A Mega-Urban World?
Luis Bettencourt is a professor of complex systems at the Santa Fe Institute where he works extensively on cities and urbanisation. As a theoretical physicist he’s interested in the potential of data to inform the way our future megacities might be run.
Words Luis Bettencourt
Illustration James Round
“Provided that some groups on Earth continue either muddling or revolutionizing themselves into periods of economic development, we can be absolutely sure of a few things about future cities. The cities will not be smaller, simpler or more specialized as cities of today. Rather, they will be more intricate, comprehensive, diversified and larger than today’s and will have even more complicated jumbles of old and new things as ours do.”
Jane Jacobs, The Economy of Cities, 1969.
When the passage above was written, almost 50 years ago, Jane Jacobs’ muse, New York City, was one of only two megacities in the world. Its population was about 11.5 million, similar at the time to that of Tokyo. The population of the New York metropolitan Area has since almost doubled, while that of Tokyo now approaches 40 million.
Megacities are the most spectacular expressions of urban growth, and today there are almost 30. If developing cities such as Delhi, Shanghai, Jakarta or Lagos can sustain their annual population growth rates for another few decades, they will surpass Tokyo and set new records for city sizes over 50 million people.
These trends complete a historical process by which the majority of humans have become city dwellers. Through urbanisation, starting modestly about 10,000 years ago, humans have transformed themselves from typical biological creatures living on the land at densities less than 1 person/km2, to a species that is massively social: the population density of parts of Hong Kong exceeded 1m/km2 in the 1990s, likely a world record.
Those were not the happiest of places or the happiest of times. But this number; a shift of about a million in the intensity of our sociality, tells an interesting story about the string of innovations that made it possible, and reveals much about the multidimensional and complex nature of life in megacities.
Large cities have always boggled the mind of even the smartest humans. From classical times, Plato, ever enamoured with mathematical ideals, put perfect population size of a city at 5,040. Aristotle, always more pragmatic, extolled the benefits of people’s ability to know each other for civic governance. He tied population size to function, as the “city exists for the sake of living well.” Aristotle’s reasoning could have bypassed many of the flaws of early urban planning, which tried to limit urban growth through green belts, resident’s permits and other ill-fated and clumsy policy devices.
The point about cities is that they are adaptive complex systems, characterised by an evolving, dynamic balance of many different and seemingly disparate forces. The balance of these forces can shift as technologies advance, economies develop and civic and political institutions adapt. As the problems of earlier cities were overcome — such as slow transportation and dismal public health — cities were able to shift the balance between their costs and benefits and become much, much larger. Thus were megacities born.
How then are we to understand and measure the pull of cities and explain their limits? On the one hand, the costs of living in large cities are all too apparent. Large city life is a constant struggle for time, space and money for all but the richest. Higher rates of crime, pollution, noise and infectious diseases tend to compound these costs.
But all these nefarious quantities are the result of the need to sustain high rates of socioeconomic interactions in space and time. These drive our need for movement, for nearby spaces to live and work, and for their maintenance, which in turn requires energy and creates waste. It is the result of these social interactions — primarily between strangers — that is the true essence of the city.
Large cities are mesmerising as showcases for new businesses, art forms, entertainment and emerging technologies. New and more specialised businesses, many of them unique and valuable, are only possible as they serve larger and more heterogeneous populations. Interactions between strangers, within or across organisations, force each one of us into interdependent professional and personal niches, creating a deeper division of labor and more knowledge in our societies in general. The diversity of large cities is real but it is not accidental: it is the result of myriad adaptations by individuals and organisations to t in a rugged landscape of other interconnected urban strugglers.
This anonymous and almost invisible web between people is a unique product of urban societies, and at its densest it exists only in the largest cities. In developed places with good data, these effects become clear and are known as agglomeration effects (in urban economics and geography) or scaling effects (in complex systems and engineering). It is well known, for example, that the size of the economy of a city — measured by GDP, profits or wages — increases more than proportionally to population, expanding by about 10 to 20 percent per capita with each doubling of population size.
The explanation for this crucial property of cities is that they are not so much a concentration of people in space, but a concentration of connections of all types: economic, social, civic, personal and more. This concentration is also temporal, as each person can experience more exchanges in the same physical amount of time. This makes cities a sort of social reactor — analogous in some ways to a star — where higher densities create higher rates of interactions per unit of time, resulting in outputs that are more complex and valuable per person.
The daily costs of living in large cities rise with their benefits because they share the same origin, creating cities of many different sizes. However, new knowledge and socioeconomic structures result in larger urban systems, changing life irrevocably by affording each person the fruits of the labor and knowledge of millions.
If all cities hang in the balance between their costs and benefits, this balance is much more delicate and exacting in megacities. The algebra carried out by their residents involves balancing the massively positive to the enormously negative. Such a situation is prone to accidents, missteps and instabilities.
“If all cities hang in the balance between their costs and benefits, this balance is much more delicate and exacting in megacities.”
Most of the world’s megacities have clear and present problems that are likely to curb their growth and detract from their socioeconomic potential. Problems of air quality, pollution and noise require that solutions for energy, water and transportation improve on current models and do not follow in the footsteps of the largest cities in China or India today. Technologies already exist to decarbonise the energy supply, electrify and speed up transportation and better manage resources through sharing and public service models. It is not unimaginable that pushing on these ideas could easily sustain green megacities larger than contemporary Tokyo.
Other problems of megacities loom larger. Many of the inhabitants of the world’s fastest growing cities live in slums and lack the social and civic integration, or the urban services, that would allow them to be more creative and entrepreneurial agents in their societies. Much of their daily labour is spent playing the role of infrastructure. They pay, with their time and effort, for all but the most basic services that allow them to survive another day.
The gradual but steady integration of all people into a dynamic of human development and economic growth is natural in cities, and has been one of the great miracles of developed urban societies. This dynamic must now play out on a massively larger scale, faster and more effectively, to billions of people worldwide. This process is underway but will require a finer knowledge of the complex nature of life in cities, and of the many dimensions that practical solutions to such problems must take to be effective.
The key to understanding cities is to approach them as massive socioeconomic processes for collective learning and adaptation by people. In cities and through urbanisation, a vast web of interdependence of work and knowledge is spun that can allow each one of us to pursue our personal interests productively, and to live better through our collective achievements, big and small. All this will not change, but a planet with many megacities will take this dynamic to a new level — we should look forward to faster, more eventful lives with many surprises.
“At the social level, the challenge of future cities will be to create economic systems that allow anyone to participate and thrive.”
What can probably be guessed about the nature of future megacities is that their informational nature will become ever more apparent and many of their parameters may change, perhaps radically.
The first set of transformations is non-negotiable. It deals with the nature of ‘urban metabolism’ — that is with managing the production and flows of energy, food and other resources that sustain cities, and with associated infrastructure systems. Present urban infrastructure is massive in scale and requires epic investments, causing slow change that too often lags behind social and economic developments; think of water and sanitation pipes in any large city. Larger cities of the future, to be sustainable, will have to close the loop on many forms of resource use: water, trash, and other materials. We already do this now over planetary (CO2) and regional scales (water, trash), with many adverse consequences to human and natural environments.
Can all this — including energy generation — be done more locally, on smaller scales and in more integrated ways? This would shrink a lot of the city’s infrastructural footprint, increasing the ability of urban material substrates to quickly adapt to demographic and economic change in expanding or shrinking cities.
The second set of issues is likely to deal with a compression of urban activities, not just in space but also in time. Cities have always had ‘sharing economies’, but new information technologies that facilitate contracts and coordination may make the co-use of housing, transportation and consumer services on-demand much more pervasive. This would not be some 21st century version of socialism, but rather how economic markets are actually supposed to work, as informational devices. Money, in this respect, is just a signal. Other signals will then find it easier to emerge.
At the social level, the challenge of future cities will be to create economic systems that allow anyone to participate and thrive. As we know all too well, this is the most unknowable and most difficult of all challenges: what will happen to work and employment as technology takes over all routine jobs and services — including food and energy production, transportation, household management and mass retail? The answer is likely to require work that is more heterogeneous, has more embedded knowledge and is more changeable than is the norm today.
Next time you have a delicious meal in a great city, hear music on the streets that touches you, or enjoy an extraordinary new technology think that you may be having a taste of the future and try to imagine a world where value is all about these things — a mega urban world.”
This is article is from Weapons of Reason’s second issue: Megacities.
Weapons of Reason is a publishing project to understand and articulate the global challenges shaping our world by Human After All design agency.
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