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A unified theory of urban living



It is time for a science of how city growth affects society and environment, say Luis Bettencourt and Geoffrey West.
t the start of the twenty-first century,
cities emerged as the source of the
greatest challenges that the planet
has faced since humans became social.
Although they have proven to be human-
ity’s engines of creativity, wealth creation
and economic growth, cities have also been
the source of much pollution and disease.
Rapid urbanization and accelerating socio-
economic development have generated
global problems from climate change and
its environmental impacts to incipient
crises in food, energy and water availabil-
ity, public health, financial markets and the
global economy1,2.
Urbanization is a relatively new global
issue. As recently as 1950, only 30% of the
world’s population was urbanized. Today,
more than half live in urban centres. The
developed world is now about 80% urban
and this is expected to be true for the entire
planet by around 2050, with some 2 billion
people moving to cities, especially in China,
India, southeast Asia and Africa2.
Cities are complex systems whose infra-
structural, economic and social components
are strongly interrelated and therefore dif-
ficult to understand in isolation3. The many
problems associated with urban growth and
global sustainability, however, are typically
treated as independent issues. This frequently
results in ineffective policy and often leads to
unfortunate and sometimes disastrous unin-
tended consequences. Policies meant to con-
trol population movements and the spread of
slums in megacities, or to reverse urban decay,
have largely proven ineffective or counterpro-
ductive, despite huge expenditure.
In New York City in the 1970s, for example,
a strategy of ‘planned shrinkageintentionally
removed essential services from some urban
areas — notably the Bronx — to prompt peo-
ple to move away and allow for redevelopment.
Instead, this strategy led to increases in crime
and general socio-economic degradation.
In North America in the 1950s to 1970s (and
earlier in Europe), policies of urban renewal
intended to reduce high urban densities,
by razing poorer old neighbourhoods and
creating infrastructure, actually ended up
encouraging urban sprawl
. Similar debates
continue to play out in rapidly develop-
ing cities around the world today, from
Beijing to Rio de Janeiro in Brazil, often lead-
ing to similar mistakes.
But cities supply solutions as well as
problems, as they are the world’s centres of
creativity, power and wealth. So the need is
urgent for an integrated, quantitative, pre-
dictive, science-based understanding of the
dynamics, growth and organization of cit-
ies. To combat the multiple threats facing
humanity, a ‘grand unified theory of sus-
tainability’ with cities and urbanization at its
core must be developed. Such an ambitious
programme requires major international
commitment and dedicated transdiscipli-
nary collaboration across science, economics
and technology, including business leaders
and practitioners, such as planners and
designers. Developing a predictive frame-
work applicable to cities around the world
is a daunting task, given their extraordi-
nary complexity and diversity. However, we
are strongly encouraged that this might
be possible.
Universal featUres
Cities manifest remarkably universal, quan-
tifiable features. This is shown by new analy-
ses of large urban data sets, spanning several
decades and hundreds of urban centres in
regions and countries around the world
from the United States and Europe to China
and Brazil
. Surprisingly, size is the major
determinant of most characteristics of a city;
history, geography and design have second-
ary roles4,6.
Three main characteristics vary system-
atically with population. One, the space
required per capita shrinks, thanks to
denser settlement and a more intense use
of infrastructure. Two, the pace of all socio-
economic activity accelerates, leading to
higher productivity. And three, economic
and social activities diversify and become
more interdependent, resulting in new
forms of economic specialization and cul-
tural expression.
We have recently shown that these general
trends can be expressed as simple math-
ematical ‘laws. For example, doubling the
population of any city requires only about
an 85% increase in infrastructure, whether
that be total road surface, length of electrical
cables, water pipes or number of petrol sta-
. This systematic 15% savings happens
because, in general, creating and operating
the same infrastructure at higher densities
is more efficient, more economically viable,
and often leads to higher-quality services
and solutions that are impossible in smaller
places. Interestingly, there are similar savings
in carbon footprints
— most large, devel-
oped cities are ‘greener’ than their national
average in terms of per capita carbon emis-
sions. It is as yet unclear whether this is also
true for cities undergoing extremely rapid
development, as in China or India, where
data are poor or lacking.
Similar economies of scale are found in
organisms and communities like anthills
and beehives, where the savings are closer
to 20%9. Such regularities originate in the
mathematical properties of the multiple
A unified theory
of urban living
It is time for a science of how city growth affects society
and environment, say Luis Bettencourt and Geoffrey West.
Full content and enhanced
graphics at:
912 | NATURE | VOL 467 | 21 OCTOBER 2010
© 20 Macmillan Publishers Limited. All rights reserved10
networks that sustain life, from the cardio-
vascular to the intracellular
. This suggests
that similar network dynamics underlie
economies of scale in cities.
Cities, however, are much more than giant
organisms or anthills: they rely on long-
range, complex exchanges of people, goods
and knowledge. They are invariably magnets
for creative and innovative individuals, and
stimulants for economic growth, wealth
production and new ideas — none of which
have analogues in biology.
The bigger the city, the more the aver-
age citizen owns, produces and consumes,
whether goods, resources or ideas4. On aver-
age, as city size increases, per capita
socio-economic quantities such as
wages, GDP, number of patents pro-
duced and number of educational
and research institutions all increase
by approximately 15% more than the
expected linear growth4. There is,
however, a dark side: negative met-
rics including crime, traffic conges-
tion and incidence of certain diseases
all increase following the same 15%
. The good, the bad and the ugly
come as an integrated, predictable,
Our work shows that, despite
appearances, cities are approximately
scaled versions of one another (see
graph): New York and Tokyo are, to
a surprising and predictable degree,
nonlinearly scaled-up versions of San Fran-
cisco in California or Nagoya in Japan. These
extraordinary regularities open a window on
underlying mechanism, dynamics and struc-
ture common to all cities.
Deviations from these scaling laws, illus-
trated by the spread of data in the figure,
measure how each city over- or under-per-
forms relative to expectations for its size6.
Relatively large deviations (as much as 30%)
are seen for quantities with small numbers,
such as patents and murders, whereas much
smaller deviations (with variances less than
10%) are seen for economic properties. We
also find that quantities such as GDP are
more variable for urban centres in developing
countries, such as China and Brazil, than for
older cities in developed areas such as North
America or Japan. It is unclear whether this
is a fundamental property of developing
nations or an artefact of data collection.
In biology, the network principles under-
lying economies of scale have two profound
consequences. They constrain both the pace
of life (big mammals live longer, evolve slower,
and have slower heart rates, all to the same
degree9), and the limits of growth (animals
generally reach a stable size at maturity10). In
contrast, cities are driven by social interac-
tions whose feedback mechanisms lead to
the opposite behaviour. The pace of urban life
systematically increases with each expansion
of population size: diseases spread faster,
businesses are born and die more often and
people even walk faster in larger cities, all by
approximately the same 15% rule4. More-
over, this social network dynamic allows the
growth of cities to be unbounded: continuous
adaptation, not equilibrium, is the rule.
Open-ended growth is the primary
assumption upon which modern cities and
economies are based. Sustaining that growth
with limited resources requires that major
innovations — such as those historically asso-
ciated with iron, coal and digital technology
— be made at a continuously accelerating rate.
The time between the ‘Computer Age’ and
the ‘Information and Digital Age’ was some
20 years, compared to thousands of years
between the Stone, Bronze and Iron Ages.
Making major technological paradigm shifts
systematically faster is clearly not sustainable,
potentially leading to collapse of the entire
urbanized socio-economic fabric. Avoiding
this requires understanding whether we can
continue to innovate and create wealth with-
out continuous growth and its compounded
negative social and environmental impacts.
acting on evidence
The job of policy-makers is to enhance the
performance of their city relative to base-
lines for their size defined by scaling laws.
Although a scientific understanding of how
cities work may not be prescriptive for pol-
icy-makers, recent work should help them to
encourage positive urban development.
Our research shows that cities are remark-
ably robust: success, once achieved, is sus-
tained for several decades or longer6, thereby
setting a city on a long run of creativity and
prosperity. A great example of success is
metropolitan San Jose, home to the Silicon
Valley, which has been consistently over-
performing relative to expectations for its size
for at least 50 years, well before the advent of
modern hi-tech industry. Unfortunately, the
reverse is also true: it is very hard to turn
around urban decay swiftly. Ineffective
policy and unrealistic short-term expec-
tations can condemn a city to decades
of under-performance: witness former
industrial cities such as Buffalo, New York.
Today’s rapid development and urbani-
zation provides an opportunity to collect
detailed data that will illuminate the links
between economic development and its
undesirable consequences. Policy initiatives
in developed and developing cities should
be viewed as experiments that, if carefully
designed and measured, can help support
the creation of an integrated, predictive the-
ory and a new science of performance-based
planning. Examples of this approach are
increasingly common, both among
poster children such as Barcelona in
Spain or Curitiba in Brazil, and as part
of new initiatives in New York or Lon-
don. Ideally, by coupling general goals
(such as lower carbon emissions) to
actionable policies and measurable
indicators of social satisfaction, suc-
cesses and failures can be assessed and
corrected for, guiding development of
theory and creating better solutions.
Cities are the crucible of human
civilization, the drivers towards
potential disaster, and the source
of the solution to humanity’s prob-
lems. It is therefore crucial that we
understand their dynamics, growth
and evolution in a scientifically pre-
dictable, quantitative way. The dif-
ference between ‘policy as usual’ and policy
led by a new quantitative understanding of
cities may well be the choice between creat-
ing a “planet of slums” or finally achieving
a sustainable, creative, prosperous, urban-
ized world expressing the best of the human
Luis Bettencourt is a scientist at Los
Alamos National Laboratory and external
professor at the Santa Fe Institute. Geoffrey
West i s dis tinguished profe ssor at the Santa
Fe Institute and senior fellow at Los Alamos
National Laboratory.
e-mail: gbw@santafe-edu
1. Schellnhuber, H. J., Molina, M., Stern, N., Huber,
V. & Kadner, S. (eds) Global Sustainability: A Nobel
Cause (Cambridge Univ. Press, 2010).
2. UN-Habitat. State of the World’s Cities 2010/2011
— Cities for All: Bridging the Urban Divide (2010);
available at
3. Jacobs, J. The Death and Life of Great American
Cities (Random House, 1961).
4. Bettencourt, L. M. A., Lobo, J., Helbing, D.,
Kühnert, C. & West, G. B. Proc. Natl Acad. Sci. USA
104, 7301–7306 (2007).
5. Batty, M. Science 319, 769–771 (2008).
6. Bettencourt, L. M. A., Lobo, J., Strumsky, D. &
West, G. B. PLoS ONE (in the press).
7. Brown, M. A., Southworth, F. & Sarzynski, A. Policy
Soc. 27, 285–304 (2009).
8. Dodman, D. Environ. Urban. 21, 185–201 (2009).
9. West, G. B., Enquist, B. J. & Brown, J. H. Science
276, 122–126 (1997).
10. West, G. B., Brown, J. H. & Enquist, B. J. Nature
413, 628–631 (2001).
Data from 360 US metropolitan areas show that metrics such as
wages and crime scale in the same way with population size.
−2.0 −1.5 −1.0 −0.5 00.5 1.0 1.5 2.0
log (city population/city population average)
log (metric/metric average)
21 OCTOBER 2010 | VOL 467 | NATURE | 913
© 20 Macmillan Publishers Limited. All rights reserved10
... It assumes that the residents of a city have roughly equal numbers of network contacts and that the companies in a specific urban industry have similar levels of economic complexity, and thus-as implied by the theory-have approximately equal levels of productivity. Empirical studies have built on this assumption in their use of city sums and means to capture agglomeration effects, as well as in their interpretations, which focus on the 'average' resident or firm 5,12,13,16 . Prior research therefore implicitly painted a picture in which scaling effects are driven by a homogeneous shift of the whole city distribution as the population grows larger (see Discussion for further elaboration and Supplementary Note 6 in the Supplementary Information for a detailed review of a recent mathematical framework 17 that represents the state of the art). ...
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Theories of urban scaling have demonstrated remarkable predictive accuracy at aggregate levels. However, they have overlooked the stark inequalities that exist within cities. Human networking and productivity exhibit heavy-tailed distributions, with some individuals contributing disproportionately to city totals. Here we use micro-level data from Europe and the United States on interconnectivity, productivity and innovation in cities. We find that the tails of within-city distributions and their growth by city size account for 36–80% of previously reported scaling effects, and 56–87% of the variance in scaling between indicators of varying economic complexity. Providing explanatory depth to these findings, we identify a mechanism—city size-dependent cumulative advantage—that constitutes an important channel through which differences in the size of tails emerge. Our findings demonstrate that urban scaling is in large part a story about inequality in cities, implying that the causal processes underlying the heavier tails in larger cities must be considered in explanations of urban scaling. This result also shows that agglomeration effects benefit urban elites the most, with the majority of city dwellers partially excluded from the socio-economic benefits of growing cities. The authors use large-scale data on urban productivity, innovation and social connectivity, as well as extensive mathematical modelling, and show that power-law urban scaling laws arise out of urban inequalities.
... Urban congestion | Traffic flo w the ory | Tra nsportation | P ha se tra nsitions | S ur face gro wth | N on equilibrium phy sics | Criticality T he remarkable scaling theory for cities [1][2][3][4] proposed by West and coworkers indicates that urban transportation networks are analogous to biological networks inside organisms transporting the energy to survive. As such, urban networks exhibit economies of scale when it comes to infrastructure needs; e.g., doubling the population of a city requires only about 1.8 times the number of gas stations, lane-miles of road, etc. ...
The analogy between the theory of phase transitions in simple fluids and vehicular traffic flow has long been suspected, promising a new level of understanding of urban congestion by standing on one of the firmer foundations in physics. The obstacle has been the interpretation of the thermal energy of the gas-particle system, which remains unknown. This paper proposes the flow of cars through the network as a viable interpretation, where the fundamental diagram for traffic flow would be analogous to the coexistence curve in gas-liquid phase transitions. Thanks to the power-law form of the coexistence curve, it was possible to formalize that the resulting network traffic model belongs to the Kardar-Parisi-Zhang universality class. The scaling relationships arising in this universality class are found to be consistent with West's scaling theory for cities. It is shown that congestion costs (delays + fuel consumption) scale superlinearly with city population, possibly and worryingly more so than predicted by West's theory. Implications for sustainability and resiliency are discussed.
... The need to move from national level to city level (or even further) has been promoted by multiple authors [33,34], besides policymakers (e.g. the EU Directorate General for Regional and Urban Policy along with Joint Research Centre have an "Urban Data Platform Plus" [35] that aims to support "urban and territorial development strategies and the local dimension of Sustainable Development Goals"). Consequently, the use of data and science-based policies is being incorporated in the decision-making process along with the demand of more transparency and accountability [36]. ...
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Cities need to improve sustainability levels demanded by climate change mitigation efforts. The use of big data analytics is crucial for understanding its dynamics and deploying solid public policies. Nevertheless, data availability poses great challenges, being difficult to produce reliable analyses. Delivering trustable cross-sectorial energy datasets with high spatial and temporal resolution is thus critical to provide valuable insights for informed policymaking. This paper describes the MetaExplorer, a GIS-platform, which gathers trustable energy-related datasets, at municipal level for Portugal, providing a user-friendly georeferenced visualisation tool that can be used to derive statistical models, and support policymaking. Publicly available data was collected and cleaned, divided on five thematic areas: energy demand, buildings, mobility, waste management, and socio-economic, while a visualisation tool was developed to provide the possibility to further explore relations between indicators and support the energy transition at local level, delivering customised analyses with a global perception.
... Due to the acceleration of urbanization, urban malaise, suburban sprawl, and other problems have emerged. New analytical methods and tools represented by the modeling approach became a greater necessity in urban planning at that time [24]. At the same time, the modeling approach is no longer regarded as a tool to predict the boundaries of towns but as a way of theoretical research. ...
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The industrial small-town development process in Shandong is influenced by the urban agglomeration strategy and the regional collaborative production, thereby resulting in a challenge of growth boundary planning. How to build a growth forecast decision support system to help small industrial towns maintain sustainable development with limited trial and error costs is an essential topic in the current research of small town-related fields. Empirical analysis reveals that the growth factors of small towns differ from the factors of cities due to the other-organization planning management system and self-organization construction activities that coexist in small towns. Besides, due to the size of small towns, the impact of policy changes in small towns is more significant than in cities. Furthermore, as part of the regional production chain, small industrial towns are most vulnerable to uncertain external disturbances. Therefore, it is necessary to formulate different development scenarios according to possible disturbances and output corresponding development forecasts. The research aims to build a decision-making support system for Shandong’s small-town planning based on an urban modeling approach using geographic information technology and scenario planning. Considering the mutually driving effects of the objective environment and subjective policies of Shandong’s industrial towns, as well as the corresponding dynamic mechanisms and comparing the theoretical basis and limitations of the different modeling approaches, this essay constructs a model system based on a mathematical model and a system dynamics model. It is also an interactive model accompanied by applicable rules and factors so that initial information and relevant development goals can be inputted into the model system to simulate the influence of different policies and identify the small industrial town growth scenarios.
... It is clear that big urban agglomerations have a pivotal role in the accomplishment of such goals as many of them are fundamentally related to human movements, displacement, and interactions (Glaeser, 2012;Sassen, 2019). More in general, it is known that human dynamics are related to the diffusion of viral diseases (Eubank et al., 2004;Colizza et al., 2007;Perkins et al., 2014), to the behavioral responses in case of natural disasters (Bohorquez et al., 2009;Bagrow et al., 2011), to the optimization of traffic volumes (Batty, 2013;Mazzoli et al., 2019), to the economic growth, innovation and social integration (Bettencourt et al., 2007;Pan et al., 2013;Schläpfer et al., 2014), to the severity of air pollution and the consumption of energy, water and other resources (Bettencourt et al., 2007;Bettencourt & West, 2010). ...
Urban agglomerations are constantly and rapidly evolving ecosystems, with globalization and increasing urbanization posing new challenges in sustainable urban development well summarized in the United Nations' Sustainable Development Goals (SDGs). The advent of the digital age generated by modern alternative data sources provides new tools to tackle these challenges with spatio-temporal scales that were previously unavailable with census statistics. In this review, we present how new digital data sources are employed to provide data-driven insights to study and track (i) urban crime and public safety; (ii) socioeconomic inequalities and segregation; and (iii) public health, with a particular focus on the city scale.
... Several studies have recently extended scaling approaches from biology-where various organismal characteristics scale with size-to the study of cities (Bettencourt et al., 2007;Bettencourt and West 2010;Fragkias et al. 2013;Bettencourt, 2013Bettencourt, , 2020Oliveira et al. 2014;West, 2018;Lobo et al., 2019;. Urban Scaling Theory (UST; a.k.a ...
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Natural and man-made stressors have caused severe uncertainties in the urban environment and in particular urban water systems (UWSs) management. Lack of proper understanding of future uncertainties in urban design would lead to intangible and tangible losses including failure of lifeline infrastructures. Building resilience has started to gain prominence in the past decade as an integral part of sustainable UWSs management in a way that the systems could be functional under standard loadings and adaptive in extreme situations. Entropy and resilience are two related and imperative concepts that seek to quantify the performance of a system in circumstances with high uncertainty. Considering the multidisciplinary nature of these two terms with disparate, even contradictory, definitions in the literature, this chapter presents a review of the basic concepts, various definitions as well as applications in the water resources area with case studies.
Cities have been envisioned as biological organisms as the integral part of nature's energy and material flows. Recent advances in urban scaling research have uncovered systematic changes in socioeconomic rates and infrastructural networks as urban population increases, providing predictive contents for the comparison between cities and organisms. However, it is still unclear how and why larger and smaller cities may differ in their per capita environmental impacts. Here, we study scaling patterns of urban energy, water, and waste flows as well as other relevant measures in Chinese cities. We divide cities into different groups using an algorithm that automatically assigns cities to clusters with distinct scaling patterns. Despite superlinear scaling of urban GDP, as predicted by urban scaling theories, resource consumption, such as the supply of electricity and water, and waste generation, such as wastewater and domestic waste, do not show significant deviations from linear scaling. The lengths of resource pipelines scale linearly in most cases, as opposed to sub-linearity predicted by theory. Furthermore, we show two competing forces underlying the overall observed effects of scale: a higher population density tends to decrease per capita resource consumption and infrastructure provisions, while intensified socioeconomic activities have the opposite effect.
Understanding the co-evolution and organizational dynamics of urban properties (i.e., urban scaling) is the science base for pursuing synergies toward sustainable cities and society. The generalization of urban scaling theory yet requires more studies from various developmental regimes and across time. Here, we extend the universality proposition by exploring the evolution of longitudinal and transversal scaling of Chinese urban attributes between 1987 and 2018 using a global artificial impervious area (GAIA) remotely sensed dataset, harmonized night light data (NTL), and socioeconomic data, and revealed agreements and disagreements with theories. The superlinear relationship of urban area and population often considered as an indicator of wasting land resources (challenging the universality theory βc = 2/3), is in fact the powerful impetus (capital raising) behind the concurrent superlinear expansion of socio-economic metabolisms (e.g., GDP, total wage) in a rapidly urbanizing country that has not yet reached equilibrium. Similarly, infrastructural variables associated with public services, such as hospitals and educational institutions, exhibited some deviations as well and were scaled linearly. However, the temporal narrowing of spatial deviations, such as the decline in urban land diseconomies of scale and the stabilization of economic output, clearly indicates the Chinese government's effort in charting urban systems toward balanced and sustainable development across the country. More importantly, the transversal sublinear scaling of areal-based socio-economic variables was inconsistent with the theoretical concept of increasing returns to scale, thus validating the view that a single measurement cannot unravel the intricate web of diverse urban attributes and urbanization. Our dynamic urban scaling analysis across space and through time in China provides new insights into the evolving nexus of urbanization, socioeconomic development, and national policies.
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Allometric scaling relations, including the 3/4 power law for metabolic rates, are characteristic of all organisms and are here derived from a general model that describes how essential materials are transported through space-filling fractal networks of branching tubes. The model assumes that the energy dissipated is minimized and that the terminal tubes do not vary with body size. It provides a complete analysis of scaling relations for mammalian circulatory systems that are in agreement with data. More generally, the model predicts structural and functional properties of vertebrate cardiovascular and respiratory systems, plant vascular systems, insect tracheal tubes, and other distribution networks.
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Several equations have been proposed to describe ontogenetic growth trajectories for organisms justified primarily on the goodness of fit rather than on any biological mechanism. Here, we derive a general quantitative model based on fundamental principles for the allocation of metabolic energy between maintenance of existing tissue and the production of new biomass. We thus predict the parameters governing growth curves from basic cellular properties and derive a single parameterless universal curve that describes the growth of many diverse species. The model provides the basis for deriving allometric relationships for growth rates and the timing of life history events.
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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 worldwide 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, beta, that fall into distinct universality classes. Quantities reflecting wealth creation and innovation have beta approximately 1.2 >1 (increasing returns), whereas those accounting for infrastructure display beta approximately 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 beta<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.
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Despite a century of effort, our understanding of how cities evolve is still woefully inadequate. Recent research, however, suggests that cities are complex systems that mainly grow from the bottom up, their size and shape following well-defined scaling laws that result from intense competition for space. An integrated theory of how cities evolve, linking urban economics and transportation behavior to developments in network science, allometric growth, and fractal geometry, is being slowly developed. This science provides new insights into the resource limits facing cities in terms of the meaning of density, compactness, and sprawl, and related questions of sustainability. It has the potential to enrich current approaches to city planning and replace traditional top-down strategies with realistic city plans that benefit all city dwellers.
Cities are often blamed for high levels of greenhouse gas emissions. However, an analysis of emissions inventories shows that — in most cases — per capita emissions from cities are lower than the average for the countries in which they are located. The paper assesses these patterns of emissions by city and by sector, discusses the implications of different methodological approaches to producing inventories, identifies the main drivers for high levels of greenhouse gas production, and examines the role and potential for cities to reduce global greenhouse gas emissions.
The world's metropolitan carbon footprints have distinct geographies that are not well understood or recognized in debates about climate change, partly because data on greenhouse gas emissions is so inadequate. This article describes the results of the most comprehensive assessment of carbon footprints for major American metropolitan areas available to date, focusing on residential and transportation carbon emissions for the largest 100 metropolitan areas in the United States. These findings are put into the context of efforts across the country and the globe to characterize carbon impacts and policy linkages.
Título de cubierta: The death and life of great American cities : the failure of town planning Reprinted: 1974
Global Sustainability: A Nobel Cause
  • H. J. Schellnhuber
  • M. Molina
  • N. Stern
  • V. Huber
  • S. Kadner
  • G B West
  • J H Brown
  • B Enquist
West, G. B., Brown, J. H. & enquist, B. J. Nature 413, 628–631 (2001).