The study of urban metabolism and its applications to urban planning and design

From urban ecology to urban enquiry: How to build cumulative and context-sensitive understandings

This paper positions urban ecology as increasingly conversant with multiple perspectives and methods for understanding the functions and qualities of diverse cities and urban situations. Despite progress in the field, we need clear pathways for positioning, connecting and synthesising specific knowledge and to make it speak to more systemic questions about cities and the life within them. These pathways need to be able to make use of diverse sources of information to better account for the diverse relations between people, other species and the ecological, social, cultural, economic, technical and increasingly digital structures that they are embedded in. Grounded in a description of the systemic knowledge needed, we propose five complementary and often connected approaches for building cumulative systemic understandings, and a framework for connecting and combining different methods and evidence. The approaches and the framework help position urban ecology and other fields of study as entry points to further advance interdisciplinary synthesis and open up new fields of research.

Toward Heart-Healthy and Sustainable Cities: A Policy Statement From the American Heart Association

Nearly 56% of the global population lives in cities, with this number expected to increase to 6.6 billion or >70% of the world's population by 2050. Given that cardiometabolic diseases are the leading causes of morbidity and mortality in people living in urban areas, transforming cities and urban provisioning systems (or urban systems) toward health, equity, and economic productivity can enable the dual attainment of climate and health goals. Seven urban provisioning systems that provide food, energy, mobility-connectivity, housing, green infrastructure, water management, and waste management lie at the core of human health, well-being, and sustainability. These provisioning systems transcend city boundaries (eg, demand for food, water, or energy is met by transboundary supply); thus, transforming the entire system is a larger construct than local urban environments. Poorly designed urban provisioning systems are starkly evident worldwide, resulting in unprecedented exposures to adverse cardiometabolic risk factors, including limited physical activity, lack of access to heart-healthy diets, and reduced access to greenery and beneficial social interactions. Transforming urban systems with a cardiometabolic health-first approach could be accomplished through integrated spatial planning, along with addressing current gaps in key urban provisioning systems. Such an approach will help mitigate undesirable environmental exposures and improve cardiovascular and metabolic health while improving planetary health. The purposes of this American Heart Association policy statement are to present a conceptual framework, summarize the evidence base, and outline policy principles for transforming key urban provisioning systems to heart-health and sustainability outcomes.

Mass-Balance-Consistent Geological Stock Accounting: A New Approach toward Sustainable Management of Mineral Resources

Global resource extraction raises concerns about environmental pressures and the security of mineral supply. Strategies to address these concerns depend on robust information on natural resource endowments, and on suitable methods to monitor and model their changes over time. However, current mineral resources and reserves reporting and accounting workflows are poorly suited for addressing mineral depletion or answering questions about the long-term sustainable supply. Our integrative review finds that the lack of a robust theoretical concept and framework for mass-balance (MB)-consistent geological stock accounting hinders systematic industry-government data integration, resource governance, and strategy development. We evaluate the existing literature on geological stock accounting, identify shortcomings of current monitoring of mine production, and outline a conceptual framework for MB-consistent system integration based on material flow analysis (MFA). Our synthesis shows that recent developments in Earth observation, geoinformation management, and sustainability reporting act as catalysts that make MB-consistent geological stock accounting increasingly feasible. We propose first steps for its implementation and anticipate that our perspective as "resource realists" will facilitate the integration of geological and anthropogenic material systems, help secure future mineral supply, and support the global sustainability transition.

Source identification and health risk assessment of heavy metals with mineralogy: the case of soils from a Chinese industrial and mining city

Understanding the precise sources of heavy metals (HMs) in soil and the contribution of these sources to health risks has positive effects in terms of risk management. This study focused on the HMs in the soil of five land uses in an industrial and mining city. The sources of HMs in soils were identified, and the soil mineralogical characteristics and health risks of HMs were discussed. The results showed that the HMs (Cu, Zn, Ni, Cd, Pb) found in the soil of the five land uses were affected by human activities. For example, the Cu in grassland, gobi beach, woodland, green belt, and farmland is 22.3, 3.5, 22.5, 16.7, and 21.3 times higher than the soil background values in Gansu Province, respectively. The Positive Matrix Factorization model (PMF) results revealed that traffic emissions and industrial and agricultural activities were the primary sources of HMs in the soil, with industrial sources accounting for the largest share at 55.79%. Furthermore, various characteristics proved that the studied HMs were closely related to smelting products. Concentration-oriented health risk assessments showed that HMs in the different soil types held non-carcinogenic and carcinogenic risks for children and adults. Contamination source-oriented health risk assessments of children and adults found that industrial activities controlled non-carcinogenic and carcinogenic risks. This study highlighted the critical effects of smelting on urban soil and the contribution of pollution sources to health risks. Furthermore, this work is significant in respect of the risk control of HMs in urban soils.

Exploring the Intertwined Nexus between Globalization, Energy Usage, Economic Complexity, and Environmental Quality in Emerging Asian Economies: A Pathway Towards a Greener Future

The study aims to examine the relationship between carbon emissions and ecological footprints with economic complexity, core pollution indicators, urbanization, globalization, and renewable and non-renewable energy consumption in eight emerging Asian economies from 1971 to 2020. A panel data framework that considers cross-sectional dependence and heterogeneity was used for analysis. The Pedroni and Johnsen Fisher cointegration showed that carbon emission, ecological footprint, renewable and non-renewable energy consumption, economic complexity, globalization, and urbanization confirmed the presence of cointegration. Moreover, fully modified ordinary least squares (FMOLS) and dynamic ordinary least squares (DLOS) indicated that globalization, non-renewable energy consumption, and economic complexity increase emission and ecological footprint in the long run, whereas renewable energy generated through biomass, solar, and wind decreases environmental degradation. Furthermore, urbanization also negatively affects the environment. From a policy perspective, policymakers in these countries may manage their natural resources efficiently by escalating the share of renewables in total energy production, offering tax holidays, incentives and encouraging companies to install clean energy plant, and providing support to research and development-oriented companies to engage in research activities to reduce the cost of production of renewable energy.

Scenario analysis of phosphorus flow in food production and consumption system in the Mwanza region, Tanzania

Since the mineral, phosphorus (P), has dual properties of being limited resources for use, and being a pollutant for studying sustainable management of anthropogenic P flows in wetlands and soils, currently P receives the highest interests among researchers around the world. This study has successfully mapped P flows for a reference year (2017) and a future year (2030) using different scenarios of food production and consumption system (hereafter 'system') in the Mwanza region (Tanzania). The results showed that the total P input and output for 2017 alone were 9770 t and 7989 t, respectively. However, as high as 1781 tP accumulated in the system and the potentially recyclable P found, is yet to be recovered due to economic reasons and the lack of market. The main anthropogenic P input to the system occurred via imported feed, fertilizer, and crop food, accounting for about 99.72 % of the total input flow. The output was comprised of animal products exported with 3428 tP, and various P-contained wastes which were lost to water bodies with 4561tP. Analysis of the 2030 scenario showed that setting P management objectives from different perspectives such as the total P budget balance, potential recyclable P, and P emission, can help develop differentially preferred management strategies and measures in the Mwanza region. The combination of diet change, precision feeding, and integrated waste management practices presents the best prospects for decreasing P budget and losses, and the amount of P that can be potentially recovered from the system. We propose a package of integrated P management measures for the Mwanza region. Given the similarity of regional socio-economic development background around the Lake Victoria basin, the model can be used to guide the study of anthropogenic P flow analysis in other areas along the shore of Lake Victoria (Africa).

Superlinear urban scaling by functional organization: A metabolic interpretation of sectoral water consumption

Prevailing view asserts that the disproportionately greater productivities of larger cities, or superlinear urban scaling, are the result of human interactions channeled by urban networks. But this view was established by considering the spatial organization of urban infrastructure and social networks-the urban "arteries" effects-but neglecting the functional organization of urban production and consumption entities-the urban "organs" effects. Here, adopting a metabolic view and using water consumption as a proxy for metabolism, we empirically quantify the scaling of entity number, size, and metabolic rate for the functionally specific urban residential, commercial, public or institutional, and industrial sectors. Sectoral urban metabolic scaling is highlighted by a disproportionate coordination between residential and enterprise metabolic rates, attributable to the functional mechanisms of mutualism, specialization, and entity size effect. The resultant whole-city metabolic scaling exhibits a constant superlinear exponent for water-abundant regions in numerical agreement with superlinear urban productivity, with varying exponent deviations for water-deficient regions explainable as adaptations to climate-driven resource constraints. These results present a functional organizational, non-social-network explanation of superlinear urban scaling.

Leverage of resource efficiency over environmental emissions: Case of a megacity in China

Material metabolism in a Chinese megacity, Shanghai, was investigated with an integrated approach. Production-based raw material input, city-wide waste output and carbon emissions were compiled for the period 1995-2020, by computing hundreds of products and by-products. Decoupling of these resource and environmental flows from economic development was assessed, and the socio-economic and technical drivers were decomposed. The research demonstrated a hypothesis that flows of primary resources, waste, and carbon emissions displayed a certain level of synchronicity in the past decades. An order effect was seen with waste indicators usually performing better than carbon indicators, and carbon indicators are better than resource indicators in terms of material/environmental intensity and decoupling. There might be a resource leverage leading to the synchronicity of environmental emissions. Improvement in resource efficiency was decomposed as the most significant driver to urban metabolism, bringing about >33 % of resource reduction, 32 % of carbon mitigation, and 30 % of waste diminution from the 2010 values. A greater extent in emission reduction than resource use was attributed to the decrease of fossil fuels share in total resource use and carbon intensity per energy consumption. Continuous increase in post-use waste flows caused a rebound of waste indicators in the recent five-year period (2016-2020) and broke up the synchronicity. This potentially foresees the shift of material metabolism from production to consumption side in major cities in China and calls for reforms of environmental policies.

How Can Material Stock Studies Assist the Implementation of the Circular Economy in Cities?

City and regional planners have recently started exploring a circular approach to urban development. Meanwhile, industrial ecologists have been designing and refining methodologies to quantify and locate material flows and stocks within systems. This Perspective explores to which extent material stock studies can contribute to urban circularity, focusing on the built environment. We conducted a critical literature review of material stock studies that claim they contribute to circular cities. We classified each article according to a matrix we developed leveraging existing circular built environment frameworks of urban planning, architecture, and civil engineering and included the terminology of material stock studies. We found that, out of 271 studies, only 132 provided information that could be relevant to the implementation of circular cities, albeit to vastly different degrees of effectiveness. Of these 132, only 26 reported their results in a spatially explicit manner, which is fundamental to the effective actuation of circular city strategies. We argue that future research should strive to provide spatial data, avoid being siloed, and increase engagement with other sociopolitical fields to address the different needs of the relevant stakeholders for urban circularity.

Exploration of the Relationship between Planning Research Investment and National Macro Development—An Empirical Study Based on Papers since 1950

The world is accelerating globalization and urbanization; thus, planning plays an irreplaceable role in the macro development, especially in sustainable development. Planning research is important in turning theories of planning into urban practices. This research based on the theory that planning research is crucial, as it represents that planning-related activities improve processes in urbanization. However, the current understanding of the importance of planning research is limited. There is no research on the interaction between planning research and macro national development to support the importance of planning or its research. This study uses 750,000 articles on urban planning fields from WoS from 1950 to the present. Firstly, the study concludes the investment pattern changes of the global planning research. Over the past 70 years, the total number and diversity of countries engaged in planning research have grown rapidly, and developing countries have gradually integrated into the mainstream research community and become the main contributors. Secondly, the investment intensity and characteristics of planning research are consistent with the speed and characteristics of urbanization, which proves that to some extent, the demand of urbanization development drives the investment of planning research. Then, according to the different characteristics of planning research investment in different countries, this paper summarizes the main investment characteristics of major countries, analyzes the development rule behind the investment characteristics, and predicts the interaction with the international political and economic pattern. By analyzing the relationship between planning research intensity and urbanization, it is found that the investment intensity of planning research has a time rule with urbanization and has different interactions in different stages of urbanization development. It was found that the intensity of planning research was strongly correlated with HDI, and the amount of research was crucial.

Assessing the asymmetric impact of physical infrastructure and trade openness on ecological footprint: An empirical evidence from Pakistan

This study analyzed the asymmetric impact of the physical infrastructure and trade openness on Pakistan’s ecological footprint over the period 1970–2019 using the non-linear autoregressive distributed lag model. The study results posit that positive and negative shocks to physical infrastructure increase and decrease the ecological footprint asymmetrically in the short-run and symmetrically in the long-run. Likewise, the positive and negative shocks to trade openness increase and decrease the ecological footprint asymmetrically, both in the short and in the long run. Furthermore, urbanization also positively and significantly increases Pakistan’s ecological footprint in the short and long run. Moreover, a 1% increase in physical infrastructure increases the ecological footprint by 0.32%, while a 1% decrease in physical infrastructure decreases the ecological footprint by 0.33% in the long run. Similarly, a 1% increase in trade openness causes a 0.09% increase in the ecological footprint in the long term, while a 1% reduction in trade openness causes a 0.61% reduction in the ecological footprint. The results also conclude that urbanization is a major determinant of Pakistan’s long-term ecological footprint. Thus, a 1% increase in urbanization causes a 1.31% increase in the ecological footprint in the long run. Finally, this study recommends that policies regarding physical infrastructure be formulated keeping in view its environmental impact. In addition, strict environmental policies should be implemented to reduce the environmental degradation effect of trade openness.

Exploring Potential Ways to Reduce the Carbon Emission Gap in an Urban Metabolic System: A Network Perspective

To meet the global need for carbon neutrality, we must first understand the role of urban carbon metabolism. In this study, we developed a land-energy-carbon framework to model the spatial and temporal variation of carbon flows in Beijing from 1990 to 2018. Based on the changes in carbon sequestration and energy consumption, we used ecological network analysis to identify the critical paths for achieving carbon neutrality during land-use changes, thereby revealing possible decarbonization pathways to achieve carbon neutrality. By using GIS software, changes in the center of gravity for carbon flows were visualized in each period, and future urban construction scenarios were explored based on land-use policy. We found that the direct carbon emission peaked in 2010, mostly due to a growing area of transportation and industrial land. Total integrated flows through the network decreased at an average annual rate of 3.8%, and the change from cultivated land to the socioeconomic sectors and the paths between each socioeconomic component accounted for 29.5 and 31.7% of the integrated flows during the study period. The socioeconomic sectors as key nodes in the network should focus both on their scale expansion and on using cleaner energy to reduce carbon emissions. The center of gravity gradually moved southward, indicating that the new emission centers should seek a greener mixture of land use. Reducing carbon emission will strongly relied on transforming Beijing's energy consumption structure and increasing green areas to improve carbon sinks. Our results provide insights into carbon flow paths that must be modified by implementing land-use policies to reduce carbon emission and produce a more sustainable urban metabolism.

Evaluation of urban metabolism assessment methods through SWOT analysis and analytical hierocracy process

The interconnection of urbanization trends and environmental pressures, are due to the rising demand for resource consumption, waste production and greenhouses gas emissions. Taking into consideration the massive reduction of natural resources, the deprivation of the life quality and the climate change, the scientific community indicates the necessity to emphasis and understand the relationship between cities and the environment as a dynamic concept. Consequently, cities are facing the challenge to implement alternative strategies towards more sustainable management of urban resources. This research aims to shed light on the concept of urban metabolism, the methods that are been used to gauge urban metabolism (i.e Emergy Analysis, Material Flow Analysis, Ecological Footprint etc.), as well as the assessment of the proposed methodologies through SWOT analysis and Analytical Hierocracy Process, considering multi-criteria analysis and how those reflect to Circular Economy and European Green Deal Strategy. The results showed that, the existing methodologies needs refreshment to cover the needs for the cities of tomorrow and a new hybrid approach which will include new set of Key Performed Indicators is essential. Furthermore, the results could serve as a beneficial reference point for policy makers, consultants, rural developers as the new hybrid approach can be used to measure and assess the level of metabolism in one area in order to prevent future expansion.

Industrial metabolism and territorial development of the Maurienne Valley (France)

The globalisation of exchanges has resulted in excessive growth of material and immaterial flows. The disconnection among the supply, production, decision-making and consumption sites generates new spatial interdependencies. It determines local socio-economic dynamics and affects ecosystems. In this context, the question arises if territorial capability-"localized collective capacity to serve territorial development"-influences, from local level, these globalised flows systems. By combining territorial economic principles and territorial ecology approaches, we study the industrial metabolism of the Maurienne valley in France. The Maurienne case shows how territorial characteristics contribute to the economic resilience in rural areas. The calculation of wealth flows provides information on the local economic base, the weight of industry and its social impact. The analysis of physical flows reveals the materiality of this industry and the dependence on external resources and international companies. It highlights the various pressures and risks on the environment. To deal with these constraints, companies rely on relational and geographic proximities with local subcontractors. These relationships determine both the proper functioning of the local industrial system and the territorial capability to maintain and transform industrial activities. Most rural European territories experience the same industrial issues and environmental challenges. Therefore, this study offers new research perspectives to better understand and promote ecological transition in old and often rural industrial areas.

Assessing Urban Metabolism through MSW Carbon Footprint and Conceptualizing Municipal-Industrial Symbiosis—The Case of Zaragoza City, Spain

This paper proposes a holistic vision of the urban metabolism (UM), viewing the city as a subsystem within an industrial ecosystem (IE) in which municipal-industrial symbiosis is essential to achieve sustainability goals. For this purpose, the metabolism of a large Spanish city, Zaragoza, was studied by analyzing the main fractions of its MSW. A methodology based on carbon footprint (CF) was developed to analyze the environmental impact—in terms of CO2—of the influence of households’ behavior, the City Council’s strategies, and the main MSW fractions. Zaragoza’s IE represents a footprint of 931,250 CO2 tons for the fractions studied, of which 438,000 CO2 tons are due to organic fraction, 180,371 to plastics and 154,607 to paper and cardboard, which are the three most significant contributors. If households selectively separated 100% of their waste, the footprint would drop to 648,660 tons of CO2. Furthermore, monetary savings were quantified through the CO2 emissions price. The proposed methodology accounts for the CF of the whole IE, not just the city. Moreover, it enables the creation of Sankey diagrams to visualize the distribution of emissions of each subsystem, highlighting the importance of cooperation between the city and its recycling industries to reduce its CF.

Smart District and Circular Economy: The Role of ICT Solutions in Promoting Circular Cities

Cities will have a decisive role in reducing the consumption of resources and greenhouse gas emissions by 2050. Various experiences of urban regeneration have exploited Information and Communication Technology (ICT) potentialities to optimize the management of complex systems and to encourage sustainable development models. This paper investigates the role of ICT technologies in favouring emerging design for Circular Economy (CE) in the urban context. The paper starts by defining the theoretical background and subsequently presents the goal and methodology of investigation. Through a scoping review, the authors identify case studies and analyse them within the Ellen MacArthur Foundation classification framework that splits the urban context into three urban systems: buildings, mobility and products. The research focuses on nine case studies where the ICT solutions were able to promote the principles of CE. The results show, on the one hand, how data management appears to be a central issue in the optimization of urban processes and, on the other hand, how the district scale is the most appropriate to test innovative solutions. This paper identifies physical and virtual infrastructures, stakeholders and tools for user engagement as key elements for the pursuit of CE adoption in the urban context.

Macro Sustainability across Countries: Key Sector Environmentally Extended Input-Output Analysis

When formulating economic development strategies, the environment and society must be considered to preserve well-being. This paper proposes a comparative sustainability assessment method using environmentally extended input-output analysis and multi-criteria decision aid. Using symmetric input-output tables and sectoral CO2 emissions and employment data for six countries, linkage coefficients are calculated for 163 sectors in each country. Multi-criteria decision aid tool, ELECTRE III, is used to derive outranking relationships among each country’s sectors using these coefficients as criteria, resulting in a hierarchy of sectors ordered by sustainability. Sectors that frequently appear at the top of the six hierarchies included education, health care, construction, and financial intermediation. China’s results differ significantly because of its concentration of economic activity on the primary/secondary sectors. The results can enable identification of key intervention pathways along which sustainable development could be stimulated. Country-specific recommendations and reflections on economic and sustainability policy initiatives are discussed.

Climate Change, Adaptation Planning and Institutional Integration: A Literature Review and Framework

The scale and scope of climate change has triggered widespread acknowledgement of the need to adapt to it. Out of recent work attempting to understand, define, and contribute to the family of concepts related to adaptation efforts, considerable contributions and research have emerged. Yet, the field of climate adaptation constantly grapples with complex ideas whose relational interplay is not always clear. Similarly, understanding how applied climate change adaptation efforts unfold through planning processes that are embedded in broader institutional settings can be difficult to apprehend. We present a review of important theory, themes, and terms evident in the literature of spatial planning and climate change adaptation to integrate them and synthesize a conceptual framework illustrating their dynamic interplay. This leads to consideration of how institutions, urban governance, and the practice of planning are involved, and evolving, in shaping climate adaptation efforts. While examining the practice of adaptation planning is useful in framing how core climate change concepts are related, the role of institutional processes in shaping and defining these concepts—and adaptation planning itself—remains complex. Our framework presents a useful tool for approaching and improving an understanding of the interactive relationships of central climate change adaptation concepts, with implications for future work focused on change within the domains of planning and institutions addressing challenges in the climate change era.

A more sustainable urban future calls for action: the city of Lahti as European Green Capital 2021

In 2020, a small urban center from southern Finland, the City of Lahti, was awarded the 2021 European Green Capital, which recognizes and rewards local efforts that seek to improve the urban environment, together with its economy and the quality of life for its inhabitants, further posing ambitious goals for ecological improvement. In this commentary, we describe some of the key elements that made Lahti the 2021 European Green Capital, as well as some of the future plans for the city. We also highlight the importance of research-based knowledge as the foundation for achieving better outcomes in urban decision making.

Seeking Circularity: Circular Urban Metabolism in the Context of Industrial Symbiosis

Cities are leading in the implementation of circular economy (CE) principles and sustainable development due to the concentration of knowledge, resources and technology while remaining the highest consumers and producers of resources. CE, urban metabolism (UM) and industrial symbiosis (IS) offer a new more holistic approach based on material and energy flow analysis and materials recovery from waste by creating IS networks to support a new circular urban system (CUM) which contrast to the traditional linear extract-produce-use-dispose model of economic systems. In this paper, we present the concepts of CE, IS and CUM and how the new framework could improve cities transition to sustainability and CE, with detailed CE and IS indicators analysis. We introduce the relations between IS, CE and UM concepts, how they can be used and monitored in the CUM framework. CUM can help unite urban planners, the city’s governance and the business sector to promote collaboration across the city to improve future sustainability and circularity by closing loops.

Indoor Air Quality Improvement Using Nature-Based Solutions: Design Proposals to Greener Cities

Low indoor air quality is an increasingly important problem due to the spread of urbanization. Because people spend most of their time inside, poor indoor air quality causes serious human health issues, resulting in significant economic losses. In this work, the current state of affairs is presented and analyzed, focusing on the current problems and the available solutions to improve the quality of indoor air, and the use of nature-based solutions. These involve the cultivation of microalgae in closed photobioreactors. In these systems, photosynthetic organisms can capture CO₂ and other pollutants generated in indoor environments, which they use to grow and develop biomass. Several possible layouts for the implementation of microalgae-based indoor air cleaning systems are presented, taking into account the systems that are currently available at a commercial scale. A critical analysis of the microalgae indoor purification systems is presented, highlighting their advantages and disadvantages, and suggesting potential improvements and future lines of research and development in the area.

Open and Consistent Geospatial Data on Population Density, Built-Up and Settlements to Analyse Human Presence, Societal Impact and Sustainability: A Review of GHSL Applications

This review analyses peer-reviewed scientific publications and policy documents that use built-up density, population density and settlement typology spatial grids from the Global Human Settlement Layer (GHSL) project to quantify human presence and processes for sustainability. Such open and free grids provide detailed time series spanning 1975–2015 developed with consistent approaches. Improving our knowledge of cities and settlements by measuring their size extent, as well as the societal processes occurring within settlements, is key to understanding their impact on the local, regional and global environment for addressing global sustainability and the integrity of planet Earth. The reviewed papers are grouped around five main topics: Quantifying human presence; assessing settlement growth over time; estimating societal impact, assessing natural hazard risk and impact, and generating indicators for international framework agreements and policy documents. This review calls for continuing to refine and expand the work on societal variables that, when combined with essential variables including those for climate, biodiversity and ocean, can improve our understanding of the societal impact on the biosphere and help to monitor progress towards local, regional and planetary sustainability.

Digital Technologies for Urban Metabolism Efficiency: Lessons from Urban Agenda Partnership on Circular Economy

Digital technologies engaged in urban metabolism for efficiency provide policymakers, urban managers, and planners with useful instruments to collect, monitor, analyze, and evaluate the circularity of environmental, social, and economic resources to improve their effectiveness and quality. At present, the digital technology-based approach is strategic for circular cities engaged in the development of smart and sustainable actions in the fields of mobility, energy, environment, waste, telecommunications, and security. Through the ‘Circular Resource Efficiency Management Framework’ developed by the European Commission, this paper generates insights into the digitalization practices of the circularity of urban metabolism by analyzing the initiatives implemented by the municipalities of Kaunas, Flanders region, Porto, Prato, The Hague, and Oslo, which constitute the Partnership on Circular Economy (PCE) of the Urban Agenda of the European Union. The results of the analysis provide a wide range of practices such as real-time monitoring stations for water and energy consumption, digital cameras for controlling vehicle flows, web platforms for sharing goods and services, and tracking sensors for public transport, which aim to optimize the efficiency of the circularity of urban metabolic flows. This study increases the understanding and awareness of digital technologies in this paradigm shift.

Economic sensitivity analysis of dual perspectives induced by energy scarcity for energy-dependent region

Rapid industrialization leads to potential energy scarcity. The formulation of energy intervention can alleviate the economic losses caused by insufficient energy inputs in advance. In this study, the energy dependency and sensitivity quantification model (EDSQ) is firstly developed to evaluate the impacts of insufficient energy support on economic development under network-based perspective and sector-based perspective. A special case study for the Province of Shanxi, China, is conducted to illustrate the potential benefits of its use in the formulation of energy intervention for energy-dependent regions. Seven energy groups are explored to gain more insights into the impacts of specific energy groups on energy metabolism and the complicated interactions among sectors. It is found that the energy metabolism of Shanxi is under an unhealthy state. The internal flows are dominated by exploitation and competitive relationships, which is not conducive to effective energy metabolism. The hierarchy analysis indicates that the pulling force is hardly affected by the classified energy groups but the driving force is sensitive, which further reveals that the producers can choose different energy sources according to their production structure. Faced with potential energy scarcity, the shortage of coal may bring considerable economic losses. The energy intervention should be formulated for the sectors that are less dependent on energy. However, it is not recommended to curb energy use in the petroleum, coking, nuclear fuel processing and coal mining sectors, because their sectoral losses can impose significant losses to the entire network. Thus, the scientific results of this study can provide academic support for quantifying the impact of potential energy scarcity, and guide the formulation of energy intervention to achieve sustainable development for energy-dependent regions.

Development of a factorial water policy simulation approach from production and consumption perspectives

Industrial water-management policies are prevalent around the world to alleviate global water scarcity. It is indispensable to simulate the effects of different water-management policies on various industries in the socioeconomic system to explore the most effective water consumption reduction pathways. In this study, a factorial water policy simulation model is developed to investigate the composite effects of multidimensional interactive water-management policies from both production and consumption perspectives. Structural path analysis and factorial analysis are introduced simultaneously to help support policy formulation according to local reality and further examine the impacts of the main factors and their interactions respectively. The developed model has been applied to the Municipality of Chongqing, China to demonstrate the applicability and superiority of the factorial water policy simulation model. It was found that the impacts of industrial technology upgrade policies on different industries vary significantly. The consumption-orientation policies have a similar performance on direct water consumption reductions. In the Municipality of Chongqing, industrial technology upgrade policies applied to the primary industry will generate larger reductions of water consumption (i.e., 10.1 units reduction of total water consumption) in the system since the primary industry can influence other industries through intermediate utilization. The contribution of interactions for the reductions of direct water consumption was 10.38%, where policies implemented on the primary industry and construction industry have the most significant interaction. In addition, the industry of production and supply of water is closely related to most of the industries since its technical improved can reduce the indirect water consumption of the majority of industries. The results provide bases for supporting the Municipality's efforts in formulating desired water-management policies.

Urban strategies evaluation for waste management in coastal areas in the framework of area metabolism

Europe is considered one of the most attractive and safe prevalent tourist destinations in the entire world. Approximately half (47.4%) of European tourist visits occurred in coastal regions, defined "on the basis of and consist of local administrative units or municipalities that border the sea, or have at least half of their total surface area within a distance of 10 km from the sea." Destinations such as Malta, Greece, Cyprus, Spain and Croatia presented with an increased level of tourist accommodation establishments, as well as, the overall flow of tourism in the European Union is mostly concentrated on Mediterranean coastal regions (as nine out 10 tourists, in 2015, spent their holidays at coastal areas). This paper, is dealing with the assessment of a tourist area and how the concept of urban metabolism has been affected by touristic activities. Moreover, this research using several key performance indicators such as waste compositional analysis, the clean coast index, the accumulation rate, and accumulation index, etc., tries to measure the level of environmental performance, and furthermore, to assess the existing infrastructures and the waste management plan, that are being implemented. The results are very useful, for any policy-maker, as well as competent authorities and/or tourist organizations which are dealing with tourist activities and aim to propose or re-schedule any waste strategy targeting the goals of United Nations Sustainable Development Goals, European Green Deal, and the new circular economy strategy.

Transition to Smart and Regenerative Urban Places (SRUP): Contributions to a New Conceptual Framework

Modern urbanism is called to face current challenges ranging from intensive demographic growth, economic and social stagnation to resources salvation and climate changes. Under the broader scope of sustainability, we argue that the transition to a holistic perspective of smart and regenerative planning and design is the way to face and yet to prevent these urban challenges. In doing so, we adopt systematic thinking to study the complexity of urban metabolisms at an urban place scale, emphasizing the ongoing coevolution of social-cultural-technological and ecological processes. Focusing on urban places, we give a city or region the sense of a place of stability, security, cultural and social interactions, and a sense of uniqueness. We plan and design innovative urban places that improve the environment and the quality of urban life, able to adapt and mitigate climate changes and natural hazards, leverage community spirit, and power a green-based economy. Designing the conceptual framework of smart and regenerative urban places we contribute to the field of modern urban studies helping practitioners, policymakers, and decision-makers to vision and adopt more environmental-friendly policies and actions using a user-centered approach.

Sustainability accounting of neighborhood metabolism and its applications for urban renewal based on emergy analysis and SBM-DEA

Rapid urbanization exacerbates urban metabolic activities associated with irreversible environmental degradation. Evaluating urban metabolic performance is an effective method to meet targets for sustainable development in contemporary urban areas. Neighborhoods, which are regarded as the basic parts of cities, can detail the metabolic structure and interactions from a bottom-up perspective. In consequence, this study proposed an eco-efficiency model which combined emergy synthesis and slack-based measure data envelopment analysis. A case study with questionnaire and statistical data for eight communities in Chongqing, China was used to shed a light on the properties of emergy metabolic flows and eco-efficiency. The results showed that the study communities heavily depended on external resources. Intense communal activities within relatively small geographic areas caused immediate surroundings to suffer from enhanced environmental pressures. Eco-efficiency performances were mostly invalid, and a significant heterogeneity existed among communities. Enhancing the performance of renewable and non-renewable resources whilst also reducing the production of wastes was essential to improve the overall eco-efficiency of local communities. To assist with this, a neighbor-level sustainable renewal framework was proposed which took account of metabolic flows and communal renewal operations. The findings of this study can provide a paradigmatic example for urban renewal projects elsewhere that embed metabolic performance in neighborhood redevelopment.

Empirical Study of Urban Development Evaluation Indicators Based on the Urban Metabolism Concept

Sustainable development is the concept of coordinating people and the environment and achieves contemporary development without compromising the interests of the next generation. It can also be thought of as not exceeding the biosphere’s carrying capacity. Urban metabolism emphasizes resource recycling and use to achieve balance between resource input and product output in urban areas. However, the scale of cities has expanded rapidly in recent years along with resource and energy demands. Waste and pollution also cause major threats to the environment and ecology. Given increasingly serious environmental problems, the original linear metabolism must be converted into a cyclical one to ensure urban sustainability. From the policy implementation report of Taipei City, this study used the fuzzy Delphi method to develop evaluation factors and integrated this with the analytic network process decision-making tool to determine the priority weights of each policy and evaluate development strategies for urban development based on the metabolism concept. The study results reveal that natural environmental sustainability and sustainable energy strategies were prioritized plans for evaluating urban development with the metabolism concept, and the results can be used as a reference for future urban development strategies.

Implications of Low Carbon City Sustainability Strategies for 2050

Cities and urban areas are critical nodes of societal resource flows, responsible for both global and local sustainability implications. They are complex systems and understanding the implications of potential actions by cities is critical for progress towards sustainability. In this paper the future implications of sustainability strategies are assessed for 10 European cities by comparing two scenarios for 2050: a business-as-usual (BAU) and a post-carbon/sustainability scenario (PC2050) (generated by city stakeholders). The effects of the scenarios are assessed using a mixed methodology: a semi-quantitative sustainability indicator analysis, energy and greenhouse gas (GHG) emissions (both production-based and consumption-based accounting (PBA and CBA)), land-use spatial modelling, and cost–benefit analysis. The paper highlights the clear benefits of PC2050 with improved sustainability indicator results, reduced land sprawl (which averages 16% in BAU) and positive cost–benefit results. Nonetheless, inequality and segregation are a common concern. In addition, whilst PBA indicates a significant decrease (average decrease from 4.7 to 1.3 tCO2eq per capita) CBA demonstrates rising overall emissions from an average of 11 to 14.8 tCO2eq per capita. This is linked to rising affluence and consumption trends despite local improvements in GHG emissions, which highlights a need for cities to address consumption-based emissions.

Comparing a global high-resolution downscaled fossil fuel CO2 emission dataset to local inventory-based estimates over 14 global cities

BACKGROUND

Compilation of emission inventories (EIs) for cities is a whole new challenge to assess the subnational climate mitigation effort under the Paris Climate Agreement. Some cities have started compiling EIs, often following a global community protocol. However, EIs are often difficult to systematically examine because of the ways they were compiled (data collection and emission calculation) and reported (sector definition and direct vs consumption). In addition, such EI estimates are not readily applicable to objective evaluation using modeling and observations due to the lack of spatial emission extents. City emission estimates used in the science community are often based on downscaled gridded EIs, while the accuracy of the downscaled emissions at city level is not fully assessed.

RESULTS

This study attempts to assess the utility of the downscaled emissions at city level. We collected EIs from 14 major global cities and compare them to the estimates from a global high-resolution fossil fuel CO2 emission data product (ODIAC) commonly used in the science research community. We made necessary adjustments to the estimates to make our comparison as reasonable as possible. We found that the two methods produce very close area-wide emission estimates for Shanghai and Delhi (< 10% difference), and reach good consistency in half of the cities examined (< 30% difference). The ODIAC dataset exhibits a much higher emission compared to inventory estimates in Cape Town (+ 148%), Sao Paulo (+ 43%) and Beijing (+ 40%), possibly related to poor correlation between nightlight intensity with human activity, such as the high-emission and low-lighting industrial parks in developing countries. On the other hand, ODIAC shows lower estimates in Manhattan (- 62%), New York City (- 45%), Washington D.C. (- 42%) and Toronto (- 33%), all located in North America, which may be attributable to an underestimation of residential emissions from heating in ODIAC's nightlight-based approach, and an overestimation of emission from ground transportation in registered vehicles statistics of inventory estimates.

CONCLUSIONS

The relatively good agreement suggests that the ODIAC data product could potentially be used as a first source for prior estimate of city-level CO2 emission, which is valuable for atmosphere CO2 inversion modeling and comparing with satellite CO2 observations. Our compilation of in-boundary emission estimates for 14 cities contributes towards establishing an accurate inventory in-boundary global city carbon emission dataset, necessary for accountable local climate mitigation policies in the future.

The Exploration of Urban Material Anabolism Based on RS and GIS Methods: Case Study in Jinchang, China

As an open artificial ecosystem, the development of a city requires the continuous input and output of material and energy, which is called urban metabolism, and includes catabolic (material-flow) and anabolic (material-accumulation) processes. Previous studies have focused on the catabolic and ignored the anabolic process due to data and technology problems. The combination of remote-sensing technology and high-resolution satellite images facilitates the estimation of cumulative material amounts in urban systems. This study focused on persistent accumulation, which is the metabolic response of urban land use/urban land expansion, building stock, and road stock to land-use changes. Building stock is an extremely cost-intensive and long-lived component of cumulative metabolism. The study measured building stocks of Jinchang, China’s nickel capital by using remote-sensing images and field-research data. The development of the built environment could be analyzed by comparing the stock of buildings on maps representing different time periods. The results indicated that material anabolism in Jinchang is a distance-dependent function, where the amounts and rates of material anabolism decrease with changes in distance to the central business district (CBD) and city administration center (CAC). The cumulative metabolic rate and cumulative total metabolism were observed to be increasing, however, the growth rate has decreased.

Decentralized Valorization of Residual Flows as an Alternative to the Traditional Urban Waste Management System: The Case of Peñalolén in Santiago de Chile

Urban residual flows contain significant amounts of valuable nutrients, which, if recovered, could serve as input for the own city needs or those of its immediate surroundings. In this study, the possibilities for decentralized recovery of nutrient rich residual flows in Santiago, Chile, are studied by means of a case study considering technical and socio-economic criteria. In particular, we calculate circularity indicators for organic matter (OM), nitrogen (N), and phosphorus (P) and cost–benefits of household and community on-site technological alternatives. Kitchen waste (KW) and garden residues (GR) as well as urine were considered as system inputs whereas urban agriculture, municipality green, or peri-urban agriculture were the considered destinations for nutrients recovered. The technologies studied were anaerobic digestion, vermicomposting, and composting, while urine storage and struvite precipitation were considered for nutrient recovery from urine. Material flow analysis was used to visualize the inputs and outputs of the baseline situation (the traditional urban waste management system), and of the different household and municipality resource recovery scenarios (the decentralized valorization systems). Our findings show that decentralized valorization of KW and GR are a clear win–win policy, since they can not only produce important environmental benefits for the city in the long run, but also important cost savings considering the landfill fees and residues transportation of the current centralized waste management system.

Conceptualizing Household Energy Metabolism: A Methodological Contribution

Urban metabolism assessments enable the quantification of resource flows, which is useful for finding intervention points for sustainability. At a household level, energy metabolism assessments can reveal intervention points to reshape household energy consumption and inform decision-makers about a more sustainable urban energy system. However, a gap in the current urban metabolism research reveals that existing household energy consumption studies focus on outflows in the form of greenhouse gas emissions, and have been mostly undertaken at the city or national level. To address this gap, this study developed a method to assess household energy metabolism focusing on direct energy inflows in the form of carriers, and through-flows in the form of services, to identify intervention points for sustainability. Then, this method was applied to assess the energy metabolism of different households in Cape Town, South Africa, as categorized by income groups. The study argued that the developed method is useful for undertaking bottom–up household energy metabolic assessments in both formal and informal city settings in which more than one energy carrier is used. In cities where only national or city-level data exists, it provides a method for understanding how different households consume different energy carriers differently.

A new type of cities for liveable futures. Isobenefit Urbanism morphogenesis

Future cities? A morphogenetic code idea is presented. We need a conceptually different concept of cities which paradigmatically shifts their forms and structures toward more liveable future environments, both for us and our planet. The Isobenefit Urbanism is conceived within a medium-long term perspective mixing a macro top-down planning with a micro bottom-up spontaneous evolution in an attempt to moderate the human forces which typically induce agglomeration benefits and costs, maintaining the former while limiting the latter. It indicates a simple urban morphogenetic code to generate cities that are walkable, carless, low carbon, connected, compact, multifunctional settlements throughout nature, with unplanned forms and dinamically unlimitedly changeable/extendable, in which one can feel both urbanity and nature. By holding constant the number of inhabitants of a usual city/megacity, its Isobenefit city counterpart would enjoy the same (or greater) economies of scale benefits but without most of their costs. The Isobenefit Urbanism model might offer a potential solution to wild cementification, urban heat island effects, destruction of natural land and biodiversity, carbon emissions, congestion, air pollution, urbanicity and mental well-being, as well as provide a model to host the 3 billion new urban dwellers of the next few decades. Its ambition is to enjoy the economies of agglomeration without incurring to their diseconomies, manifested by sublinear and superlinear outputs scaling with city (population) size, typically infrastructural the former and socioeconomic the latter, without misusing lands and compromising daily rural/natural contacts.

Circular Area Design or Circular Area Functioning? A Discourse-Institutional Analysis of Circular Area Developments in Amsterdam and Utrecht, The Netherlands

The hypothesis of this paper is that the circular economy (CE) has the potential to (re)balance the conflict within urban spatial planning between ‘place as a location’ and the ‘organization of space’. The former dominates the latter following a shift from a Fordist towards a finance and real-estate driven regime. A consequence is that existing manufacturing areas are increasingly transformed into residential and commercial areas. However, this conflicts with the rationale of CE, namely that to end the linear economy, externalized activities, such as the (re)manufacturing of waste, should be internalized again, especially within urban regions. Emphasized by the EU, The Netherlands have the ambition to become fully circular in 2050. To test our hypothesis, we focus on two ongoing circular area developments in Amsterdam and Utrecht. By performing a discourse-institutional analysis, we detect in both case studies a change in discourse towards CE. Our results show that in contrast to our hypothesis, the concept of circularity is not emphasizing the ‘organization of space’, but even accelerating ‘space as a location’, increasingly transforming urban industrial areas into circular built residential and commercial areas. We conclude with spatial policy recommendations regarding the ambitions of a future CE.

Dynamic Assessment of Construction Materials in Urban Building Stocks: A Critical Review

There is a lack of understanding on the different types of dynamics of building stocks, in real life and in models. Moreover, there is now a particular interest in the embodied impacts of construction materials, since with the increasing efficiency of buildings operation, embodied impacts gain more importance in the overall building life cycle. This critical review wants to advance the understanding of the type of dynamics, methods, and tools used. The well-known IPAT equation is adapted for building stocks and three dynamics are defined: spatial, evolutionary temporal, and spatial-cohort dynamic. A framework is defined that can help researchers choose a method, tool, and dynamics of input parameters depending on their research goal, case study, and data. Moreover, generally valid conclusions are drawn, including MFA is useful to model spatially dynamic material flows; GIS is needed to include spatial dynamics. Retrofit, compared to construction and demolition, is understudied and usually analyzed through top-down methods. Material intensity and emission intensity are rarely modeled in a dynamic way. Overall, scholars seem to perform increasingly data intensive and complex studies tailored to a specific case study. However, there are big differences in the quality depending on the dynamic of input parameters.

Circular and Flexible Indoor Partitioning—A Design Conceptualization of Innovative Materials and Value Chains

This article sheds light on the materialization and operation of residential partitioning wall components in relation to circular and flexible performance. The hypothesis is twofold: (1) A stronger integration of materialization and operation aspects is indispensable in establishing sustainable value-models, and (2) recent innovations, concerning the reversibility of material connections, will help disrupting the status-quo in that respect. Attention is drawn to renewable natural fibre composites (NFC), reversible adhesives, and biodegradable insulation materials. After a background sketch regarding the notion of time, change, and material circularity in design and planning, the housing challenge in the Amsterdam metropolitan area (AMA, the Netherlands) is described. Next, a design conceptualization stage is introduced, informed by two methods and tools in particular: Circ-Flex assessment, and activity-based spatial material flow analysis. Results of the conceptualization stage are presented regarding materialization and operation, culminating in Circ-Flex partitioning components, more specifically: Side panels and insulation. It was found that NFC can tackle current issues relating, most prominently, to circularity performance. Associated modifications in the value-chain occur, above all, in raw material sourcing, manufacturing, reutilization logistics, and data-sharing. The outcomes are valid for multiple building components other than indoor partitioning, such as kitchens and furniture, but also insulation—and interior side-sheeting—of walls and roofs in energy-renovations.

Coupling and metabolic analysis of urbanization and environment between two resource-based cities in North China

Background

The complex relationship between urbanization and environment in resource-based cities is of increasing concern.

Methods

As typical examples of rapid economic growth, obvious urbanization, and successful transformed production models, the cities of Dongying and Binzhou in Yellow River Delta High-tech Economic Zone were chosen for research. First, this study examines the coupling relationship between urbanization and the environment over the last seventeen years using the coupling degree model. Second, the emergy analysis method is used to further study the energy metabolism and environmental load in the two cities to reveal these couplings.

Results

Dongying and Binzhou were well-coupled and the coupling coordination degree was in the stage of mild coordination coupling showing an upward trend. The total metabolic energy of the two cities increased yearly from 2000 to 2016, and the emergy extroversion ratio data showed the cities’ dependence on external elements such as continuously increased imported resources. The total emergy used in the two cities showed an upward trend during 2000 and 2016, while the emergy per capita consumption increased significantly, suggesting that the society’s energy efficiency improved. During the same period, the environmental loading ratio increased gradually, and the elements causing the environmental load shifted from internal to external.

Discussion

The study shows that the factors of environmental load in developing cities are gradually shifting from internal to external, which is vital to understanding the impact of urban transformation and upgrading of resource-based cities on the environment.

Pathways to Modelling Ecosystem Services within an Urban Metabolism Framework

Urbanisation poses new and complex sustainability challenges. Socio-economic activities drive material and energy flows in cities that influence the health of ecosystems inside and outside the urban system. Recent studies suggest that these flows, under the urban metabolism (UM) metaphor, can be extended to encompass the assessment of urban ecosystem services (UES). Advancing UM approaches to assess UES may be a valuable solution to these arising sustainability challenges, which can support urban planning decisions. This paper critically reviews UM literature related to the UES concept and identifies approaches that may allow or improve the assessment of UES within UM frameworks. We selected from the UM literature 42 studies that encompass UES aspects, and analysed them on the following key investigation themes: temporal information, spatial information, system boundary aspects and cross-scale indicators. The analysis showed that UES are rarely acknowledged in UM literature, and that existing UM approaches have limited capacity to capture the complexity of spatio-temporal and multi-scale information underpinning UES, which has hampered the implementation of operational decision support systems so far. We use these results to identify and illustrate pathways towards a UM-UES modelling approach. Our review suggests that cause–effect dynamics should be integrated with the UM framework, based on spatially-specific social, economic and ecological data. System dynamics can inform on the causal relationships underpinning UES in cities and, therefore, can help moving towards a knowledge base tool to support urban planners in addressing urban challenges.

Research on the synergy of urban system operation-Based on the perspective of urban metabolism

Cities have been posing threats to local environment due to intensive human activities. Disordered urban metabolism can lead to unhealthy urban system operation. Studying urban metabolism can identify the characteristics and structure of urban system operations, thereby promoting sustainable development. We construct an ecological network to model the energy/material flows among the sectors of urban system in Beijing, Shanghai, Tianjin, and Chongqing, which are the most representative cities of China. Ecological network analysis was introduced to survey the system's characteristic of structure and function. Results show that Shanghai's urban metabolic system has the highest synergism with a value of 5.04, followed by Beijing, Chongqing, and Tianjin. Different cities vary considerably in terms of the relationships among the sectors. In Beijing and Chongqing, there is mutualistic relationship between environment and primary industry. Transportation forms a mutualistic relationship with tertiary industry and other sectors Only in Chongqing. The good relationships between primary industry and construction are merely seen in Beijing and Shanghai. However, some relationships are similar in the four cities, for instance, all the relationships between primary industry and advanced industry, and between construction and advanced industry are competition; All the relationships between environment and transportation are mutualism. We further explored the network stability and found that the studied urban systems are all located in a stable status relatively. Our research could reveal the synergy of urban operation, and provide a theoretical basis for optimizing urban metabolic processes by regulating the flows and guidance for sustainable urban development.

Using OpenStreetMap point-of-interest data to model urban change-A feasibility study

User-generated content is a valuable resource for capturing all aspects of our environment and lives, and dedicated Volunteered Geographic Information (VGI) efforts such as OpenStreetMap (OSM) have revolutionized spatial data collection. While OSM data is widely used, considerably little attention has been paid to the quality of its Point-of-interest (POI) component. This work studies the accuracy, coverage, and trend worthiness of POI data. We assess the accuracy and coverage using another VGI source that utilizes editorial control. OSM data is compared to Foursquare data by using a combination of label similarity and positional proximity. Using the example of coffee shop POIs in Manhattan we also assess the trend worthiness of OSM data. A series of spatio-temporal statistical models are tested to compare change in the number of coffee shops to home prices in certain areas. This work overall shows that, although not perfect, OSM POI data and specifically its temporal aspect (changeset) can be used to drive urban science research and to study urban change.

New Dimensions for Circularity on Campus—Framework for the Application of Circular Principles in Campus Development

To what extent can transformation and development processes on a university or other campus fit in with the principles of circularity? This paper builds a bridge between the more theoretical approach of the circular economy and daily practice in campus development, using semi-structured in-depth interviews with a broad range of stakeholders in university management in Dutch universities. The study aims to show possible perspectives and offers insight into which factors are important for the sustainable development of a university or other campus, taking into account the principles of the circular economy. The paper introduces a framework for understanding the various dimensions and scales of campus operations. The aim is to make a practical contribution to the implementation of circular principles in campus development. The main conclusions are that circularity is an organisational issue, complexity must be reduced, and integral policy and specialised knowledge are required. Five recommendations towards an integrated strategy for circularity in campus development are given.

Urban Metabolic Analysis of a Food-Water-Energy System for Sustainable Resources Management

Urban metabolism analyzes the supply and consumption of nutrition, material, energy, and other resources within cities. Food, water, and energy are critical resources for the human society and have complicated cooperative/competitive influences on each other. The management of interactive resources is essential for supply chain analysis. This research analyzes the food-water-energy system of urban metabolism for sustainable resources management. A system dynamics model is established to investigate the urban metabolism of food, water, and energy resources. This study conducts a case study of Shihmen Reservoir system, hydropower generation, paddy rice irrigation of Taoyuan and Shihmen Irrigation Associations, and water consumption in Taoyuan, New Taipei, and Hsinchu cities. The interactive influence of the food-water-energy nexus is quantified in this study; the uncertainty analysis of food, water, and energy nexus is presented.

Beyond Wastescapes: Towards Circular Landscapes. Addressing the Spatial Dimension of Circularity through the Regeneration of Wastescapes

Wastescapes are the result of unsustainable linear growth processes and their spatial consequences within the context of urban metabolic flows and related infrastructure. They represent the operational infrastructure for waste management and include Drosscapes, generating complex relations with the servicing and surrounding territory. In particular, the peri-urban areas are spatially affected by these processes. This often leads to ineffective use and/or abandonment because they are currently impossible to use, demanding impactful (and often expensive) regeneration and revalorization to make them usable again. Being part of the urban metabolic process, wastescapes are in a continuous state of dynamic equilibrium. They can be considered crucial areas from a metropolitan perspective because they have the potential to become innovative spatial contexts or resources in a Circular Economy (CE), which aims to overcome the crises of both resource scarcity and spatial fragmentation. However, common and shared definitions of wastescapes are still missing at the European policy level, as only classical categories of material waste are generally mentioned. Wastescapes can be considered as ‘potentiality contexts’ where developing, testing, and implementing Eco-Innovative Solutions (EIS) can be done. By doing so, wastescapes can help start transitions towards a CE. This can be achieved by using Peri-urban Living Labs (PULL), which have the potential to be the virtual and physical environments in which experimenting the collaborative co-creation process for developing EIS can be done. Doing so will allow for the improvement of waste management and for the revalorization of wastescapes in collaboration with all potential stakeholders.

Urban Mobility and Greenhouse Gas Emissions: Status, Public Policies, and Scenarios in a Developing Economy City, Natal, Brazil

This study aims to deepen the understanding of the role of the urban mobility sector in the current and future greenhouse gas (GHG) emissions of a middle-sized city of Brazil, which is also a developing economy. With the cross-reference between road and rail mobility data, governmental mobility planning, the Global Protocol for Community-Scale Greenhouse Gas Emission Inventories (GPC) of the Intergovernmental Panel on Climate Change (IPCC) emission quantification methodology, and the creation of scenarios for up to 10 subsequent years, it is possible to verify that individual motorized transport accounts for 60% of the total emissions from the urban transportation sector, with the largest amount of carbon dioxide equivalent (CO2eq) emissions per passenger among all of the forms of mobility. However, in the case of this study, government mobility planning, by not encouraging more energy-efficient transport and non-motorized modes, ends up aggravating GHG emissions in the scenarios considered for 2020 and 2025. In turn, the mitigation scenarios proposed herein integrate public transport and non-motorized transport solutions that would reduce the total of equivalent carbon dioxide (tCO2eq) by at least 45,000 tCO2eq per year by 2025. This cross-referencing of the environmental impact of government mobility policies can be replicated in other cities in developing countries that do not yet present municipal inventories or emission monitoring.

Large cities get more for less: Water footprint efficiency across the US

Many urban indicators and functional citywide properties have been shown to scale with population due to agglomeration effects. We hypothesize that scaling relations may also exist for water-related urban indicators such as the water footprint. The water footprint is an indicator of water use that measures humans' appropriation of freshwater resources. We analyze the scaling of the water footprint for 65 mid- to large-sized US cities using both empirical estimates and a social interaction network model of city functioning. The network model is used to explain the presence of any scaling exponent in the empirical estimates of the urban water footprint by linking to previous theories of urban scaling. We find that the urban water footprint tends to approximately show sublinear scaling behavior with both population and gross domestic product. Thus, large cities tend to be more water footprint efficient and productive than mid-sized cities, where efficiency and productivity are quantified, in a broad sense, as deviations from a linear scaling exponent. We find the sublinear scaling may be linked to changes in urban economic structure with city size, which lead to large cities shifting water intensive economic activities to less populated regions. In addition, we find that green water contributes to the scaling both positively by transferring the dependence of food consumption on population into the water footprint and negatively by increasing heterogeneity. Overall, the proposed scaling relations allow for the comparison of water footprint efficiency and productivity of cities. Comparing these properties and identifying deviations from the expected behavior has implications for water resources and urban sustainability.