Economic growth is conventionally analyzed at the national level, yet cities generate the bulk of global output. Here we construct GDP trajectories for 8,808 functional urban areas (FUAs) across 165 countries over 1993-2019 using satellite-derived nighttime light data and identify 17 distinct, persistent growth regimes through clustering of full temporal trajectories. Rather than converging toward a common frontier, FUAs inhabit distinct economic niches-analogous to ecological niches-defined by shared volatility profiles, shock responses, and long-run dynamics that transcend national boundaries. Cities within the same country frequently belong to different regimes, while structurally similar cities on different continents share the same one; regime membership explains 16% of within-country growth variance beyond country fixed effects. National-level convergence emerges as an aggregation artifact: conditional convergence operates within regimes, not globally. A directed propagation network reveals that shocks transmit along lines of structural similarity rather than geographic proximity, with advanced economies exporting disturbances and emerging economies absorbing or amplifying them. Within-country spatial inequality declines with industrialization maturity, consistent with growth initially concentrating in leading cities before diffusing across the urban system. The global economy is better understood as an ecology of heterogeneous urban growth regimes than as a collection of nations on a shared development path.
This study investigates the complex dynamics of new-type urbanization in resource-based county-level cities, using Wuan City in Hebei Province, China, as a representative case. As China pursues a high-quality development agenda, cities historically dependent on resource extraction face profound challenges in achieving sustainable and inclusive urban growth. This research employs a multi-method approach—including Theil index analysis, industrial shift-share analysis, a Cobb-Douglas production function model, and a composite urbanization index—to quantitatively diagnose the constraints on Wuan’s development and assess its transformation efforts. Our empirical results reveal a multifaceted situation: while the urban-rural income gap has narrowed, rural income streams remain fragile. A shift-share analysis indicates that although Wuan’s traditional industries have regained competitiveness, the city’s economic structure is still burdened by a persistent negative structural component, hindering diversification. Furthermore, the economy exhibits characteristics of a labor-intensive growth model with inefficient capital deployment. These underlying issues are reflected in a comprehensive urbanization index that, after a period of rapid growth, has recently stagnated, signaling the exhaustion of the city’s traditional development mode. In response, Wuan attempts an “industrial transformation-driven new-type urbanization” path. This study details the three core strategies being implemented: (1) incremental population urbanization through development at the urban fringe and in industrial zones; (2) in-situ urbanization of the existing rural population; and (3) the cultivation of specialized “characteristic small towns” to create new, diversified economic nodes. The findings from Wuan offer critical, actionable lessons for other resource-dependent regions. The case demonstrates that successful urban transformation requires not only industrial upgrading but also integrated, spatially aware planning and robust institutional support. We conclude that while Wuan’s model provides a valuable reference, its strategies must be adapted to local contexts, emphasizing the universal importance of institutional innovation, human capital investment, and a people-centered approach to achieving resilient and high-quality urbanization.
Abstract This study proposes a new theory of sustainable city size: the condition where a city’s actual population aligns with its theoretical capacity to function effectively. Drawing from four foundational theories (locational fundamentals, increasing returns, central place, and central flow), the study develops a conceptual framework to estimate theoretical city size using data from 655 Urban Centres and Localities (UCLs) in Australia. It examines how deviations of actual size from this theoretical size influence sustainability outcomes, using rent, walking-to-work rates, and multi-vehicle household share as proxies for economic, environmental, and socio-environmental sustainability. Results show that UCLs within ±4% of their theoretical size achieve optimal outcomes across all indicators. Nationally, achieving equilibrium could save $5.3 billion in annual rent, generate 44,000 additional daily walking trips, and reduce multi-vehicle dependency in 275,000 households. These findings support the proposed theory and offer a practical tool to align cities with their systemic capacity.
Helge Ritter, Otthein Herzog, Kurt Rothermel
et al.
We attempt to take a comprehensive look at the challenges of representing the spatio-temporal structures and dynamic processes defining a city's overall characteristics. For the task of urban planning and urban operation, we take the stance that even if the necessary representations of these structures and processes can be achieved, the most important representation of the relevant mindsets of the citizens are, unfortunately, mostly neglected. After a review of major "traditional" urban models of structures behind urban scale, form, and dynamics, we turn to major recent modeling approaches triggered by recent advances in AI that enable multi-modal generative models. Some of these models can create representations of geometries, networks and images, and reason flexibly at a human-compatible semantic level. They provide huge amounts of knowledge extracted from Terabytes of text and image documents and cover the required rich representation spectrum including geographic knowledge by different knowledge sources, degrees of granularity and scales. We then discuss what these new opportunities mean for the modeling challenges posed by cities, in particular with regard to the role and impact of citizens and their interactions within the city infrastructure. We propose to integrate these possibilities with existing approaches, such as agent-based models, which opens up new modeling spaces including rich citizen models which are able to also represent social interactions. Finally, we put forward some thoughts about a vision of a "social AI in a city ecosystem" that adds relevant citizen models to state-of-the-art structural and process models. This extended city representation will enable urban planners to establish citizen-oriented planning of city infrastructures for human culture, city resilience and sustainability.
Filippo Marchesani, Francesca Masciarelli, Andrea Bikfalvi
The rise of smart cities represents a significant trend in urban development. However, only in recent years has attention shifted toward the international promotion of these cities. Despite ongoing academic discussions on the impact of smart city development on urban environments, the global recognition of smart cities remains uncertain due to their multidisciplinary nature. To address this, we conducted a systematic literature review of articles published in top-tier peer-reviewed journals from 2008 to December 2021, offering a comprehensive analysis of the existing literature.
Carbon Monoxide (CO) is a dominant pollutant in urban areas due to the energy generation from fossil fuels for industry, automobile, and domestic requirements. Forecasting the evolution of CO in real-time can enable the deployment of effective early warning systems and intervention strategies. However, the computational cost associated with the physics and chemistry-based simulation makes it prohibitive to implement such a model at the city and country scale. To address this challenge, here, we present a machine learning model based on neural operator, namely, Complex Neural Operator for Air Quality (CoNOAir), that can effectively forecast CO concentrations. We demonstrate this by developing a country-level model for short-term (hourly) and long-term (72-hour) forecasts of CO concentrations. Our model outperforms state-of-the-art models such as Fourier neural operators (FNO) and provides reliable predictions for both short and long-term forecasts. We further analyse the capability of the model to capture extreme events and generate forecasts in urban cities in India. Interestingly, we observe that the model predicts the next hour CO concentrations with R2 values greater than 0.95 for all the cities considered. The deployment of such a model can greatly assist the governing bodies to provide early warning, plan intervention strategies, and develop effective strategies by considering several what-if scenarios. Altogether, the present approach could provide a fillip to real-time predictions of CO pollution in urban cities.
Mirko Degli Esposti, Armando Bazzani, Chiara Dellacasa
et al.
This paper introduces a scalable methodology for the objective analysis of quality metrics across six major Italian metropolitan areas: Rome, Bologna, Florence, Milan, Naples, and Palermo. Leveraging georeferenced Street View imagery and an advanced Urban Vision Intelligence system, we systematically classify the visual environment, focusing on key metrics such as the Pavement Condition Index (PCI) and the Façade Degradation Score (FDS). The findings quantify Structural Heterogeneity (Spatial Variance), revealing significant quality dispersion (e.g., Milan $σ^2_{\mathrm{PCI}}=1.52$), and confirm that the classical Urban Gradient -- quality variation as a function of distance from the core -- is consistently weak across all sampled cities ($R^2 < 0.03$), suggesting a complex, polycentric, and fragmented morphology. In addition, a Cross-Metric Correlation Analysis highlights stable but modest interdependencies among visual dimensions, most notably a consistent positive association between façade quality and greenery ($ρ\approx 0.35$), demonstrating that structural and contextual urban qualities co-vary in weak yet interpretable ways. Together, these results underscore the diagnostic potential of Vision Intelligence for capturing the integrated spatial and morphological structure of Italian cities and motivate a large national-scale analysis.
Hassan Mohammadian Mosammam, Jamileh Tavakoli Nia, H. Khani
et al.
Abstract As a response to the challenge of rapid pace of urbanization and lack of reliable data for environmental and urban planning, especially in the developing countries, this paper evaluates land use/cover change (LCLU) and urban spatial expansion, from 1987 to 2013, in the Qom, Iran, using satellite images, field observations, and socio-economic data. The supervised classification technique by maximum likelihood classifier has been employed to create a classified image and has been assessed based on Kappa index. The urban sprawl was also measured using Shannon’s entropy based on its primary spatial forms. To our knowledge, measuring urban sprawl based on its spatial forms would contribute to prioritizing policies and specific regulations in dealing with its dominant form. Finally, LCLU change and urban growth were simulated for 2022, using CA-Markov model. The results revealed that dramatic growth of built-up areas has led to a significant decrease in the area of agriculture, gardens and wasteland, from 1987 to 2013. The obtained relative entropy values have indicated that the Qom city has experienced increasing urban sprawling over the last three decades. The continuous linear and non-continuous linear developments along the major roads and highways are the dominant forms of sprawl in Qom city. The CA-Markov model estimated that this unsustainable trend will continue in the future and built-up areas will be increased by 10% by 2022 resulting in potential loss of 438.03 ha agriculture land, 638.37 ha wasteland, and 17.01 ha gardens. Those results indicated the necessity of appropriate policies and regulations particularly for limiting linear sprawl along the main roads.
The objective of this article is to understand processes and mechanisms that make urban policy instruments legitimize public interest being obscured by the hegemony of private actors, suggesting dissonances and distancing of these instruments from the urban plans and projects proposed for Recife (2000-2023). These mismatches and their prevalence are exemplified in the production of the city that accompanies the river and sea coast in the central area, assuming that investments by private actors in the historic centres are directly linked to and favoured by public policies (or their inability to counterbalance real estate advancement), resulting in the valuation of land not being the object of fair redistribution driven by urban policy. It is based on the fact that the urban space is the object and result of conflict and socio-spatial inequality, and that within the framework of a monopolistic and oligopolistic capitalist practice, the interests of real estate developers and developers, and the privatization of public lands, result in pressures from private agents on the State and society.
Aesthetics of cities. City planning and beautifying, Urban groups. The city. Urban sociology
Francesco Marzolla, Matteo Bruno, Hygor Piaget Monteiro Melo
et al.
The 15-minute city concept, which advocates for cities where essential services are accessible within a 15-minute walk or bike ride, has gained significant attention in recent years. However, despite being celebrated for promoting sustainability, large-scale empirical evaluations of the effectiveness of the 15-minute concept in reducing emissions are lacking. To address this gap, we investigate whether cities with better walking accessibility, like 15-minute cities, are associated with lower transportation emissions. Comparing 664 cities worldwide, we find that cities with better walking accessibility to services emit less CO$_2$ per capita for transport. Moreover, we observe that among cities with similar average accessibility, those that span larger areas tend to emit more. Our findings highlight the effectiveness of decentralised urban planning, especially the proximity-based 15-minute city, in promoting sustainable mobility. However, they also emphasise the need to integrate local accessibility with urban compactness and efficient public transit, which are vital in large cities.
Yvonne Jansen, Federica Bucchieri, Pierre Dragicevic
et al.
We present the results of a brainstorming exercise focused on how situated visualizations could be used to better understand the state of the environment and our personal behavioral impact on it. Specifically, we conducted a day long workshop in the French city of Bordeaux where we envisioned situated visualizations of urban environmental footprints. We explored the city and took photos and notes about possible situated visualizations of environmental footprints that could be embedded near places, people, or objects of interest. We found that our designs targeted four purposes and used four different methods that could be further explored to test situated visualizations for the protection of the environment.
Abdulaziz I. Almulhim, S. Bibri, Ayyoob Sharifi
et al.
More than 59 million people reside in the six member countries of the Gulf Cooperation Council (GCC) (the United Arab Emirates, Bahrain, Kuwait, Oman, Qatar, and Saudi Arabia). The rate of urbanization is more than 80% in each of these countries. To better understand the trends and knowledge structures and to aid policy design and implementation, more research is needed on the topic of urbanization in GCC countries. In order to address this knowledge gap, bibliometric analysis and scientific mapping procedures utilizing VOSviewer were employed. A total of 415 academic papers covering four decades, from 1980 to 2021, were collected from the Web of Science database and split into three time periods: 1980–2017, 2018–2019, and 2020–2021. The findings indicate that the topics related to sustainable development, environmental regulations, renewable energy, and smart cities have received the most attention. In addition, land use planning, urban growth, and energy consumption have been dominant themes over different periods. Several intertwined factors have contributed to the evolution of research over these periods. These include the widespread diffusion of the sustainability agenda, the rise of advanced ICT, and the escalating rate of urbanization. It can also be explained by the fact that the world has been grappling with numerous environmental challenges, increasingly requiring innovative solutions for sustainability. The findings of this study can be used to develop better strategies for sustainable urban development in the region.
TeMA Journal’s Special Issue Burn or sink - Planning and managing the land features a collection of eight original papers. These were written specifically for this issue following the call for papers launched in October 2022. The papers present ideas, theories, empirical insights, methodologies, experiences, and techniques about policy issues, best practices, and research findings on the Special Issue themes. TeMA Journal has already shown extensive interest in these aspects. Over its 16-year lifespan, the journal has explored broad themes that characterize today’s environmental crisis, with the aim of outlining new planning paths. For the first time, the journal’s editorial staff is proposing a Special Issue aimed at deepening the topic by soliciting articles focused on scientific aspects, the development of innovative practices, and the role of social behaviors.
Transportation engineering, Urbanization. City and country
With this volume - Conversations with TeMA - the Journal opens a new editorial line specifically dedicated to promoting and disseminating the discussion between worldwide researchers on specific issues concerning the contents, methods and timing of our work.
This first experience is dedicated to a deepening, in an interview formula, on the future of spatial planning in Italy both from a regulatory and technical-disciplinary perspective, also concerning what is happening in other countries. In line with the aims we had set, we decided to involve, in this first phase, both colleagues working in Italian universities and those working in foreign universities and research centres.
This contribution is by Donatella Cialdea, Full Professor in Urban Planning, L.a.co.s.t.a. Laboratory Director, University of Molise
Transportation engineering, Urbanization. City and country
Pablo Cabrera-Barona, Gabriel Gaona, Andrea Carrión
The restrictions triggered by the COVID-19 pandemic, especially during the first weeks of confinement in 2020, entailed marked changes concerning urban socio-spatial relations. This article analyzes perceptions of the importance of public space, neighbors' support, neighborhood safety, and home safety before and during the initial months of the COVID-19 lockdown. We conducted an online survey between March and April 2020 in Quito, Ecuador, and applied quantitative and spatial methods to analyze the perceptions. The results show statistically significant differences in neighbors’ support, home safety, and neighborhood safety between normal days and lockdown days. The perceptions of the public space as non-important before the lockdown and the perceptions of not being safe at home or in the neighborhood are spatially random, not concentrated in a specific area of the city. Our findings also show that gender, the importance of public space during normal days, and the willingness of neighbors to support each other on lockdown days could explain the perception of the importance of public space on lockdown days. This research provides unique information to contribute with perspectives and discussions of public space and social dynamics in pandemic and post pandemic times.
Urbanization. City and country, Political institutions and public administration (General)
This paper situates the rise of city-regionalism in China in the context of the Chinese Communist Party (CCP)’s approach to the urban question since 1949. From strictly controlling urbanization during the first two decades of socialist central planning, the Chinese state now promotes mega city-regionalization (literally in Chinese, city clusters) as a vehicle for internationalizing China’s economy. A reframed urban question in China today emerges from the ongoing tension between city-regional growth, on the one hand, and the emergence of new political interests in the urban living place around the collective provision of services, social and environmental inequalities, and citizen/resident representation in urban governance, on the other. The planetary scope of urbanization notwithstanding, differences in the national political context are crucial for explaining the full diversity of city-regional development processes and outcomes in different countries. The city-regional domain provides an exciting opportunity for urban scholars to examine the changing nature of the urban question in China in the context of an emergent ‘world of city-regionalisms’.