A significance of smart city pilot policies in China for enhancing carbon emission efficiency in construction

The Chinese government seeks to promote economic growth and sustainable development while achieving carbon neutrality by establishing phased smart city pilots. Therefore, it is important to study whether smart city pilots can promote carbon emission efficiency (CEE). This paper constructs a multi-period difference-in-difference (DID) model based on panel data from 241 prefecture-level cities in China from 2007 to 2019, aiming to investigate the mechanism of the impact of smart city pilot policies (SCPP) on CEE and whether there is a rebound effect. The study found that smart city construction (SCC) significantly improves carbon efficiency, with pilot cities increasing their CEE by 1.4% compared to non-pilot cities. The conclusions remain robust under a variety of scenarios including the introduction of placebo tests, counterfactual tests, sample data screening, and omitted variable tests. The results of the mechanism test show that although the rebound effect can inhibit the improvement of CEE, the environment can be improved and the CEE can be enhanced through green technology innovation, industrial structure upgrading, energy structure optimization, environmental regulation effect, information technology support, and resource allocation effect. The heterogeneity results indicate that the SCPP is more effective in promoting CEE in cities in the eastern region, southern cities, environmentally friendly cities, large cities, and medium-sized cities. This study contributes to the existing literature in clarifying the environmental benefits of SCPP and provides valuable policy insights for cities to address climate change and sustainable development.

Characteristics and effects of global sloping land urbanization from 2000 to 2020

Cities usually expand on flat land. However, in recent decades, the increasing scarcity of available flat land has compelled many cities to expand to sloping land (sloping land urbanization, SLU), and the understanding for global SLU is still unclear. This study, based on the currently available high-precision global Digital Elevation Model (FABDEM) and global land cover dataset (GlobeLand30), investigated the characteristics and impacts of SLU in 26,402 urban residential areas worldwide from 2000 to 2020. Results show that the total area of SLU globally is 16,383 km2, accounting for 9.54 % of the overall urban expansion. This phenomenon is widespread globally and relatively concentrated in a few countries, with 42.78 %, 24.35 %, and 21.83 % of the area coming from cultivated land, forest, and grassland respectively. Global SLU has accommodated 34.78 million urban population, and indirectly protected 8922 km2 of flat cultivated land, while causing a net loss of 4372 km2 of green ecological land. Deliberately balancing the dual effects of SLU is crucial for advancing sustainable global urbanization.

The role of the environmental subsystem in sustainable urban development: Evidence from megacities in China

Conflicts in urban subsystems have severely hindered the realization of sustainable development, among which the most serious is the conflict between the environmental subsystem and urban development. Differing from studies considering individual environmental elements, this paper innovatively investigates the quantitative relationship between overall environmental performance and other development dimensions to understand the quantitative role of the environmental subsystem in sustainable urban development. Taking the nine megacities in China as an example, this paper first develops the performance variables of four urban subsystems, including the environment, by entropy method and analyzes the conflict or coordination level between the environment and other subsystems through the coupling coordination degree model (CCDM). Then, the interaction mechanism is further analyzed by the fully modified ordinary least square (FMOLS) and vector error correction model (VECM). This paper tries to provide a new reference for management and decision-making by focusing on the whole environmental subsystem rather than separate elements, which is of theoretical and practical significance. The main conclusions are as follows: (1) The coordination level between the environment and other urban subsystems is low; (2) 1 % rise in the economic and resource performance can respectively lead to 0.2014 % and 0.1388 % declines in the environmental performance; (3) 1 % increase in social performance can bring a 0.3738 % rise in environmental performance; (4) Improving environmental and resource subsystems' performance is the priority; (5) Coordinating urban subsystems is the key to long-run sustainable development. Despite the case studies on megacities in China, we hope to provide a new reference for cities worldwide with concentrated populations, rapid growth, and complex development contradictions.

Lessons learned from a study based on the AHP method for the assessment of sustainability in neighborhoods

The Analytic Hierarchy Process (AHP) is a method that allows complex decisions to be made from impartiality, making it suitable for reaching a consensus among experts seeking to solve a problem. This method has been successfully applied in other investigations, and its use has been extended to several disciplines. This technical paper presents the lessons learned from a study that relied on the AHP method to determine priority aspects for sustainable neighborhoods. The research is developed in three replicable phases. In each of them, aspects that are recommended to be considered are detailed, for example, in the formulation of the hierarchical structure, selection of experts, expert survey design, and information processing for the determination of weights and levels of importance.•The utilization of software to apply the AHP method can help researchers to optimize time and resources.•Social networks proved to be more effective than conventional methods for identifying and contacting experts.•Subjective sustainability issues can be prioritized by expert consensus.

Does urban growth mean the loss of greenness? A multi-temporal analysis for Chinese cities

Urban growth is recognized as the conversion of vegetated surface to built-up surface. However, there is still no consensus about the urbanization-induced dynamic of vegetation greenness in view of existing literatures. In this study, we aimed to empirically investigate whether urban growth mean the loss of vegetation greenness. We selected 340 Chinese cities as the study areas, relied on consistent multi-temporal remotely sensed data and adopted linear regression analysis, annual growth area, Tail-Sen slope and Mann-Kendall models. Results show that although vegetation greening generally lagged behind urban growth in the monitoring period, a tendency of their consistent speeding up can be observed over time. By categorizing four forms and four trends of vegetation greenness dynamics related to urban growth, we revealed the diversity of Chinese cities. The former focused on the velocity of urban growth and vegetation greenness dynamics within newly urbanized area in three phases, i.e., 2003-2008, 2008-2013 and 2013-2018. The latter focused on the interannual trends of vegetation greenness dynamics among the previously existing and newly urbanized areas. The key finding is that, in over 85 % of the cities, we measured an increase of vegetation greenness along with urban growth. In addition, our detailed results allow quantifying the impact of urbanization in Chinese cities on vegetation protection and sustainable development.

Nature-based solutions: Establishing a comprehensive framework for addressing urban waterlogging management

Due to the impact of global climate change, many cities in China have been hit by severe rainstorms, leading to increasingly frequent urban waterlogging disasters. In recent years, nature-based solutions (NbS) have received widespread attention and recognition, providing new ideas and approaches to addressing urban waterlogging issues. First, this article reviews the development process and concept of NbS and analyzes its core ideas and principles. Second, it analyzes the guiding role of NbS in urban waterlogging management and compares the commonalities and differences between NbS and three related waterlogging concepts. To ensure that urban waterlogging management is operational and dynamic, and that there is effective communication among stakeholders, this article proposes a comprehensive framework for the application of NbS in urban waterlogging management. Finally, this article analyzes the opportunities and potential of NbS applied to urban environmental issues. Integr Environ Assess Manag 2023;19:1414-1421. © 2023 SETAC.

The effects of multilayer blue-green roof on the runoff water quality

In the context of climate changes, characterized by an increase of short but intense rainfall events and rise of the average temperature, the fast population growth and consequent urbanization require the implementation of innovative solutions to mitigate pluvial floods and, at the same time, reduce the water demand. Among the different nature-based solutions, multilayer blue-green roofs have been widely recognized for their high capacity of reducing runoff generation from rooftops, and their additional storage layer enables to collect water, which could be reused for different purposes. However, the quality of the collected water in a multilayer blue-green roof and the influence that the additional storage layer has on it have not been analysed yet. Following this knowledge gap, we investigated the potential benefits of a multilayer blue-green roof installed in Cagliari, with respect to a traditional roof. The outflow triggered by artificial irrigation and natural rainfall events was analysed, both from a quantitative and qualitative perspective. Results confirm the high contribution of multilayer blue-green roofs in mitigating runoff generation, which is however influenced by antecedent soil moisture and water level conditions. The outflow from the multilayer blue-green roof presents lower suspended solids and heavy metals concentrations than from a traditional roof. On the other hand, Carbon Oxigen Demand (COD) concentrations in the multilayer blue-green roof outflow exceed the limits defined by the Italian regulations (125 mg/l) for water discharge or reuse, partially due to the high residence time in the storage layer. Specific treatments could be planned to reuse the collected water for urban purposes.

Ethiopian urban land allocation policy and its contribution to urban densification

Urban densification is considered as the best tool for efficient urban land utilization, containment, and minimizing urban development costs. It is also a widely accepted approach to mitigate shortages of urban land and urban sprawl. With this in mind, Ethiopia has adopted a standard-based urban land allocation policy. The policy relies on population size during the urban planning process to address issues related to sustainable urban development by increasing the densities of its urban areas. However, the impact of the existing urban land allocation policy on urban densification has not been investigated adequately. Thus, this study examines the contribution of existing urban land allocation policies to urban densification in Ethiopia. A mixed research approach was employed to achieve the objective of the study. The study revealed that the policy gives more attention to the immediate and tangible conditions than the efficient use of land resources. Therefore, it allocated an average of 223 square meters of land to each person for urban development. The study implies that the country's urban land allocation policy is ineffective in achieving the intended outcome of urban densification. Instead, coupled with uncontrolled urban population growth, it has been exacerbating the rapid horizontal expansion of urban areas. With the current trend of horizontal expansion of urban areas, the country's land resources is expected to be converted into a built-up environment within the next 127 years unless the policy is radically changed. Thus, this paper calls for revisiting the existing urban land allocation strategy of the country in a way that responds towards efficient urban land allocation and sustainable urban development.

The local coupling and telecoupling of urbanization and ecological environment quality based on multisource remote sensing data

Coordinating the relationship between urbanization and ecological environment quality (EEQ) is crucial to achieving sustainable development. With the development of globalization, the pattern of remote interaction between urbanization and EEQ has gradually increased. However, the current study on the coupling of urbanization and EEQ lacks a remote perspective, and the remote sensing ecological index (RSEI) model has not yet considered the environmental pollution caused by population agglomeration. For these reasons, this study proposes the remote sensing ecological environment index (RSEEI) model and measures the local coupling and telecoupling coordination degree (LTCCD) of urbanization and EEQ in China from 2000 to 2020. According to the results, the rate of change of EEQ in China was -0.00011a^-1. RSEEI widens the gap between the east and west of EEQ, differentiated by the Heihe-Tengchong Line. China's urbanization is growing at a 0.0008a^-1 rate, with a spatially driven radiation potential with Beijing, Shanghai, Hong Kong, and Macao as the core. LTCCD follows an increasing trend from inland to coastal and west to east. Over 70% of provinces experienced a shift in adjacent LTCCD levels, and 14 provinces moved from disorder to coordination after 2010. The telecoupling strengthens the correlation between urbanization and EEQ among regions compared with traditional coupling. In addition, the eastern coastal areas, the northern and central-south inland areas, and the northwest face different coordination problems.

Mapping ecosystem services for ecological planning and management: a case from a tropical planning region, Eastern India

Burdwan City experienced an important urbanization trend inducing dramatic land use/land cover (LULC) changes over the past 28 years. However, their effects on ecosystem services value (ESV) remain unknown. The prime objective of this study is to analyze the spatial heterogeneity of ESV in the Burdwan Planning Area (BPA) from 1990 to 2018. Ecosystem service value (ESV) was estimated using the benefits transfer method, and the contribution of LULC was also computed using contribution rate (CR). The dynamics of LULC were also calculated from the change intensity index and single LULC dynamics. The sensitivity of ESVs to LULC using an elasticity indicator between 1990 and 2018 was performed. The results showed that during the entire study period, built-up are and open lands or sand bars increased 362.34% and 42.40%; water bodies, vegetation, and agricultural lands decreased by 33.24%, 7.20%, and 13.66%, respectively, from 1990 to 2018. In case of ESV, total ESVs were US $95.26 (1990), US $95.85 (2000), US $95.42 (2010), and US $91.38 (2018) million. There was a reduction of the total ESV of US $3.88 million between 1990 and 2018. A substantial spatial heterogeneity of ESV between rural and urban landscapes was reported due to variations of ecological landscapes. The main driver of ESs value loss was a rapid conversion of natural land cover (vegetation, water bodies) into semi-natural or artificial landscapes, i.e., urban settlement. Being a planning region, assessing the impact of LULC dynamics on the ESVs is necessary for sustainable urban development and effective urban environmental management.

Quantifying COVID-19 recovery process from a human mobility perspective: An intra-city study in Wuhan

The COVID-19 pandemic has brought huge challenges to sustainable urban and community development. Although some recovery signals and patterns have been uncovered, the intra-city recovery process remains underexploited. This study proposes a comprehensive approach to quantify COVID-19 recovery leveraging fine-grained human mobility records. Taking Wuhan, a typical COVID-19 affected megacity in China, as the study area, we identify accurate recovery phases and select appropriate recovery functions in a data-driven manner. We observe that recovery characteristics regarding duration, amplitude, and velocity exhibit notable differences among urban blocks. We also notice that the recovery process under a one-wave outbreak lasts at least 84 days and has an S-shaped form best fitted with four-parameter Logistic functions. More than half of the recovery variance can be well explained and estimated by common variables from auxiliary data, including population, economic level, and built environments. Our study serves as a valuable reference that supports data-driven recovery quantification for COVID-19 and other crises.

Impact of urban innovation on urban green development in China's Yangtze River Economic Belt: perspectives of scale and network

Understanding whether and how urban innovation offers a sound solution to the dilemma of urban green development is a crucial response to mitigate the detrimental effect on natural resources and environment for transitioning to sustainable urban development. To address the critical issue, we propose urban green development evaluation index system, and then examine how the urban innovation affects urban green development from the perspectives of government-scale, enterprise-scale, and spatial correlation network, all of which are originally applied in the 108 cities of Yangtze River Economic Belt of China (YREB) during period 2006-2018. The evaluation results show that urban innovation promotes urban green development, and both government-scale and enterprise-scale contribute to the effects. The constructed spatial correlation network of urban innovation illustrates the network structural form and reveals the network property, and further results tell that increasing network density and centrality would promote green development obviously. More specifically, the network density of urban innovation has been tied to the enhancement of urban green development, which is more significant in middle reaches than in lower and upper reaches of YREB. Similarly, optimizing the network's degree centrality and closeness centrality can help facilitate urban green development in whole YREB. Thus, the research findings would provide new insights into the essence and driving forces from various scale and hidden network when exploring and seeking urban green development path.

Emerging paradigm shift in urban indicators: Integration of the vertical dimension

Since new urbanism strategies encourage higher density and compact city development, it is expected that the height of urban environments will increase in the next few years as a remedy for many urban problems such as urban sprawl, cost of living, and detrimental environmental impacts of horizontal development of cities. Therefore, urban designers and planners should consider the third dimension of cities according to the vertical growth paradigm that is inherently a three-dimensional (3D) socioeconomic and environmental process. While a large body of literature is focusing on horizontal or two-dimensional (2D) urban indicators, it still lacks more research to compare 2D and 3D urban indicators. In this study, urban environment quality indicators, as a prominent example of urban indicators, were measured in two and three dimensions in the central business district of Urmia in Iran. Also, a Pearson's correlation analysis was performed to find a pairwise relationship between indicators. The results of the correlation analysis revealed that most 3D indicators have no significant linear relationship with other indicators, so predicting 3D indicator values based on other indicators is a difficult or even impossible task. Comparing 2D indicators with 3D ones shows that approximately 30 percent of the study area has a different urban environmental quality if it integrates the vertical dimension with 2D indicators. In addition, measuring and modelling 3D indicators provide better locational information on urban conditions and the life of citizens than traditional 2D urban indicators. This study recommends planning for the expansion of 3D information and associated tools that lead to deeper analytical insights into 3D Urban Environmental Quality assessment.

Housing developers' perceived barriers to implementing municipal sustainability requirements in Swedish sustainability-profiled districts

Swedish municipalities are taking an active role in shaping and implementing sustainability-related policies in urban development by initiating and governing sustainability-profiled district developments on municipally owned land. To drive sustainable development and innovation in these districts and develop future policies, municipalities use land allocation agreements to set project-specific sustainability requirements on housing development projects that go beyond the current national building regulations. Developers play a key role in implementing these municipal sustainability requirements. The purpose of this paper is to explore housing developers' perceived barriers to implementing municipal sustainability requirements in their projects, which ultimately constrain possibilities for municipalities to drive sustainable development. Findings are based on case studies of two sustainability-profiled district developments in different Swedish municipalities. Main barriers perceived by the developers could be categorized into: (1) increased costs when adapting to unforeseen changes that constrain project budgets and (2) conflicting interests and objectives between interdependent actors. These barriers are contextualised within the relationship between the developers and municipalities. Contributions are made to literature on developers' roles and perspectives in sustainability-oriented urban development. We illustrate how conflicting short-term and long-term interests between developers and municipalities complicate and impede problem solving in housing development projects. This calls for more research on these actors' interests, and how they align and conflict in these types of projects. Findings also illustrate how developers resolve issues through interactions with municipalities, indicating collaborative problem solving processes to investigate further.

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.

Sustainable metropolitan areas perspectives through assessment of the existing waste management strategies

Human activities are considered among the main producers of any kind of pollution. This paper, through a Driver-Pressure-State-Impact-Response (DPSIR) model analyses, focuses on the evaluation and assessment of the existing practices, procedures, and results obtained in order to determine whether the municipal solid waste (MSW) management implemented in three major Greek municipalities in the greater urban area of Attica, namely the municipalities of Nea Smirni, Vyronas, and Piraeus, could be considered viable and sustainable. The evaluation indicated that MSW in Greek cities have reduced over the last years, also suggesting a steady downward trend, which could be considered consistent with that of the per capita incomes in Greece due to the extended economic austerity, while at the same time the recycling indicator seems to optimize. The results are very useful for policymakers and local authorities towards taking actions related to the targets set from the circular economy strategies as well as the targets set from United Nation Development Program and the European Green Deal Strategy.

An evolution perspective on the urban land carrying capacity in the urbanization era of China

The past few decades witness a typical urbanization era in large developing countries such as China. In line with the urbanization process, land resources have inevitably presented a series of changes. The evolution of urban land carrying capacity (ULCC) is appreciated as a yardstick for guiding towards sustainable urban development. This paper therefore proposes an alternative method from carrier-load perspective for investigating the evolution of ULCC performance in China during the rapid urbanization era of 2012-2017. The data employed for analysis is collected from 290 Chinese prefectural-level cities. Results indicate that ULCC performance in the urbanizing China has been evolving towards a better state, for which 94% of the surveyed cities have made progress. However, significant disparity exists between cities on ULCC evolution performance, in particular, mega cities tend to have better ULCC evolution performance. Some cities may have better evolution performance although they have a poor average ULCC value. Contrarily, some cities may present poor evolution performance but they carry a better average ULCC value. The research findings provide valuable references not only for policy-makers to better understand the state of ULCC across the country, and appreciate inspiring experiences and lessons for implementing effective tailor-made measures to improve the ULCC performance, but also for enriching the literature in land resource management.

How smart is smart growth? Examining the environmental validation behind city compaction

Smart growth (SG) is widely adopted by planners and policy makers as an environmentally friendly way of building cities. In this paper, we analyze the environmental validity of the SG-approach based on a review of the scientific literature. We found a lack of proof of environmental gains, in combination with a great inconsistency in the measurements of different SG attributes. We found that a surprisingly limited number of studies have actually examined the environmental rationales behind SG, with 34% of those studies displaying negative environmental outcomes of SG. Based on the insights from the review, we propose that research within this context must first be founded in more advanced and consistent knowledge of geographic and spatial analyses. Second, it needs to a greater degree be based on a system's understanding of urban processes. Third, it needs to aim at making cities more resilient, e.g., against climate-change effects.

Optimization of land use decisions using binary integer programming: The case of Hillsborough County, Florida, USA

The contradiction between urban growth and environmental sustainability is a fundamental question regarding the welfare of human beings and the future of the earth. Human labor transforms the earth into factors of production by consuming its natural resources. The rational way to minimize the negative effects of such transformative intervention is advanced land use planning. Nevertheless, it is not possible to say that traditional modes of land use planning have fulfilled this task. The main reason for this failure is the habit of using traditional decision making tools which, to a significant level, are technically incompatible to deal with such a task. Hopefully, recent improvements in planning support tools have potential to process and evaluate complex geographical data. This paper benefits from these tools and moves one step further by performing a land assignment model, which operates binary integer programming and geographical information systems in a way that it can deal with different land use scenarios. This new methodology, which named as inquired land assignment model (ILAM), is applied for three different land use scenarios at upper level planning scale for a case area - Hillsborough County in Florida, USA. Outputs represent reasonable and consistent land use assignment and allocation results, and the model is potentially applicable to various fields and lower scales of planning practices by simple modifications.

Indoor PM2.5 in an urban zone with heavy wood smoke pollution: The case of Temuco, Chile

Temuco is a mid-size city representative of severe wood smoke pollution in southern Chile; however, little is known about the indoor air quality in this region. A field measurement campaign at 63 households in the Temuco urban area was conducted in winter 2014 and is reported here. In this study, indoor and outdoor (24-hr) PM_2.5 and its elemental composition were measured and compared. Infiltration parameters and outdoor/indoor contributions to indoor PM_2.5 were also determined. A statistical evaluation of how various air quality interventions and household features influence indoor PM_2.5 was also performed. This study determined median indoor and outdoor PM_2.5 concentrations of 44.4 and 41.8 μg/m³, respectively. An average infiltration factor (0.62 ± 0.06) was estimated using sulfur as a tracer species. Using a simple mass balance approach, median indoor and outdoor contributions to indoor PM_2.5 concentrations were then estimated as 12.5 and 26.5 μg/m³, respectively; therefore, 68% of indoor PM_2.5 comes from outdoor infiltration. This high percentage is due to high outdoor pollution and relatively high household air exchange rates (median: 1.06 h^-1). This study found that S, Br and Rb were dominated by outdoor contributions, while Si, Ca, Ti, Fe and As originated from indoor sources. Using continuous indoor and outdoor PM_2.5 measurements, a median indoor source strength of 75 μg PM_2.5/min was estimated for the diurnal period, similar to literature results. For the evening period, the median estimate rose to 135 μg PM_2.5/min, reflecting a more intense wood burning associated to cooking and space heating at night. Statistical test results (at the 90% confidence level) support the ongoing woodstove replacement program (reducing emissions) and household weatherization subsidies (reducing heating demand) for improving indoor air quality in southern Chile, and suggest that a cookstove improvement program might be helpful as well.

Sustainable urban systems: Co-design and framing for transformation

Rapid urbanisation generates risks and opportunities for sustainable development. Urban policy and decision makers are challenged by the complexity of cities as social-ecological-technical systems. Consequently there is an increasing need for collaborative knowledge development that supports a whole-of-system view, and transformational change at multiple scales. Such holistic urban approaches are rare in practice. A co-design process involving researchers, practitioners and other stakeholders, has progressed such an approach in the Australian context, aiming to also contribute to international knowledge development and sharing. This process has generated three outputs: (1) a shared framework to support more systematic knowledge development and use, (2) identification of barriers that create a gap between stated urban goals and actual practice, and (3) identification of strategic focal areas to address this gap. Developing integrated strategies at broader urban scales is seen as the most pressing need. The knowledge framework adopts a systems perspective that incorporates the many urban trade-offs and synergies revealed by a systems view. Broader implications are drawn for policy and decision makers, for researchers and for a shared forward agenda.

Observational evidence of a long-term increase in precipitation due to urbanization effects and its implications for sustainable urban living

Although projected precipitation increases in East Asia due to future climate change have aroused concern, less attention has been paid by the scientific community and public to the potential long-term increase in precipitation due to rapid urbanization. A ten-year precipitation dataset was analysed for both a rapidly urbanized megacity and nearby suburban/rural stations in southern China. Rapid urbanization in the megacity was evident from satellite observations. A statistically significant, long-term, increasing trend of precipitation existed only at the megacity station (45.6mm per decade) and not at the other stations. The increase was attributed to thermal and dynamical modifications of the tropospheric boundary layer related to urbanization, which was confirmed by the results of our WRF-SLUCM simulations. The results also suggested that a long-term regional increase in precipitation, caused by greenhouse gas-induced climate change, for instance, was not evident within the study period. The urbanization-induced increase was found to be higher than the precipitation increase (18.3mm per decade) expected from future climate change. The direct climate impacts due to rapid urbanization is highlighted with strong implications for urban sustainable development and the planning of effective adaptation strategies for issues such as coastal defenses, mosquito-borne disease spread and heat stress mortality.

Wood burning pollution in southern Chile: PM2.5 source apportionment using CMB and molecular markers

Temuco is a mid-size city representative of severe wood smoke pollution in southern Chile; i.e., ambient 24-h PM_2.5 concentrations have exceeded 150 μg/m³ in the winter season and the top concentration reached 372 μg/m³ in 2010. Annual mean concentrations have decreased but are still above 30 μg/m³. For the very first time, a molecular marker source apportionment of ambient organic carbon (OC) and PM_2.5 was conducted in Temuco. Primary resolved sources for PM_2.5 were wood smoke (37.5%), coal combustion (4.4%), diesel vehicles (3.3%), dust (2.2%) and vegetative detritus (0.7%). Secondary inorganic PM_2.5 (sulfates, nitrates and ammonium) contributed 4.8% and unresolved organic aerosols (generated from volatile emissions from incomplete wood combustion), including secondary organic aerosols, contributed 47.1%. Adding the contributions of unresolved organic aerosols to those from primary wood smoke implies that wood burning is responsible for 84.6% of the ambient PM_2.5 in Temuco. This predominance of wood smoke is ultimately due to widespread poverty and a lack of efficient household heating methods. The government has been implementing emission abatement policies but achieving compliance with ambient air quality standards for PM_2.5 in southern Chile remains a challenge.

Estimating greenhouse gas emissions of European cities--modeling emissions with only one spatial and one socioeconomic variable

Substantive and concerted action is needed to mitigate climate change. However, international negotiations struggle to adopt ambitious legislation and to anticipate more climate-friendly developments. Thus, stronger actions are needed from other players. Cities, being greenhouse gas emission centers, play a key role in promoting the climate change mitigation movement by becoming hubs for smart and low-carbon lifestyles. In this context, a stronger linkage between greenhouse gas emissions and urban development and policy-making seems promising. Therefore, simple approaches are needed to objectively identify crucial emission drivers for deriving appropriate emission reduction strategies. In analyzing 44 European cities, the authors investigate possible socioeconomic and spatial determinants of urban greenhouse gas emissions. Multiple statistical analyses reveal that the average household size and the edge density of discontinuous dense urban fabric explain up to 86% of the total variance of greenhouse gas emissions of EU cities (when controlled for varying electricity carbon intensities). Finally, based on these findings, a multiple regression model is presented to determine greenhouse gas emissions. It is independently evaluated with ten further EU cities. The reliance on only two indicators shows that the model can be easily applied in addressing important greenhouse gas emission sources of European urbanites, when varying power generations are considered. This knowledge can help cities develop adequate climate change mitigation strategies and promote respective policies on the EU or the regional level. The results can further be used to derive first estimates of urban greenhouse gas emissions, if no other analyses are available.