CityReads | What Is Urban Science and Why We Need It?
395
Urban science is a novel, integrative approach to cities as complex adaptive systems.
Luís M. A. Bettencourt. 2021. Introduction to Urban Science: Evidence and Theory of Cities as Complex Systems. Cambridge, Massachusetts: The MIT Press.
Source:
https://mitpress.mit.edu/books/introduction-urban-science
Urban environments, created less than ten thousand years ago, have unleashed one of the greatest transformations in earth's history. They have catapulted humans from being a relatively inconspicuous species to becoming the greatest creative force on the planet, the apprentice masters of our natural environment, capable of changing its condition in a seemingly limitless — and often destructive — number of ways. The need to harness this transformative power is ultimately why a scientific understanding of cities is so important. Introduction to Urban Science: Evidence and Theory of Cities as Complex Systems by Luís M. A. Bettencourt of the University of Chicago provides a systematic introduction and explanation of the emerging discipline of urban science.
Why urban science?
We are living through the fastest stage of this global transformation. Over the next few decades, the vast majority of humans still leading a traditional subsistence existence today will likely come to live in urban environments. Although definitions vary, it has become standard to identify 2007 as the year when more than half the world’s population became urban. The next major landmark year will be 2021, when we are estimated to reach peak rural population. After that, each net new human on the planet will be urban! Because of these transformations, the typical daily experience for most people around the world will change and become familiar to most of us already living in urbanized countries. Through this process, we will become more connected to each other and, surprisingly perhaps, to all earth's natural environments.
There are a number of well-known statistical associations between urbanization and human development. The most famous is the relation between national economic income per capita GDP and the percentage of people who live in cities (urbanization). Figure below shows the trajectories of different nations on the plane defined by these two variables. It is striking that out of such a noisy set of trajectories there is a clear average trend.
But it is also true that if you follow any of the national trajectories in detail you will find many exceptions. There are times when urbanization increases without corresponding growth in GDP per capita (urbanization without growth) and vice versa (growth without urbanization).
The figure below compares the human development in the largest cities to their nations. The human development index (HDI) measures broad progress toward improving human capabilities and includes three main components: real income, life expectancy, and education. In almost every case, we see that large cities in each nation display higher levels of human development than their corresponding nations, implying a general tendency for the HDI to increase with city population size. The few exceptions are low-income nations recently torn apart by civil war, such as Liberia and its capital, Monrovia.
These general considerations lead us to some of the great questions of our time, most involving cities and urbanization more or less directly: Why is urbanization now proceeding so relentlessly and globally? How can its consequences be good for most people? When do cities produce fast human development, and when do they fail? Will urbanizing societies become environmentally sustainable quickly enough?
Answering such questions requires new fundamental knowledge that does not exist in any traditional discipline today. Cities are the nexus for all these issues, providing many examples of systemic phenomena that we do not yet understand. We need urban science to answer these questions.
What is urban sciences?
Urban science is a novel, integrative approach to cities as complex adaptive systems. Governing changing cities requires knowledge of their processes as complex systems.
Until recently our understanding of urban processes all around us was very limited and that a much deeper and systematic scientific engagement with cities and urbanization is a necessary precondition for us to fulfill the enormous positive potential of these transformations.
The key is a more fundamental understanding of the processes facilitated and, in many cases, unleashed for the first time by urban life. All great scientific theory relies on the understanding and formalization of fundamental processes of change.
The three main ingredients, specifically interdisciplinary integration and synthesis, a rich and expanding empirical basis and methods across scales, and honoring diverse human experiences create a culture for urban science that holds a special new place among traditional disciplines.
Cities as complex systems
Cities have always been conceptualized — philosophically at least — as complex systems either in their own right or through analogies to organisms, beehives, ecosystems, nervous systems, and other things. However, a couple of seconds' reflection immediately manifests the insufficiency of any of these metaphors. For example, cities are much larger, achieve much higher power densities, and create new information much more quickly than any of these other complex systems. Cities, in fact, are made by connecting all these different complex systems together in specific ways, generating a new "metadynamics" that appears more complex and open-ended than any of its parts.
Describing the complexity of urban processes has been a major goal for the social sciences especially in sociology, anthropology, and economics. In sociology, the idea of "human ecology" developed by researchers at the Chicago School of Urban Sociology, but also by some early urbanists and planners such as Patrick Geddes, became a foundational concept for understanding cities and for developing appropriate interventions and policies.
The clearest idea that cities are complex systems was first articulated in a very practical context in New York City in 1961. Jane Jacobs's main point was that cities are problems in organized complexity because they "present situations in which several dozen quantities are all varying simultaneously and in subtly connected ways." This implies that many factors in cities affect each other and that causality is almost always circular, organized as vicious and virtuous cycles of change.
Ideas about organized complexity have become, in due course, what we call today complex adaptive systems. Cities as complex adaptive systems exhibit to various degrees the following properties: heterogeneity, interconnectivity, scaling, circular causality, and evolution.
First, heterogeneity refers to the fact that large cities are very diverse. There is a positive and a negative side to this. Heterogeneity may refer to types of professions or businesses in a city, to wealth disparities, to race and ethnicity, and other things. It should be clear that all these properties vary immensely among individuals in a city but also across urban space, such as from one neighborhood to another. Is the heterogeneity of cities a "bug" or a "feature"? Does it have a purpose? Should it be sustained or discouraged?
Second, everything in a city is subtly interconnected in networks. For example, issues of economic development or public health are connected to physical places and to urban services, and these in turn are connected to economic budgets at the individual and municipal levels. How may we disentangle some of these issues so we can develop practical solutions?
Third, the character of cities changes with their scale, usually measured by population size. Larger cities within the same nation are usually denser and make more intense use of their infrastructure, with both associated benefits and costs. Larger cities are also more productive economically but also more expensive. Thus, dealing with issues of cities is generally a scale-dependent problem. In particular, larger cities have some advantages and disadvantages in terms of social and spatial freedoms relative to smaller towns, which exactly compensate each other across an urban size hierarchy.
Fourth, virtually all important issues of cities show circular causality. For example, is a city rich because it has good infrastructure or does it have good infrastructure because it is rich? This is obviously an important question: should we try to make a city richer by investing in better infrastructure or wait and build it once we are richer? This circular causality is characteristic of cities as systems in approximate spatial equilibrium.
Finally, people, businesses, and the city itself change over time to adapt and to explore new circumstances. This typically leads to processes of economic growth and development that are gradual (but often fast!) and history dependent: cities evolve.
These properties of cities as complex systems will force us to frame urban science in a way that goes beyond existing theory in any particular discipline, be it sociology, geography, economics, or complex systems. The challenge requires identifying and formalizing essential phenomena at different scales and articulating their consequences in both the "macroscopic" aggregate (entire cities and nations), where these effects are typically first measured, and their "microscopic" origins and influences on people and places.
Urban science deals with diverse interconnected phenomena across different scales and traditional disciplines. Providing an articulation between billions of people living in millions of neighborhoods in thousands of cities worldwide is key, as is identifying phenomena that occur primarily at specific scales but have impact on the system as a whole. For example, economic growth and human development have their origins in people's opportunities and decisions over time, at home and at work, and on their capabilities in neighborhoods, but these outcomes are also facilitated by network effects in cities (scaling), which amplify local decisions into national economic growth processes and other broad aspects of change.
Urban Science does not tell you what to do, but it identifies barriers and opens up pathways to address problems that seem difficult, expensive or slow, in new ways.
Related CityReads
18.CityReads│Urban Design as a Solution to Urban Ills28.CityReads│What Is the Nature of Cities32.CityReads│How An Urban Theorist Sees Urbanization？47.CityReads│Why Are Cities, Nuclear and Genetic Engineering Green?
50.CityReads│Healthy Parks, Healthy Urbanites78.CityReads│Urban Environmental Impacts: Advantages or Penalties?
98.CityReads│What Jane Jacobs Got Right and Wrong about Cities?123.CityReads│How to Escape the Progress Traps?165. CityReads│Scale: Simple Law of organisms, Cities and Companies178.CityReads│Urbanization Without Industrialization in Africa202.CityReads│How Our Modern Urban Life Came to Being?205.CityReads│When Darwin Meets City: How the City Drives Evolution206.CityReads│Lost Cities: 1000 Ways to Die216.CityReads│When the Water Comes226.CityReads│How to Kill Jane Jacobs's City?227.CityReads│Man-Environment Relationships in the 21st China239.CityReads│Let There Be Water: Israel’s Water Solutions247.CityReads│Seeing Trees274.CityReads | 10 Books on City and Public Health
289.CityReads | Urban Labs: From Chicago to China and India292.CityReads | Why Everyone Thinks Cities Can Save the Planet?293.City Reads | Making a Living in Jane Jacobs’s Sidewalk338.CityReads | How Green Became Good?
344.How Five Grand Transitions Have Shaped the Modern World?348.CityReads | How Amateurs Have Changed Urban Theory and Practice?
351.8 Books on Environmental Destruction, Climate Change and City
353.CityReads | Why We Need Romantic Geography?
358.CityReads | Survival of the City375.CityReads | The Yellow River in 3,000 Years
376.CityReads | Invisible Underland
380.CityReads | Small Cities, Big Issues386.CityReads | The Future Is Vast390.CityReads | How Can We Plan for Urban Futures Beyond COVID-19?393.How Quarantine Has Shaped Buildings, Streets, and Cities?
（Click the title or enter our WeChat menu and reply number ）
"CityReads", a subscription account on WeChat,
posts our notes on city reads weekly.
Please follow us by searching "CityReads"