Santa Fe Institute

Cities, scaling, & sustainability Papers

  • A Unified Theory of Urban Living
    2010 vol.467 , 2 page(s) [Link]
  • Growth, Innovation, Scaling, and the Pace of Life in Cities
    Proceedings of the National Academy of Sciences
    2007 vol.104 no.17 , 6 page(s) [Link]
    Abstract: Humanity has just crossed a major landmark in its history with the majority of people now living in cities. Cities have long been known to be society’s predominant engine of innovation and wealth creation, yet they are also its main source of crime, pollution, and disease. The inexorable trend toward urbanization world- wide presents an urgent challenge for developing a predictive, quantitative theory of urban organization and sustainable development. Here we present empirical evidence indicating that the processes relating urbanization to economic development and knowledge creation are very general, being shared by all cities belonging to the same urban system and sustained across different nations and times. 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), whereas those accounting for infrastructure display 0.8 <1 (economies of scale). We predict that the pace of social life in the city increases with population size, in quantitative agreement with data, and we discuss how cities are similar to, and differ from, biological organisms, for which <1. Finally, we explore possible consequences of these scaling relations by deriving growth equations, which quantify the dramatic difference between growth fueled by innovation versus that driven by economies of scale. This difference suggests that, as population grows, major innovation cycles must be generated at a continually accelerating rate to sustain growth and avoid stagnation or collapse.
  • Invention in the City: Increasing Returns to Patenting as a Scaling Function of Metropolitan Size
    Research Policy
    2007 vol.36 no.1 , 14 page(s) [Link]
    Abstract: With urban population increasing dramatically worldwide, cities are playing an increasingly critical role in human societies and the sustainability of the planet. An obstacle to effective policy is the lack of meaningful urban metrics based on a quantitative understanding of cities. Typically, linear per capita indicators are used to characterize and rank cities. However, these implicitly ignore the fundamental role of nonlinear agglomeration integral to the life history of cities. As such, per capita indicators conflate general nonlinear effects, common to all cities, with local dynamics, specific to each city, failing to provide direct measures of the impact of local events and policy. Agglomeration nonlinearities are explicitly manifested by the superlinear power law scaling of most urban socioeconomic indicators with population size, all with similar exponents (*1.15). As a result larger cities are disproportionally the centers of innovation, wealth and crime, all to approximately the same degree. We use these general urban laws to develop new urban metrics that disentangle dynamics at different scales and provide true measures of local urban performance. New rankings of cities and a novel and simpler perspective on urban systems emerge. We find that local urban dynamics display long-term memory, so cities under or outperforming their size expectation maintain such disadvantage for decades. Spatiotemporal correlation analyses reveal a novel functional taxonomy of U.S. metropolitan areas that is generally not organized geographically but based instead on common local economic models, innovation strategies and patterns of crime.
  • The Kind of Problem a City Is
    SFI Working Paper
    2013 vol.13 no.8 , 15 page(s) [Working Paper]
    Abstract: The title of this essay is taken verbatim from the challenge posed by Jane Jacobs in her influential book the Death and Life of Great American Cities (1). My main objective is to answer Jane Jacob’s question with the benefit of over 50 years of research since its publication and especially from the perspective of new insights from the emerging science of cities as complex systems. I show that we have made significant progress over the last decade and that a science of cities, recognizable across the full spectrum of urban disciplines, from physics and biology to social psychology and sociology is starting to emerge. Here, I show that cities are not only complex adaptive systems, a point already clear for several traditions of urbanism, but demonstrate also that they are a particular and unique type of system, a new organizational invention that can combine and amplify the cognitive abilities of humans and generate open-­‐ended socioeconomic development.
  • The Origins of Scaling in Cities
    2013 vol.340 no.6139 , 4 page(s) [Link]
    Abstract: Despite the increasing importance of cities in human societies, our ability to understand them scientifically and manage them in practice has remained limited. The greatest difficulties to any scientific approach to cities have resulted from their many interdependent facets, as social, economic, infrastructural, and spatial complex systems that exist in similar but changing forms over a huge range of scales. Here, I show how all cities may evolve according to a small set of basic principles that operate locally. A theoretical framework was developed to predict the average social, spatial, and infrastructural properties of cities as a set of scaling relations that apply to all urban systems. Confirmation of these predictions was observed for thousands of cities worldwide, from many urban systems at different levels of development. Measures of urban efficiency, capturing the balance between socioeconomic outputs and infrastructural costs, were shown to be independent of city size and might be a useful means to evaluate urban planning strategies.
  • Urban Scaling and Its Deviations: Revealing the Structure of Wealth, Innovation and Crime Across Cities
    PLoS ONE
    2010 vol.5 no.11 , 9 page(s) [Link]
    Abstract: We investigate the relationship between patenting activity and the population size of metropolitan areas in the United States over the last two decades (1980–2001). We find a clear superlinear effect, whereby new patents are granted disproportionately in larger urban centers, thus showing increasing returns in inventing activity with respect to population size. We characterize this relation quantitatively as a power law with an exponent larger than unity. This phenomenon is commensurate with the presence of larger numbers of inventors in larger metropolitan areas, which we find follows a quantitatively similar superlinear relationship to population, while the productivity of individual inventors stays essentially constant across metropolitan areas. We also find that structural measures of the patent co-authorship network although weakly correlated to increasing rates of patenting, are not enough to explain them. Finally, we show that R&D establishments and employment in other creative professions also follow superlinear scaling relations to metropolitan population size, albeit possibly with different exponents.