Designing a circular cities declaration for Japan building on the European Union's case study

Japan is progressing towards its circular economy (CE) goals as many of its cities have adopted circular city (CC) policies and programs, although further progress is constrained as a result of the lack of a common framework. A novel framework was proposed with the "European circular cities declaration" (ECCD) (2020), consisting of a list of 10 principles committing to integrate circularity into the city's design, development, and management. As a foremost finding, and building on the authors' previous studies of Japan's CE and CC, this work shaped a circular cities declaration (CCD) for Japan following a triple-axis methodology; It (1) evaluates the ECCD as a baseline, (2) adapts it to Japan's unique socio-economic landscape, and (3) considers the three pillars of sustainable development, offering practical guidance for governments facing similar challenges. This environmental management tool goes beyond the EU one providing a model of hybrid governance and monitoring and evaluation mechanism. The resulting declaration is intended for the government to facilitate a transition from insulated CE policies to holistic CC ones, but also for businesses, academia, and communities; Thus, it may aid in endorsing a cities' common framework and shared vision to harness the potential of CC to address environmental issues, foster innovation and collaboration toward a resilient future in Japan.

Identifying potential uses for green roof discharge based on its physical-chemical-microbiological quality

Green roofs are promising tools in sustainable urban planning, offering benefits such as stormwater management, energy savings, aesthetic appeal, and recreational spaces. They play a crucial role in creating sustainable and resilient cities, providing both environmental and economic advantages. Despite these benefits, concerns persist about their impact on water quality, especially for non-potable use, as conflicting results are found in the literature. This study presents a comparative analysis of the quantity and quality of water drained from an extensive green roof against an adjacent conventional rooftop made of fiber-cement tiles in subtropical Brazil. Over a 14-month period, the water drained from both roofs was evaluated based on physical (turbidity, apparent color, true color, electrical conductivity, total solids, total dissolved solids, suspended solids), chemical (pH, phosphate, total nitrogen, nitrate, nitrite, chlorides, sulfates, and BOD), microbiological (total coliforms and E. coli), and metal (copper, iron, zinc, lead, and chrome) concentration parameters. The discharge from the green roof was 40% lower than its counterpart measured at the control roof, while the water quality from both roofs was quite similar. However, the green roof acted as source of chlorides, electrical conductivity, color, BOD, total hardness, E. coli, phosphate, sulfate, and turbidity. On the other side, the green roof neutralized the slightly acidic character of rainwater, showcasing its potential to mitigate the effects of acid rain. The study's results underscored that the water discharged from the green roof generally aligned with non-potable standards mandated by both Brazilian and international regulations. However, the findings emphasized the imperative need for pre-treatment of the green roof discharge before its utilization, specifically adjusting parameters like turbidity, BOD, total coliforms, and E. coli, which were identified as crucial to ensure water safety and compliance with non-potable use standards.

Mapping and monitoring land use land cover dynamics employing Google Earth Engine and machine learning algorithms on Chattogram, Bangladesh

Land use land cover change (LULC) significantly impacts urban sustainability, urban planning, climate change, natural resource management, and biodiversity. The Chattogram Metropolitan Area (CMA) has been going through rapid urbanization, which has impacted the LULC transformation and accelerated the growth of urban sprawl and unplanned development. To map those urban sprawls and natural resources depletion, this study aims to monitor the LULC change using Landsat satellite imagery from 2003 to 2023 in the cloud-based remote sensing platform Google Earth Engine (GEE). LULC has been classified into five distinct classes: waterbody, build-up, bare land, dense vegetation, and cropland, employing four machine learning algorithms (random forest, gradient tree boost, classification & regression tree, and support vector machine) in the GEE platform. The overall accuracy (kappa statistics) and the receiver operating characteristic (ROC) curve have demonstrated satisfactory results. The results indicate that the CART model outperforms other LULC models when considering efficiency and accuracy in the designated study region. The analysis of LULC conversions revealed notable trends, patterns, and magnitudes across all periods: 2003-2013, 2013-2023, and 2003-2023. The expansion of unregulated built-up areas and the decline of croplands emerged as primary concerns. However, there was a positive indication of a significant increase in dense vegetation within the study area over the 20 years.

How robust are current narratives to deal with the urban energy-water-land nexus?

Current energy, water, and land (EWL) nexus research treats all resources equally, causing bias in complicated nexus studies. To make the analysis robust, we consider resource endowment and significance. Here, we provide a methodological framework where the urban industrial resource nexus strength is constructed and assign weights to resources according to policies, describing resource efficiency and representing it in ternary diagrams to assess the urban industrial nexus innovatively. Results showed that energy drives urban development under all weights, with energy resource efficiency exceeding 60%. From consumption-based accounting, energy continues to dominate most industries under physical weightings but emphasizes the significance of water and land. While, under economic weightings, land supplants energy's dominance in specific sectors. Setting weights helps understand resource interaction, establish synergy based on urban development objectives, and minimize robustness. Our findings provide quantitative evidence for assessing urban resource efficiency to highlight priority sectors for intervention in urban decision-making.

Relationships between urban expansion and socioenvironmental indicators across multiple scales of watersheds: a case study among watersheds running through China

Understanding the relationships between urban expansion and social/environmental features is fundamental to managing watershed and urban expansion. However, such relationships remain unclear, especially across multiple scales of watersheds. Here, we quantified the correlation between urban expansion measures and 255 socioenvironmental indicators across three scales of watersheds running through China (20, 103, and 349 watersheds) during 1992-2016 and analyzed their scaling relations. The results showed that the number of indicators showing a significant correlation with the area and speed of urban expansion increased from 132 and 153 to 234 and 237, respectively, from level 1 to level 3 watersheds. Among these indicators, urban expansion was significantly correlated with indicators of climate and anthropogenic impact. From a large scale (level 1 watershed) to a small scale (level 3 watershed), 104 and 84 socioenvironmental indicators shifted from uncorrelated to significantly correlated with urban expansion area and speed. The constraint line analysis further confirmed that some relationships were nonlinear, which suggested that the drivers and impacts of urban expansion have scaling effects. We argue that it is crucial to consider the scaling effects of urban expansion when we formulate urban or watershed management plans.

Dynamic multi-dimensional scaling of 30+ year evolution of Chinese urban systems: Patterns and performance

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 β_c = 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.

Urban sustainability and resilience: What the literature tells us about "lock-ins"?

Inherited system features and challenges that can hinder urban planning initiatives must be taken into consideration before a path towards a sustainable future can be established. By putting the lock-in effect under scrutiny, it is possible to gain valuable insight to emphasize positive lock-ins and to prevent maladaptation and unsustainable solutions. This paper aims to review the current trends of urban studies regarding sustainability, resilience, and the lock-in effect, focusing on both hot topics and mutual integration by following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses for Scoping Reviews (PRISMA-ScR protocol) and analyzing the top-cited articles on these topics from 2015 to 2021 in the Web of Science database. Based on the revised literature, the potential lock-ins of climate-friendly and sustainable urban development are not adequately discussed. Moreover, while urban sustainability and resilience are often treated as overlapping areas, there is a lack of publications that carefully examine their interlinked long-term perspectives for any hindering effects.

Environmental justice in a very green city: Spatial inequality in exposure to urban nature, air pollution and heat in Oslo, Norway

Poorer citizens are often more exposed to environmental hazards due to spatial inequalities in the distribution of urban blue-green space. Few cities have managed to prevent spatial and social inequality despite sustainable development strategies like compact city planning. We explore whether environmental injustice exists in a city where one would least expect to find it: a city with abundant nature, an affluent population governed by a left leaning social democratic city council, and an aggressive densification strategy; Oslo, Norway. Green space was measured with a satellite-derived vegetation index which captures the combined availability of gardens, street trees, parks and forest. Blue space was defined by the proximity of residential areas to the closest lake, river or fjord. We found that poorer city districts, often with greater immigrant populations, have less available blue-green spaces and are disproportionately exposed to hazardous air pollution levels, but not extreme heat compared to wealthier city districts. Citizens living within 100 m of a water body are likely to earn US$ 20,000 more per year than citizens living 500 m away from water, and a US$ 3000 increase in annual income corresponds to a 10 % increase in green space availability. Hazardous air pollution concentrations in the poorest city districts were above levels recommended by the WHO and Oslo municipality. Historical trends showed that districts undergoing population densification coincide with the lowest availability of blue-green space, suggesting that environmental justice has been overlooked in compact city planning policy. Despite Oslo's affluence and egalitarian ideals, the patterns of inequality we observed mirror the city's historical east-west class divide and point to spatial concentration of wealth as a core factor to consider in studies of green segregation. Urban greening initiatives in Oslo and other cities should not take spatial equality for granted, and instead consider socio-economic geographies in their planning process.

Scaling of Chinese urban CO2 emissions and multiple dimensions of city size

Cities are both the primary cause of global climate change and the key to the mitigation agenda. China's unprecedented urbanization has paralleled a growth in energy demand and urban areas have emerged as the crux of CO₂ emissions reduction in China. There is a crucial need for policymakers to understand how CO₂ emissions scale with city size and adopt economies of scale (cost savings) for mitigation, particularly through a multidimensional lens of city size. This study reveals a set of scaling relations between urban scope 1 CO₂ emissions and five dimensions of city size in 340 Chinese cities, including population (POP), built-up area (BA), building height (BH), specific built-up area (SBA), and built-up volume (BV). The findings show that CO₂ emissions in Chinese cities scale linearly with POP and BA but sublinearly with BA, SBA, and BV, and more diverse regimes exist across various geographic zones, population hierarchies, administrative hierarchies, and governance contexts. The prevalent sublinear scaling regime between CO₂ emissions and SBA and BV demonstrates the potential importance of optimizing the vertical built-up landscapes for establishing a zero‑carbon society. Furthermore, the top 10 % and bottom 10 % performance of individual cities in emissions identified by the Scale-Adjusted Metropolitan Indicator (SAMI) (the smaller the better) highlights the imprints of the socioeconomic context (e.g., Low Carbon City Initiative) on the scaling of CO₂ emissions in Chinese cities, which is critical for developing decarbonization strategies. Our multidimensional analysis can assist in the local-tailored low-carbon development of Chinese cities.

Analysis of the implementation of urban computing in smart cities: A framework for the transformation of Saudi cities

Smart city development is gaining widespread acceptance as a means of mitigating urban development problems. However, the implementation of smart cities faces challenges, especially in developing countries. Urban computing is regarded as an enabler of innovation and smart city development. This study explores the adoption of urban computing to address the smart city and urban development problems of Saudi cities. Using a systematic review, this study highlights the trends and influential contributions of urban computing to smart city research. It identifies the urban computing framework and uses the framework to analyze the use of urban computing in Saudi cities to promote smart city development and sustainability. While Saudi Arabia has taken notable steps in urban computing, especially in providing services, further steps need to be taken to achieve the transformation into smart sustainable cities.

Seemingly bounded knowledge, trust, and public acceptance: How does citizen's environmental knowledge affect facility siting?

Understanding the mechanism of public perception and behavior towards environmental goods provision is essential for effective sustainable governance. This paper studies how citizens' self-reported environmental knowledge affects their trust in public service providers and subsequently their decisions about accepting the provision of a pollution management facility in their neighborhood. Utilizing unique survey data on the siting of a facility for waste incineration in Guangzhou, China, we find that the public's perceived environmental knowledge damages their trust in the operator, which lowers their acceptance of the facility siting, while damage to their trust in the government is negligible. In addition, we find that citizens' preferences for the type of information disclosed and the channels used for disclosure can affect public trust and thus acceptance of the facility siting. Therefore, policy suggestions for urban planning for sustainability are that the urban planner and policy maker can mitigate the negative consequences of bounded environmental knowledge by ensuring there is appropriate information disclosure. This study broadens our understanding of public recognition and acceptance of environmental goods provision and provides practical suggestions for sustainable development.

Population-environment dynamics across world's top 100 urban agglomerations: With implications for transitioning toward global urban sustainability

Urbanization is a long-term global trend critical for shaping human-Earth sustainability in the Anthropocene. In past decades, much progress has been made in researching urban sustainability, particularly global assessments of the big picture and case studies of individual cities. Here we examine the world's top 100 urban agglomerations (UAs) in terms of size-that rank high on sustainability agendas and cover 28% of the global UA area-regarding four broadly concerned challenges: population shrinkage, slum development, greenness loss, and heat exposure. Instead of merely focusing on global/regional "averages" or individual cases, we take one step further to identify the "anomalies" of urban sustainability among the 100 UAs for each dimension and on the whole as multi-dimensional coupled infrastructure systems. Results show: (1) urban population of the 100 UAs increased by 36% during 2000-2020; (2) urban slums occurred in 85% of 34 examined UAs in the Global South; (3) urban greenness declined in the 100 UAs by 8% during 2000-2019; and (4) 79% of the 100 UAs were projected to have less than 30 EHDs per year during 2021-2030. Our findings provide global baselines for place-based problem-driven policymaking for the examined UAs and suggest improving urban green infrastructure as their top policy imperative. Our findings point to a critical research gap in the urban sustainability literature: Studying sustainability transitions of the "abnormally" sustainable UAs identified in this study that had exceptional performances on the four examined sustainability dimensions, e.g., Beijing of China and Milan of Italy.

Understanding urban sustainability from Mode 2 Science and transdisciplinary education: how Master Thesis Ateliers of the Ghent Stadsacademie tackle wicked issues

The wicked sustainability problems that we are increasingly facing not only require new ways of knowledge production, but also challenge our traditional educational system. More and more importance is attached to educational practices and experiments focusing on transdisciplinary problem framing, a pluralistic search for solutions and active collaboration with various stakeholders throughout society. The aim of this article is to investigate how an inter- and transdisciplinary setting in which students develop master theses can contribute to learning about a specific urban problem and what challenges this transdisciplinary education entails. Starting from relevant theoretical and analytical frameworks, such as Mode 2 Science (Nowotny et al. 2005) and the three-phase model of Lang et al. (2012), we first outline the philosophy and approach of the general setting: the Stadsacademie, a collective learning platform or 'collaboratory' to explore and investigate wicked problems perceived in the city of Ghent (Belgium). To provide more in-depth and refined insights, we focus on an exemplary activity of the Stadsacademie: the Master Thesis Ateliers 'Diversity in Social Housing'. A Master Thesis Atelier (MTA) is a collaborative trajectory of one academic year in which 4 to 8 master students and their supervisors from different disciplinary backgrounds concentrate on one specific urban problem and collaborate with non-academic actors aiming to explore and to impact upon that issue. We conclude this article with overall reflections and suggestions for transdisciplinary approaches within educational practices to tackle wicked sustainability issues.

Developing a method for assessing environmental sustainability based on the Google Earth Engine platform

Environmental sustainability is the foundation and of great significance for the sustainable development of urban agglomerations. Taking the Beijing-Tianjin-Hebei urban agglomeration as an example, we developed a method to effectively assess long-term regional environmental sustainability based on the Google Earth Engine (GEE) platform. We used the GEE to obtain 5206 Landsat remote sensing images in the region from 1983 to 2016 and developed the comprehensive environmental index (CEI) to assess regional environmental sustainability based on the theme-oriented framework proposed by the United Nations Commission on Sustainable Development. We found that the environmental sustainability of the urban agglomeration showed a trend of first rising, then falling, and then rising again in the past 30 years. The average CEI increased from 0.621 to 0.631 from 1985 to 1990, dropped to the lowest value of 0.618 in 2000, and then rose to the highest value of 0.672 in 2015. In particular, the extent of areas in which environmental sustainability improved (56% of the region) was greater than the extent of areas in which environmental deterioration occurred. The environmental sustainability of Hengshui, Xingtai, and Cangzhou in the southeast of the region has been significantly improved. The method proposed in this study provides an automatic, rapid, and extensible way to assess regional environmental sustainability and provides a scientific reference for improving the sustainability of the regional environment.

Water neutrality framework for systemic design of new urban developments

The climate emergency and population growth threaten urban water security in cities worldwide. Growth, urbanisation, and changes to way of life have increased housing demand, requiring cities such as London to increase their housing stock by more than 15% over the next 10 years. These new urban developments will increase water demand, urban flood risk, and river water pollution levels; therefore, an integrated systems-based approach to development and water management is needed. Water Neutrality (WN) has emerged as a concept to frame the concerns about escalating water stresses in cities. We frame WN as a planning process for new urban developments that aims to minimise impacts on urban water security and offset any remaining stresses by retrofitting existing housing stock. In this work, we present a novel systemic design framework for future urban planning called CityPlan-Water, which guides how WN might be achieved to tackle current and future water pressures at a city scale. CityPlan-Water integrates spatial data with an integrated urban water management model, enabling urban design at a systems level and systematic assessment of future scenarios. We define a Water Neutrality Index that captures how successful a given urban planning scenario is in achieving WN and how multiple interventions could be combined at a city scale to improve WN. Results from CityPlan-Water suggest that it will be necessary to retrofit almost the same number of existing homes with WN design options to completely offset the impact imposed by proposed new developments. Combining options such as water efficient appliances, water reuse systems, and social awareness campaigns can offset the impact of new development on water demand by 70%, while to neutralise potential flood risk and water pollution at a city scale, interventions such as rainwater harvesting and Blue Green Infrastructure need to be added both in new urban developments and 432,000 existing London households. We see CityPlan-Water as a tool that can support the transition of urban planning towards using data-driven analysis to effectively design water neutral housing and drive sustainable development.

Assessment of the impact of sensor error on the representativeness of population exposure to urban air pollutants

For the monitoring of urban air pollution, smart sensors are often seen as a welcome addition to fixed-site monitoring (FSM) networks. Due to price and simple installation, increases in spatial representation are thought to be achieved by large numbers of these sensors, however, a number of sensor errors have been identified. Based on a high-resolution modelling system, up to 400 pseudo smart sensors were perturbated with the aim of simulating common sensor errors and added to the existing FSM network in Hong Kong, resulting in 1200 pseudo networks for PM_2.5 and 1040 pseudo networks for NO₂. For each pseudo network, population-weighted area representativeness (PWAR) was calculated based on similarity frequency. For PM_2.5, improvements (up to 16%) to the high baseline representativeness (PWAR = 0.74) were achievable only by the addition of high-quality sensors and favourable environmental conditions. The baseline FSM network represents NO₂ less well (PWAR = 0.52), as local emissions in the study domain resulted in high spatial pollution variation. Due to higher levels of pollution (population-weighted average 37.3 ppb) in comparison to sensor error ranges, smart sensors of a wider quality range were able to improve network representativeness (up to 42%). Marginal representativeness increases were found to exponentially decrease with existing sensor number. The quality and maintenance of added sensors had a stronger effect on overall network representativeness than the number of sensors added. Often, a small number of added sensors of a higher quality class led to larger improvements than hundreds of lower-class sensors. Whereas smart sensor performance and maintenance are important prerequisites particularly for developed cities where pollutant concentration is low and there is an existing FSM network, our study shows that for places with high pollutant variability and concentration such as encountered in some developing countries, smart sensors will provide benefits for understanding population exposure.

Methodological framework for wastewater treatment plants delivering expanded service: Economic tradeoffs and technological decisions

With emerging decarbonization to deploy more integrated waste management, there is a burgeoning need for re-managing waste-related infrastructures in urban environments. Wastewater treatment plants are key contributors to expanded environmental services, but relevant technological decisions and economic tradeoffs have to be assessed from a systems perspective. This study provides a methodological framework that consolidates the multiple technological and economic aspects of system retrofitting for such an evaluation purpose. Complex leachate from refuse transfer stations has been recently identified as the decarbonization roadblock of urban waste management, and it was chosen for investigations by this new methodological approach. The system impacts by complex leachate on the existing facilities were validated by experimental trials. To derive the financial outlooks for decision making, the evaluation matrix includes the quantitative impacts of bioenergy profiles, energy balance analysis of biogas utilization methods, needs of system retrofitting, economic factors, and their uncertainties. Due to the detected inefficiency of bioenergy recovery, bioinformatic analysis was proceeded for understanding the underlying mechanism to propose a mitigation solution. Overall, the methodological framework can provide a quantitative assessment of the centralized capability of wastewater treatment plants for systems planning in the new policy agenda of urban decarbonization, where the methodological potentials of expanded framework applications are also highlighted.

COVID-19 and the compact city: Implications for well-being and sustainable urban planning

This paper provides new evidence on the role of city planning, urban form, and built environment characteristics in health and well-being during the coronavirus disease (COVID-19) pandemic. Based on survey and geographic information systems (GIS) data from Oslo and Viken in Norway, the paper investigates changes in health and well-being due to COVID-19 and how the compact city and its characteristics relate to these changes. Findings indicate that self-reported measures of health and well-being worsened due to COVID-19. The most substantial changes were reported for life satisfaction, anxiety, and satisfaction with leisure, personal relationships, and vacations. General health, happiness, and satisfaction with income also declined during COVID-19 in comparison with pre-COVID-19 times. Overall, residents of compact neighborhoods reported lower well-being during COVID-19 compared to residents of lower-density neighborhoods. Important compact city characteristics - higher neighborhood density, reliance on public transport, smaller dwellings, and less green space - were negatively associated with well-being and health outcomes during COVID-19. In contrast, another compact city attribute, the presence of numerous local facilities, was positively linked to well-being and health during COVID-19. Based on these findings, the paper presents possible implications for sustainable urban planning and compact cities.

Pro-environmental habits: An underexplored research agenda in sustainability science

Habits are the fundamental basis for many of our daily actions and can be powerful barriers to behavioural change. Still, habits are not included in most narratives, theories, and interventions applied to sustainable behaviour. One reason societies struggle to reach policy goals and people fail to change towards more pro-environmental lifestyles might be that many behaviours are now bound by strong habits that override knowledge and intentions to act. In this perspective article, we provide three arguments for why pro-environmental habits are a needed research agenda in sustainability science: (1) habit theory highlights how behaviour is heavily reliant on automatic processes, (2) the environmental context sets boundary conditions for behaviour, shape habits, and cues action responses, and (3) our habits and past behaviour shape our values and self-identity. These arguments highlight the transformative potential of looking at sustainable behaviours through a habit lens. We believe a research agenda on pro-environmental habits could generate a more holistic understanding of sustainable behaviours and complement today's dominating approaches which emphasize reasoned decisions and intrinsic motivations such as values, norms, and intentions to understand and predict pro-environmental behaviour. We highlight evident knowledge gaps and practical benefits of considering habit theory to promote pro-environmental behaviours, and how habit architecture could be utilized as a strong leverage point when designing, modifying, and building urban environments.

How did the COVID-19 pandemic impact urban green spaces? A multi-scale assessment of Jeddah megacity (Saudi Arabia)

The outbreak of the COVID-19 pandemic emerged as a global public health threat. In this crisis period, urban parks provided multiple ecosystem services and direct/indirect benefits to mental and physical health. However, the use patterns, attitudes, and perceptions of urban park visitors remained unexplored in Saudi cities. This study aimed to find out the use patterns, attitudes, and perceptions of people regarding urban parks during the COVID-19 pandemic, and the findings were compared with non-pandemic periods. Two urban parks (Al Masarah Garden and Al Jamaa Garden) in Jeddah megacity (Saudi Arabia) were assessed, and 215 respondents were surveyed to fulfil the objectives of the study. The study applied a questionnaire survey and field observations to understand the impact of the COVID-19 pandemic on the use patterns, attitudes, and perceptions of urban park visitors. Non-parametric tests (Kruskal-Wallis and Mann-Whitney tests) were performed to find out the impact of sociodemographic factors (such as age, gender, and education). From the results, it was found that the COVID-19 pandemic had a substantial impact on the use, attitudes, and perceptions of urban parks in comparison with non-pandemic periods. The number of park visitors decreased during the COVID-19 pandemic, but urban parks were crucial to people's mental and physical well-being. The findings of this study may help to understand the importance of urban parks as green spaces and to implement measures to enhance the quality and quantity of urban green spaces in Saudi cities.

Transformative, interdisciplinary and intercultural learning for developing HEI students' sustainability-oriented competences: a case study

The literature has produced relevant theoretical insights into pedagogical frameworks, tools and competences that would be best suited to teach sustainability at higher education (HE). This article contributes to such a discussion using a course on sustainability developed by us as a case study. Two research questions are tackled in this article: (1) How to empower students to address urban sustainability challenges through the inclusion of transformative, interdisciplinary and intercultural learning into the current HE system? (2) Which pedagogical tools can be used to develop students' sustainability-oriented competences? To address the research questions, the case study consists of two parts. First, by reflecting on the course design, this article aims to shed light on the benefits and challenges of transformative pedagogy and of an interdisciplinary and intercultural framework. Second, by analyzing students' learning diaries (N = 36) using thematic analysis, this article offers insights into some of the students' learning process, allowing us to assess the strengths and weaknesses of the course design as well as draw implications to improve and renew courses on sustainability in HE. The findings from the learning diaries indicate the students' thirst for formal knowledge on sustainability, which they connected to their professional development and yearning for action. The learning diaries also suggest students' increasing awareness of sustainability as a systemic and structural issue during the course, which aligns with the transformative learning framework used. Finally, this study emphasizes the need for structural support to meaningfully integrate sustainability in HE curricula and teaching practices.

Spatial disparities of self-reported COVID-19 cases and influencing factors in Wuhan, China

The lack of detailed COVID-19 cases at a fine spatial resolution restricts the investigation of spatial disparities of its attack rate. Here, we collected nearly one thousand self-reported cases from a social media platform during the early stage of COVID-19 epidemic in Wuhan, China. We used kernel density estimation (KDE) to explore spatial disparities of epidemic intensity and adopted geographically weighted regression (GWR) model to quantify influences of population dynamics, transportation, and social interactions on COVID-19 epidemic. Results show that self-reported COVID-19 cases concentrated in commercial centers and populous residential areas. Blocks with higher population density, higher aging rate, more metro stations, more main roads, and more commercial point-of-interests (POIs) have a higher density of COVID-19 cases. These five explanatory variables explain 76% variance of self-reported cases using an OLS model. Commercial POIs have the strongest influence, which increase COVID-19 cases by 28% with one standard deviation increase. The GWR model performs better than OLS model with the adjusted R ² of 0.96. Spatial heterogeneities of coefficients in the GWR model show that influencing factors play different roles in diverse communities. We further discussed potential implications for the healthy city and urban planning for the sustainable development of cities.

An integrated importance-performance analysis and modified analytic hierarchy process approach to sustainable city assessment

Sustainable urban development has been a popular subject in urban studies and related disciplines. Owing to the challenges faced by cities worldwide to accommodate the growing urban populations, it is becoming ever more important for innovative research on sustainable urban development to be performed to help cities achieve sustainability. This study develops and tests an integrated approach to sustainable city assessment, which is a combination of importance-performance analysis (IPA) and modified analytic hierarchy process (AHP). Questionnaires designed following the IPA concept were distributed to residents of three cities. The importance scores from the collected data were factorized and the factors' relative scores were then calculated using a formula developed in this study to represent pairwise comparisons. The derived criteria weights were applied to the performance scores to evaluate the cities' relative overall sustainability performance. This approach replaces the AHP's 1-9 scale with the IPA's importance rating scale, which is a Likert scale, in the questionnaire. Based on the findings, implications and future research suggestions were provided.

Urban attributes and the spread of COVID-19: The effects of density, compliance and socio-political factors in Israel

Current debates identifying urban population density as a major catalyst for the spread of COVID-19, and the praise for de-densification and urban sprawl that they entail, may have dire environmental consequences. Juxtaposing competing theories about the urban antecedents of COVID-19, our key argument is that urban political attributes overshadow the effects of cities' spatial characteristics. This is true even when considering levels of compliance with movement restrictions and controlling for demographic and socio-economic conditions. Taking advantage of Israel as a living lab for studying COVID-19, we examine 271 localities during the first 3 months of the outbreak in Israel, a country where over 90% of the population is urban. Rather than density, we find social makeup and politics to have a critical effect. Cities with some types of political minority groups, but not others, exhibit higher infection rates. Compliance has a significant effect and density's influence on the spread of the disease is contingent on urban political attributes. We conclude with assessing how the relationship between the politics of cities and the spread of contagious diseases sheds new light on tensions between neo-Malthusian sentiments and concerns about urban sprawl and environmental degradation.

The municipal council, my neighbors and me: Social environmental influences in the city

This study seeks to examine the extent to which the level of municipal environmental management affects and complies with the behavioral norms of urban communities (city norms), and to what extent these affect environmental behavior at the individual level. We used a two-step, mixed-methods approach: a quantitative study of a representative sample of the urban sector (n = 1000) in Israel, followed by a qualitative in-depth interview process (n = 20). Municipal environmental management was found to be strongly correlated with city norms. Multiple regression analyses revealed that the residents' environmental behavior was strongly influenced solely by city norms (and not by the municipal council's conduct). However, our interviews revealed that residents explicitly attributed their pro- or anti-environmental behavior almost solely to the municipal council's conduct (and not to city norms). These relative contributions of municipal environmental management versus city norms on environmental behavior varied across environmental domains. In the Discussion section, we offer an explanation to the seemingly contradictory findings, and offer specific recommendations for several actions and initiatives that local authorities can adopt to promote pro-environmental behavior among its residents' and thus reduce the ecological footprint of the city as a whole.

Environmental exposure during travel: A research review and suggestions forward

Daily travel through the urban fabric exposes urban dwellers to a range of environmental conditions that may have an impact on their health and wellbeing. Knowledge about exposures during travel, their associations with travel behavior, and their social and health outcomes are still limited. In our review, we aim to explain how the current environmental exposure research addresses the interactions between human and environmental systems during travel through their spatial, temporal and contextual dimensions. Based on the 104 selected studies, we identify significant recent advances in addressing the spatiotemporal dynamics of exposure during travel. However, the conceptual and methodological framework for understanding the role of multiple environmental exposures in travel environments is still in an early phase, and the health and wellbeing impacts at individual or population level are not well known. Further research with greater geographical balance is needed to fill the gaps in the empirical evidence, and linking environmental exposures during travel with the causal health and wellbeing outcomes. These advancements can enable evidence-based urban and transport planning to take the next step in advancing urban livability.

Detailed municipal solid waste composition analysis for Nur-Sultan City, Kazakhstan with implications for sustainable waste management in Central Asia

A detailed characterization of municipal solid waste (MSW) beyond a standard compositional analysis may offer insights useful for improving waste management systems. The present paper contributes to the scarce literature in the field by presenting new data from a rapidly developing Central Asian city, the capital of Kazakhstan, Nur-Sultan. Three sampling campaigns (each 1 week long) have been conducted at the city landfill over a 1-year period (2018-2019), and a detailed characterization for selected waste components and sub-components has been performed. The major fractions of MSW were organics (46.3%), plastics (15.2%), paper (12.8%), and diapers (5.9%). The detailed composition analysis showed high LDPE (low-density polyethylene) content (5.5%) mostly comprised of plastic bags (4.5%), transparent glass (3.2%), pharmaceuticals (0.4%), and fine (i.e., < 12 mm) organic fraction content (29%). The MSW generation rate of Nur-Sultan was estimated as 1.47 kg capita^-1 day^-1 based on the field collection as well as literature data. Among sustainable waste management recommendations addressed for Nur-Sultan and applicable to other cities in Central Asia, composting is recommended due to high organics fraction in MSW and its great potential to reduce the landfilled waste volume and to help valorizing the waste.

Mechanistic insights into organic carbon-driven water blackening and odorization of urban rivers

With rapid global urbanization, massive anthropogenic inputs of organic matter and inorganic nutrients are resulting in severe pollution of urban rivers and consequently altering the structure and function of their aquatic microbial communities. In contrast to nutrient-induced eutrophication of freshwaters, water blackening and odorization of urban rivers, as well as their microbial communities, are poorly understood at a mechanistic level. Here, in a one-year field study on the taxonomic composition, predicted function and spatiotemporal dynamics of water and sediment microbial communities in seven black-odorous urban rivers in a megacity in southern China, combined with laboratory water-sediment column experiments, we pinpointed organic carbon as a key parameter driving the overgrowth of aquatic heterogeneous microorganisms. These microorganisms are major constituents of suspended black flocs that mediate methanogenic digestion of organic carbon and consequent water blackening and odorization. Source tracking analysis revealed a strikingly high contribution of sewage communities to black-odorous water microbial communities, in which emerging pathogens are enriched. Our results provide mechanistic insight into organic carbon-driven water blackening and odorization of urban rivers, which brings up current remediation strategies in questioning and sheds light on the future sustainable management of urban aquatic ecosystems.

Beyond 'trees are good': Disservices, management costs, and tradeoffs in urban forestry

The provision of ecosystem services is a prominent rationale for urban greening, and there is a prevailing mantra that 'trees are good'. However, understanding how urban trees contribute to sustainability must also consider disservices. In this perspective article, we discuss recent research on ecosystem disservices of urban trees, including infrastructure conflicts, health and safety impacts, aesthetic issues, and environmentally detrimental consequences, as well as management costs related to ecological disturbances and risk management. We also discuss tradeoffs regarding species selection and local conservation concerns, as well as the central role of human perception in the interpretation of ecosystem services and disservices, particularly the uncritical assertion that 'everybody loves trees'. Urban forestry decision-making that fails to account for disservices can have unintended negative consequences for communities. Further research is needed regarding life cycle assessments, stakeholder decision-making, return-on-investment, and framings of services and disservices in urban forestry.

Measuring urban food-energy-water nexus sustainability: Finding solutions for cities

A city is the place where food, energy, and water consumption happen. This consumption leads to challenges and has a strong impact on natural sources. Although researchers broadly agree on the importance of incorporating the concept of the food, energy, and water nexus into policy strategies and decision-making, the assessment system for how governance methods can improve the provision of these three essential services is relatively blank. To clarify the policy mechanisms and heterogeneity of sustainability issues related to the food, energy and water nexus at the city level, this study develops an indicator system to guide the implementations and optimize urban sustainability. A qualitative approach is employed to form the priority strategies in in four selected cities: Amsterdam, Eindhoven, Taipei, and Tainan. The results show that renewable energy plays an essential role in the food-energy-water nexus. In addition, we also observed that future work should focus on technological innovation. These observations imply that the unique combination of influence factors in food-energy-water sustainability offers a comprehensive outlook of the broad and complex challenges that a city faces due to resource limitations, which can help inform future governance practices. Finally, some policy recommendations are made for highlighting and the activities needed to work. The results of the present evaluation could be used as a tool to strengthen food-energy-water management in the future. They can guide managers to develop possible solutions that ensure resources are applied successfully according to the visions of multiple perspectives and help the relevant ministries to improve future consultation plans.

Reexamining the relationship between urbanization and pollutant emissions in China based on the STIRPAT model

Understanding the relationship between urbanization and pollutant emissions in China is of great significance to realizing sustainable development. Previous studies focused on the relationship between urbanization and air pollutants in China. However, the relationship between urbanization and industrial or domestic pollutants remains unclear. In this paper, we used the stochastic impacts by regression on population, affluence, and technology (STIRPAT) model to examine whether an environmental Kuznets curve (EKC) relationship exists between urbanization and pollutant emissions, including industrial wastewater, industrial SO₂, industrial soot (dust), and domestic garbage based on panel data for 277 prefecture-level cities in China from 2003 to 2015. We found that industrial soot (dust) emissions and domestic garbage increased by 83.0% and 43.5%, respectively, whereas industrial wastewater discharge and SO₂ emissions decreased by 7.4% and 10.5%, respectively. The identified inverted U-shaped relationship between the urbanization ratio (i.e., percentage of the population living in urban areas) and industrial pollutants supports the EKC hypothesis. However, the domestic garbage volume increased with increasing urbanization ratio. In the future, more attention should be paid to the prevention and control of domestic pollution. In addition, small and medium-sized cities should reduce pollutant emissions and determine effective ways to achieve sustainable development.

Compaction conditions affect the capacity of biochar-amended sand filters to treat road runoff

Amending roadside soil with adsorbents such as biochar can help remove pollutants from road runoff. To maintain soil stability, the roadside soil requires compaction. However, it is unknown how compaction conditions affect the capacity of biochar-augmented roadside biofilters to infiltrate stormwater and remove pollutants. This work examines the effect of compaction conditions on the release of biochar particles disintegrated during compaction, and the change in their capacity to infiltrate stormwater and remove E. coli. The net loss of biochar particles by mobilization with stormwater was insignificant compared to the biochar remained in the filters. The initial release of biochar particles in wet-compacted biochar columns was greater than that in dry-compacted biochar. The results revealed that compaction can affect the release of biochar particles in a series of three-step processes: generation of particles by disintegration of large biochar under compaction, diffusion of particles deposited near grain walls to bulk pore water, and transport and retention of particles in constricted pore paths based on pore water connectivity. Under similar conditions, compost columns released more particles than biochar columns, suggesting biochar is more stable than compost under compaction. E. coli removal in wet-compacted columns was greater than removal in dry-compacted columns, owing to greater pore path connectivity in wet-compacted columns. These results indicate that addition of moisture during compaction can increase contaminant removal, initial particle release, and infiltration capacity of biochar-augmented sand filters for road runoff treatment. The results would help develop design guidelines for roadside stormwater treatment systems that require compaction of filter media.

Relationship between pedestrian-level outdoor thermal comfort and building morphology in a high-density city

Urban compact buildings impose large frictional drag on boundary-layer air flow and create stagnant air within the building environment. It results in exacerbating the street-level outdoor thermal comfort (OTC). It is common to perform in-situ measurements of the OTC in different urban forms and to study their relationship. However, it is impossible to do so from a planning perspective because of the absence of physical planned urban forms. Our objective was to quantify the thermal environment and OTC in different planned complex urban forms by well-validated numerical models. We coupled a computational fluid dynamics (CFD) model to an OTC (Rayman) model to study the OTC. The κ-ω SST turbulent model was adopted for the CFD simulations, with accuracy of the turbulent model validated by wind tunnel measurements. The highest calculated air temperature within the street canyon of a planned bulky urban form could reach more than 5 °C higher than the surrounding environment. Within the tested urban forms, our coupled model predicted mean radiant temperature comparable with measurements in the literature. The model also produced sensible street-level physiologically equivalent temperatures (PETs) when comparing with those listed in the human thermal sensation categories. In the morning, the predicted PETs within all the urban forms were lower than that in open areas, which indicated that the shading of buildings effectively reduced the PET increase due to solar irradiance. At noon, increases in PETs by more than 10 °C relative to the morning situation indicated that when the buildings acted as heat sources after insolation absorption, increase in the air temperature at the street intersection and in the street canyon made an important contribution to the receiver PETs. The reduction in building lengths and increase in the low-level porosity were the most effective ways to reduce the heat stress at the pedestrian-level.

The growth mode of built-up land in floodplains and its impacts on flood vulnerability

Built-up land in floodplains (BLF) is a vital indicator of the socio-hydrological system, and its dynamics are key to understanding and managing flood risk. However, previous studies have neglected the impacts of BLF growth modes (e.g., patch sizes and expansion types) on flood vulnerability. This paper fills this gap by assessing the BLF's growth modes and revealing their divergent impacts on flood vulnerability using a case study in the Yangtze River Economic Belt (YREB), China. The results show that the BLF has nearly doubled in the YREB during 1990-2014. A considerable proportion (35.43%) of the BLF growth is scattered in small patches (≤1 km²), which have a much stronger correlation with flood occurrence than that of the other patch sizes. In terms of expansion types, the edge-expansion type dominates 57.52% of the BLF growth, followed by the leapfrogging and infilling expansions. Both the leapfrogging and the edge-expanding BLFs are significantly associated with flood occurrence, while the infilling type is not. The patch size and expansion type can thus influence the vulnerability of BLF patches, which is also supported by real-world cases. These findings enrich a general understanding of BLF growth and its impacts on flood vulnerability. The scientific community and policymakers should pay attention to not only the quantity of BLF growth, but also its spatial arrangement.

The determinants of urban sustainability in Chinese resource-based cities: A panel quantile regression approach

Improving energy efficiency and reducing environmental pollution emissions are two important ways to alleviate energy problems. Despite the progress in energy efficiency, the growth in energy demand still exceeds the efficiency improvements. This study adopts nonparametric methods to estimate the total factor energy efficiency (TFEE) of 105 resource-based cities covering the period 2010-2016 in China and analyzes the spatiotemporal characteristics of changes in energy efficiency. Furthermore, panel quantile regression is applied to analyze the multiple impacts of economic level, industrial structure, resource endowment, energy price, government intervention and degree of openness on energy efficiency. The main findings are as follows. (1) Each determinant has a different influence on TFEE at different levels; among them, the influence of the fuel and energy price index show an inverted U-shaped distribution as the quantile increases, and that of the GDP per capita shows a stronger heterogeneity than those of other factors. (2) Resource-based cities with lower efficiency are more sensitive to government intervention than are cities with higher efficiency. (3) A city's openness has a negative effect on TFEE, which partly supports the pollution haven hypothesis: the more foreign investment a resource-based city receives, the lower its energy and technology efficiency. Finally, some practical suggestions for the sustainable development of resource-based cities are discussed.

Multi actor multi criteria analysis (MAMCA) as a tool to build indicators and localize sustainable development goal 11 in Brazilian municipalities

The Sustainable Development Goals (SDGs) were adopted in 2015 to be a guideline to promote sustainable development through partnerships. Goal 11 was designed to improve the quality of life in cities however, confronted local governments with new challenges to delivery services and increase citizen participation. In this study, a conceptual framework was developed, and distinct indicators were analyzed to facilitate the implementation of SDG 11 in Brazilian municipalities. Two case studies were deployed based on the Multi-Actor Multi-Criteria Analysis (MAMCA) to guarantee stakeholder participation during the whole process. The results brought to light important challenges to urbanization at local levels. Also, the results suggest shifts in the ongoing model to evaluate the implementation of SDG 11 in Brazil. Governance, transparency and social participation were identified as critical issues to be addressed. Moreover, it will be necessary to adjust existing indicators and organize a consistent and frequent method to evaluate progress towards achieving SDG 11 targets at local levels. Integration of plans and policies related to climate change and disaster risk reduction represents another challenge to be faced by local governments. Finally, MAMCA can be a helpful tool to support local decision-makers to implement SDG 11 based on a multi-stakeholder view.

Transformative capacity and local action for urban sustainability

There is a consensus about the strategic importance of cities and urban areas for achieving a global transformation towards sustainability. While there is mounting interest in the types of qualities that increase the capacity of urban systems to attain deep transformations, empirical evidence about the extent to which existing institutional and material systems exhibit transformative capacity is lacking. This paper thereby seeks to determine the extent to which sustainability initiatives led by local governments and their partners reflect the various components that the literature claims can influence the emergence of transformative capacity as a systemic property of urban settings. Using an evaluative framework consisting of ten components of transformative capacity and associated indicators, the specific objective is to identify patterns in these initiatives regarding the presence of individual components of transformative capacity and their interrelations with other components. The analysis of 400 sustainability initiatives reveals thin evidence of transformative capacity. When detected, evidence of transformative capacity tended to emerge in relation to wider processes of institutional- and social-learning and initiatives that linked outcomes to a city-wide vision of planning and development. However, instances of such initiatives were rare. This widespread lack of evidence for transformative capacity raises concerns that this set of attributes normalised in the literature is in fact rarely found in sustainability action on the ground.

Building actor-centric transformative capacity through city-university partnerships

Cities worldwide are rising to the challenge of sustainable development, calling for large-scale and fast-paced transformations towards sustainability. Urban sustainability challenges are now being reframed as a lack of capacity of individuals and organizations to carry out such socio-technical transformations. This article expands on transformative capacity literature by elucidating the concept of actor-centric transformative capacity. It focuses on the unique role city-university partnerships (CUPs) can play in catalyzing and supporting effective urban sustainability transformations. Two case studies on CUPs in Portland, Oregon and Tempe, Arizona are used to identify determinants of actor-centric transformative capacity, their role in the transformative capacity of urban systems, and how they are built through CUPs. The article concludes with strategies for building effective CUPs capable of building actor-centric transformative capacity among university actors and city administrators.

Urban vegetation loss and ecosystem services: The influence on climate regulation and noise and air pollution

Ecosystem services are present everywhere, green vegetation coverage (or green areas) is one of the primary sources of ecosystem services considering urban areas sustainability and peoples urban life quality. Urban vegetation cover loss decreases the capacity of nature to provision ecosystem services; the loss of urban vegetation is also observed within the Amazon. This study aims at identifying urban vegetation loss and relate it to the provision of ecosystem services of reduction of air quality, reduction of air pollution, and climate regulation. Urban vegetation coverage loss was calculated using NDVI on LANDSAT 5 imagery over a 23-year period from 1986 to 2009. NDVI thresholds were arbitrarily selected, and complemented by in locus observation, to establish guidelines for quantitative (area) and qualitative (density) evolution of green cover, divided in six different categories, named as water, bare soil, poor vegetation, moderate vegetation, dense vegetation and very dense vegetation. Data on air pollution, noise pollution and temperature were outsourced from previous works. Measurement show a significant loss of very dense, dense and moderate vegetation coverage and an increase in poor vegetation and bare soil areas, in accordance to increase in air and noise pollution, and local temperature, and provides positive refashions between the loss of urban green coverage and decrease in ecosystem services.

Construction debris becomes growing concern of growing cities

How can growing cities be expanded in a sustainable way? Huge waste generation has become a major challenge in many growing cities, particularly in developing countries. China's annual C&D waste generation was and estimated 2.4 billion tonnes in the past decade, which is 15 times more than municipal solid waste generation. India has less C&D waste generation than China, yet still is as high as 530 million tons in 2013. However, only around 5% of C&D waste was reused in these countries and the rest largely ends up in dumping sites for disposal. As China and other developing countries continue to urbanize in the next decades, C&D waste management will continue to be a significant challenge for urban sustainability in terms of the environment, economics, and safety. We therefore critically reviewed the C&D waste generation, management, and challenges faced by the fast expanding cities in China and other developing countries. We also compared the current characteristics of key C&D waste systems in developing and developed countries. Recommendations for swift action are made for policy makers in growing cities.

Identifying conservation priorities and management strategies based on ecosystem services to improve urban sustainability in Harbin, China

Rapid urbanization and agricultural development has resulted in the degradation of ecosystems, while also negatively impacting ecosystem services (ES) and urban sustainability. Identifying conservation priorities for ES and applying reasonable management strategies have been found to be effective methods for mitigating this phenomenon. The purpose of this study is to propose a comprehensive framework for identifying ES conservation priorities and associated management strategies for these planning areas. First, we incorporated 10 ES indicators within a systematic conservation planning (SCP) methodology in order to identify ES conservation priorities with high irreplaceability values based on conservation target goals associated with the potential distribution of ES indicators. Next, we assessed the efficiency of the ES conservation priorities for meeting the designated conservation target goals. Finally, ES conservation priorities were clustered into groups using a K-means clustering analysis in an effort to identify the dominant ES per location before formulating management strategies. We effectively identified 12 ES priorities to best represent conservation target goals for the ES indicators. These 12 priorities had a total areal coverage of 13,364 km² representing 25.16% of the study area. The 12 priorities were further clustered into five significantly different groups (p-values between groups < 0.05), which helped to refine management strategies formulated to best enhance ES across the study area. The proposed method allows conservation and management plans to easily adapt to a wide variety of quantitative ES target goals within urban and agricultural areas, thereby preventing urban and agriculture sprawl and guiding sustainable urban development.

Exploring synergies between transit investment and dense redevelopment: a scenario analysis in a rapidly urbanizing landscape

Like many urban areas around the world, Durham and Orange counties in North Carolina, USA are experiencing population growth and sprawl that is putting stress on the transportation system. Light rail and denser transit-oriented development are being considered as possible solutions. However, local agencies and stakeholders are concerned the light rail may worsen housing affordability and have questioned whether investment in both light rail and dense redevelopment are necessary to achieve community goals. We developed an integrated system dynamics model to quantitatively explore the outcomes of these land use and transportation options across multiple societal dimensions. The model incorporates feedbacks among the land, transportation, economic, equity, and energy sectors. This paper uses the results of four model scenarios, run between 2000 and 2040, to address two main questions: (1) what role does redevelopment play in capturing the socioeconomic benefits of transit infrastructure investment? And (2) how do redevelopment and light-rail transit interact to affect housing and transportation affordability? We find that transit investment and dense redevelopment combine synergistically to better achieve the goals of the light-rail line, including economic development, mobility, and compact growth. However, housing affordability does worsen in the combined scenario, as transportation-cost savings are not sufficient to offset the rise in housing costs. We emphasize that model users may input their own assumptions to explore the dynamics of alternative scenarios. We demonstrate how spatially-aggregated systems models can complement traditional land use and transportation models in the regional planning process.

Assessment of urban sustainability efficiency based on general data envelopment analysis: a case study of two cities in western and eastern China

Sustainable urban development focuses on enhancing urban well-being, while also balancing the demands of urban social and economic development, natural resource consumption, and environmental pollution. This work used general data envelopment analysis to assess the urban sustainability efficiency (USE) and sustainability potential (SP) in Lanzhou and Xiamen, two cities that are characteristic of urban areas in western and eastern China. The assessment indicator system included important natural and urban welfare factors as input and output indices, respectively. The results showed that overall urban sustainability efficiency increased in Lanzhou and Xiamen from 1985 to 2010, but that the sustainability of natural resources clearly decreased. The urban sustainability efficiency of Xiamen was higher than that of Lanzhou, and the sustainability potential of Xiamen was lower than that of Lanzhou; this indicates that Xiamen performed better in terms of urban sustainable development. The urban sustainability efficiency in Xiamen has increased with increasing urban population, and the rate and scale of economic development have been higher than in Lanzhou. The assessment and analysis performed in this study show that cities with different natural resources and development characteristics have different forms, patterns, and trajectories of sustainable development.

Toward an Understanding of Citywide Urban Environmental Governance: An Examination of Stewardship Networks in Baltimore and Seattle

Efforts to create more sustainable cities are evident in the proliferation of sustainability policies in cities worldwide. It has become widely proposed that the success of these urban sustainability initiatives will require city agencies to partner with, and even cede authority to, organizations from other sectors and levels of government. Yet the resulting collaborative networks are often poorly understood, and the study of large whole networks has been a challenge for researchers. We believe that a better understanding of citywide environmental governance networks can inform evaluations of their effectiveness, thus contributing to improved environmental management. Through two citywide surveys in Baltimore and Seattle, we collected data on the attributes of environmental stewardship organizations and their network relationships. We applied missing data treatment approaches and conducted social network and comparative analyses to examine (a) the organizational composition of the network, and (b) how information and knowledge are shared throughout the network. Findings revealed similarities in the number of actors and their distribution across sectors, but considerable variation in the types and locations of environmental stewardship activities, and in the number and distribution of network ties in the networks of each city. We discuss the results and potential implications of network research for urban sustainability governance.

Climate change and fetal health: The impacts of exposure to extreme temperatures in New York City

BACKGROUND

Climate change is projected to increase the frequency, intensity, and duration of heat waves while reducing cold extremes, yet few studies have examined the relationship between temperature and fetal health.

OBJECTIVES

We estimate the impacts of extreme temperatures on birth weight and gestational age in Manhattan, a borough in New York City, and explore differences by socioeconomic status (SES).

METHODS

We combine average daily temperature from 1985 to 2010 with birth certificate data in Manhattan for the same time period. We then generate 33 downscaled climate model time series to project impacts on fetal health.

RESULTS

We find exposure to an extra day where average temperature <25 °F and >85 °F during pregnancy is associated with a 1.8 and 1.7 g (respectively) reduction in birth weight, but the impact varies by SES, particularly for extreme heat, where teen mothers seem most vulnerable. We find no meaningful, significant effect on gestational age. Using projections of temperature from these climate models, we project average net reductions in birth weight in the 2070-2099 period of 4.6g in the business-as-usual scenario.

CONCLUSIONS

Results suggest that increasing heat events from climate change could adversely impact birth weight and vary by SES.

Urban metabolism: Measuring the city's contribution to sustainable development

Urban metabolism refers to the assessment of the amount of resources produced and consumed by urban ecosystems. It has become an important tool to understand how the development of one city causes impacts to the local and regional environment and to support a more sustainable urban design and planning. Therefore, the purpose of this paper was to measure the changes in material and energy use occurred in the city of Curitiba (Brazil) between the years of 2000 and 2010. Results reveal better living conditions and socioeconomic improvements derived from higher resource throughput but without complete disregard to environmental issues. Food intake, water consumption and air emissions remained at similar levels; energy use, construction materials and recycled waste were increased. The paper helps illustrate why it seems more adequate to assess the contribution a city makes to sustainable development than to evaluate if one single city is sustainable or not.

Meeting critical challenges and striving for urban sustainability in China

China has experienced outstanding economic growth during the last three decades through urbanization. But at the same time, many ecological and social issues have been marginalized, leading to problems in public safety, health, and social equity. Such a pattern of development is unlikely to be sustainable. In this article, we examine these issues and the challenges that come with resolving them, and advocate a holistic and pragmatic approach to the research and practice of urban sustainability in China.