[Editor's note: This piece was originally featured in "City 2.0: The Habitat of the Future and How to Get There." "The autocatalytic city" has been reprinted with permission from TED Books (TED Books and the Atlantic Cities, 2013). Access more information about the e-book online here.]

Bottom-up growth, driven by citizens, trumps central command.

We are living on an urban planet; our cities are growing at spectacular rates. This growth has created new energy and excitement (cities account for 70 percent of the global economy), and it has highlighted the dysfunctions of cities. Most of our cities, particularly the fastest-growing ones, are messy, confusing places, even for the citizens who call them home. From the massive weeklong traffic jams in Beijing to the crowded favelas of Rio de Janeiro, urban dwellers everywhere can easily rattle off a list of what doesn't work in their communities. The call to action is always the same: "Better planning, better management!"

That call, though, rests on an unquestioned assumption about cities. In this modern age, we think of cities as large institutions or machines. We talk about their failures as failures of management, coordination, governance. We think we could have "better" cities if we could only tune the machine to make it more "efficient." The machine model is implicit in the popular language around "smart cities." The promise is that shiny, smart boxes will figure out how to make our cities tick by smoothing traffic flow, monitoring crime and allocating power through smart grids.

We need to think again. Urban centers are evolving organisms, not engineering problems. Although we are able to control parts of a city -- central business districts, mass-transit systems, water distribution -- we will never hold and understand the whole. Cities are dynamic, complex-adaptive systems composed of millions of relatively free-willed individuals who each day make hundreds of individual decisions that set in motion consequences leading to a million other decisions.

But bottom-up processes -- if we respect and embrace them, rather than try to control them -- create cities that actually work for the people in them.

Picture a city whose streets are narrow and winding. The tangled network branches and turns, some turnoffs leading to even narrower lanes, many leading to dead ends. There are no sidewalks, no front yards and nearly every door is a business -- a store or a workshop. Most likely, there are no maps of this place, and not all of the streets have names. In this part of the city, you do not find a location by asking, "Do you know this house number on this street?" Instead you ask, "Do you know where so-and-so lives?" or "Do you know the shop that sells such-and-such?" And someone will know. There are signs advertising services or jobs, signs upon signs -- for plumbers or painters or music lessons.

Where is this city? If the signs are in Japanese, then you might be in Shimokitazawa or some other district in greater Tokyo. If they are in Hindi, you could be in Dharavi in Mumbai. You could be in the old section of a European capital or in a slum on the edges of a city in South Asia or sub-Saharan Africa, or in the heart of a metropolis in Latin America.  

This city is ubiquitous and is what Matias Echanove and Rahul Srivastava of the Institute of Urbanology call the default mode of urban development. It is what human settlements that grow up without central planning and control look like: seemingly chaotic, labyrinthine and fractal, but thick with social and business networks. Echanove and Srivastava have put together startling images of street scenes in Dharavi (the largest informal settlement in Mumbai) overlaid onto a street in Tokyo or Torino. The texture of the built environment in these disparate places is similar because the dynamics that drive it are similar. The result seems unruly, but it works. The leather workshop uses buckles made by the smithy next door, which also supplies the bagmaker around the bend. The workshops are also stores, and the laborers and clerks are just a few steps from eateries. Many live in or above the shops where they work. This is the urban economy and the urban supply chain at its finest, most dynamic grain.

The default mode of urban development is autocatalytic, driven by the economic logic of proximity and supply and demand. With the exception of water, sewer, electricity and other services that require government, the default mode of urban development provides what is on any planner's checklist for a sustainable and livable city: density, walkability, mixed uses. It builds engines of local development and commerce; the income generated by the shops mostly stays in the neighborhood.

The autocatalytic city also confounds planners and city managers. Authorities have always struggled to control the slums. Officials ignore these areas in policy and planning, or move to demolish them, often with violence. Few cities have taken stock of how much informal settlements contribute to the urban gross domestic product. By some accounts, Dharavi constitutes as much as one-quarter of Mumbai's economy.

The autocatalytic city contains an intelligence, a kind of ingenuity that can never be captured by a top-down system of control. So it is almost poetic that the complexity of the city finds an analogue and an ally in the nonhierarchical complexity of the Internet. In much the same way that the autocatalytic city makes maximum use of physical materials and space, it is also co-opting technology into its fabric.

Community-based groups like Shack/Slum Dwellers International have enlisted citizens to conduct their own censuses and create their own maps, which they publish on open online platforms, thereby expanding our collective knowledge of cities. Map Kibera, for instance, used youth volunteers with handheld GPS units and the wiki OpenStreetMap to create a detailed map of the most famous informal settlement in Nairobi. Until Map Kibera, most government maps showed the area as a forest. The project revealed the network of paths and roads and showed locations of churches, clinics and stores. Residents of Kibera are now using the map as a platform to report uncompleted or badly built government projects, countering official reports and often exposing corruption. Similarly, Transparent Chennai helps informal settlers in the city formerly known as Madras to map their own settlements in relation to (the lack of) government services. These efforts combine local knowledge with technology to engage planners and city leaders.

The use of technology is, like the autocatalytic city, built up incrementally responding directly to needs.

Nowhere is the power of this process more pronounced than in transportation. While services like Uber, Waize, Zimride and Zipcar are disrupting the established regime in the developed world, entrepreneurs in emerging markets are also using information technology and cellphones to radically reinvent transportation, improving services for users and boosting the livelihoods of drivers.

Unlike most cities in the U.S., urban centers in the developing world are transit rich. Informal public transit permeates the urban fabric. Just as the built environment in the autocatalytic city is driven by bottom-up processes, the need to move around in rapidly growing cities with inadequate public transportation has given rise to private transit services (also called informal or paratransit). Each metropolis has its own versions of the same paratransit vehicles: small buses, jitneys, three-wheelers and motorcycles. There are the "trotros" in Lagos; a relative of the "matatus" in Nairobi; and the megataxis in Manila. The "collectivo" minibus of Latin America is similar to the Philippines' "jeepney" and Pakistan's minibus.

In many cities, as much as 80 percent of the population depends on such informal transit. But the meetings of rider and driver have been, until now, up to chance.

Fazilka Ecocabs, named for its small hometown in the state of Punjab, India, has a clever system. It takes requests via call or text message and relays them to the cellphone-equipped "chai wallah" (the guy selling tea on the street) adjacent to the nearest queue of rickshaws. The chai wallah directs a cycle puller to a waiting customer. The customer receives a text message with the expected time of arrival, the fare and the driver's name. This makes the service safer and more predictable for the customer. In return for signing up, Fazilka Ecocabs provides the cycle pullers and their families with free visits to the doctor, educational support for their children and traffic safety training. Ecocabs and similar services are starting to roll out apps to prepare for the influx of smartphones. They could create services that will not only dwarf the customer base of Uber or Zipcar, but also improve the trifecta of environment, economics and equity.

Rather than dreaming up ways to control the autocatalytic city, planners and city leaders should think instead of how to enable it. We must avoid confusing aesthetic order with actual order. We must recognize the native intelligence and resilience of autocatalytic communities and not suffocate them with our push for the logic of efficiency. We all stand to gain, but only if we are prepared to give up control.

Image by szefei via Shutterstock