The ecology of a slum: Part 6, the future’s flows
[Continued from yesterday's Part 5 and the previous Part 1, Part 2, Part 3 and Part 4.]
[Editorial justification for the tour: If we want to improve slums, we have to see them as ecosystems – spontaneous self-generated communities, self-organized, economically rational, economically efficient, adaptive and robust. We may not like the slums (like Dharavi in Mumbai, Kibera in Nairobi, or Sao Paulo's favelas) we may wish them away or wave our hands (or our bulldozers) to disappear them. Yet they will return, resisting our efforts almost as if conscious, unless we see them as organic and dynamic, and come to understand how a slum dies. – Ed.]
I started this multi-part post, using as text Steven Johnson’s excellent book The Ghost Map that chronicled John Snow’s mapping of the 1854
Snow is a hero; so too is Joseph Bazalgette, who retrofitted a modern sewerage system under and through
Eventually, these slums disappeared … but not their buildings
Slums do not simply vanish; nor are they wiped out at a stroke as by an epidemic. Slums evolve – into formality, into the formal city.
Buildings endure; like brick hermit crabs, the buildings’ skeletons may survive multiple generations of use, scoured every score of years, periodically reborn as ‘historic renovations’ or ‘period treasures.’ All that can happen only if the buildings are embraced within the formal city. This takes judicial recognition, which always follows after political recognition, which follows after economic recognition.
Civic acceptance comes in baby steps: painting a street number on a shack, delivering mail to a hovel, enumerating the residents, connecting the toilets to a sewerage system, putting in a legal electric meter. Bit by it, these increments bring the informal into the formal.
Electric hookup box, Ahmedabad Municipal Corporation,
Even as the world is urbanizing at a rate unprecedented in human history, so too are our global cities trying to come to grips with that urbanization.
Somewhere in the world, right about now [2006 – Ed.], a villager is moving her family to a city somewhere, or an urban dweller is giving birth, or a farmer is dying—and with that local isolated act, the global scales will tip decisively. We will enter a new era: a planet whose human population is more than 50% urban. [It's already happened – Ed.]
When John Snow and Henry Whitehead roamed the urban corridors of
People come to cities because, for all their faults, they are richer, livelier, safer, and healthier than rural poverty.
To date, those fears [of cities overrun by population] have proved unfounded. Modern urbanization has thus far offered up more solutions than problems. Cities continue to be tremendous engines of wealth, innovation, and creativity, but in the 150 years that have passed since Snow and Whitehead watched the death carts make their rounds through
We forget that in addition to employment, cities also offer access – access to politics (nearly all revolutions and democracies were born in cities), access to education (the world’s universities were all founded in cities), access to services.
Two-thirds of women living in rural areas receive some kind of prenatal care, but in cities, the number is more than ninety percent. Nearly 80% of births in cities take place in hospitals or other medical institutions, as opposed to 35 % in the countryside.
Cities are places of enterprise.
Delivering fresh eggs back to the neighborhood: Mumbai
You’re much likelier to become rich if you grew up in a city than in the country.
Future millionaires?
We think of cities as making us dumber; actually, cities are hives of innovation.
Because the table condenses down its data into a power-law variable beta, a bit of explanation may help. When the authors speak of an increasing beta, they’re measuring the rate of growth in the quantity as a city gets larger (measured in number of people).
Thus, if a Small city has a patent rate of 1x, when the city becomes Medium sized (growing to 3x its original), it will be producing 35% more patents per capita. It’ll be 35% more competitive. If it makes the leap to a Large city (10x the Small size), its patent rate will be 86% higher. Bigger cities are smarter.
Wages too rise faster than the rate of population. Bigger cities are richer. Move to a city 10x your current one and your earnings will probably rise 32%. (So too will your housing prices!)
We speak of going to the country for our health. Yet on balance we live longer, happier lives in cities:
For those reasons, as you move from rural areas to urban ones, infant mortality rates tend to drop. The vast majority of the world’s most advanced hospitals reside in metropolitan centers.
I know a half-dozen people who would not be alive or healthy today had they not lived in or near
According to the coordinator of the United Nations Global Report on Human Settlements, “Urban areas offer a higher life expectancy and lower absolute poverty and can provide essential serviced more cheaply and on a larger scale than rural areas.” For most of the world’s nations, living in a city now extends your life expectancy instead of shortening it. Thanks to the government interventions of the seventies and eighties, air quality in many cities is as good as it has been since the dawn of industrialization. Pages 231-234
Cities also are, counterintuitively, greener:
Cities are a force for environmental health as well. This may be the most surprising new credo of green politics, which has in the past largely associated itself with a back-to-nature ethos that was explicitly anti-urban in its values. Dense urban environments may do away with nature altogether—there are many vibrantly healthy neighborhoods in Paris or Manhattan that lack even a single tree—but they also perform the crucial service of reducing mankind’s environmental footprint.
Cities sustain greater density for two reasons: they are richer, and being geographically compact, they benefit from square-cube and network effects.
Maybe not welcoming but efficient: Habitat 1967
As we saw in Cities and Scale:
Many diverse properties of cities from patent production and personal income to electrical cable length are shown to be power law functions of population size with scaling exponents, 
, that fall into distinct universality classes.
Quantities reflecting wealth creation and innovation have 
1.2 > 1 (increasing returns),
As cities get bigger, people in them get richer, cleverer, and more creative.
whereas those accounting for infrastructure display 
0.8 < 1 (economies of scale).
As cities get bigger, they need less infrastructure per person.
It’s much easier to hook a peri-urban neighborhood up to a city’s systems than it is to run pipes and wires into the wilderness.
Compare the sewage system of a midsized city like
As the environmental scholar Toby Hemenway argues: “Virtually any service system—electricity, fuel, food—follows the same brutal mathematics of scale. A dispersed population requires more resources to serve it—and to connect it together—than a concentrated one.”
Hemenway likes living close together
From an overall ecosystems perspective, if you’re going to have 10 million human beings trying to share an environment with other life-forms, it’s much better to crowd all 10 million of them into a hundred square miles than it is to spread them out, edge-city style, over a space ten or a hundred times that size. If we’re going to survive as a planet with more than 6 billion people without destroying the complex balance of our natural ecosystems, the best way to do it is to crowd as many of those humans into metropolitan spaces and return the rest of the planet to Mother Nature. Pages 231-234
The ecology of slums and the ecology of cities are linked. Slums are an ecology of concentrated poverty; cities are an ecology of distributed wealth. So in cracking the problem of slums, we are cracking the problem of healthy cities, and hence wealthy city-dwellers.
Buildings survive. Many of those called slums by Snow, Chadwick, and Whitehead still stand in
Where did the slums go? As their economic ecology changed, they melded invisibly into the rest of the city.
This is the world that Snow and Whitehead helped make possible: a planet of cities. Page 234.
If we want a planet of cities, we have to cure a planet of slums. We kill a slum not with demolition but with dollars:
To improve a neighborhood, raise the shelter-cost-paying power of its inhabitants. To do that, raise their ability to earn money, and with it their choices about where to live and what to invest.
How do you eradicate slums? You drive them bankrupt.
The way to win
That’s what Snow and Whitehead sought.
A man who saw the future? Henry Whitehead, 1884
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