nation will be defined by its large cities, and the cities will both collaborate and compete with each other, attracting people and jobs and ideas, competing for talent and networking ideas. 

 

We will give the last word to 1928’s J. B. S. Haldane:

 

Born in 1892, died 1964

 

And just as there is a best size for every animal, so the same is true for every human institution. In the Greek type of democracy all the citizens could listen to a series of orators and vote directly on questions of legislation. Hence their philosophers held that a small city was the largest possible democratic state. The English invention of representative government made a democratic nation possible, and the possibility was first realized in the United States, and later elsewhere. With the development of broadcasting it has once more become possible for every citizen to listen to the political views of representative orators, and the future may perhaps see the return of the national state to the Greek form of democracy.

 

Unfortunately for Haldane and the world, the first politician who truly grasped the power of media was Hitler.  Fortunately for the world, the second was Churchill, and the third was Gandhi.

 

Even the referendum has been made possible only by the institution of daily newspapers.  

 

Goodness knows what he’d think of blogs.

 

To the biologist the problem of socialism appears largely as a problem of size. The extreme socialists desire to run every nation as a single business concern. I do not suppose that Henry Ford would find much difficulty in running Andorra or Luxembourg on a socialistic basis. He has already more men on his pay-roll than their population. It is conceivable that a syndicate of Fords, if we could find them, would make Belgium Ltd or Denmark Inc. pay their way. But while nationalization of certain industries is an obvious possibility in the largest of states, I find it no easier to picture a completely socialized British Empire or United States than an elephant turning somersaults or a hippopotamus jumping a hedge.

 

Here’s to the future, and what it may hold!

 

[Hat tip: Melanie Walker]

 

 

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