City and Environment Interactions最新文献

Urban in-migration, high birth rates and unchecked development are driving the continued growth of African cities. Much of this urbanization occurs in informal settlements, where unplanned growth exacerbates the impacts of climate hazards. Our paper explores the challenges faced by urban planners seeking to address climate change threats in African cities. Focusing on Addis Ababa, we conduct a robust policy analysis of urban government response. Our main finding is that Addis Ababa’s environmental challenges are primarily a result of urban development and inadequate planning and policy enforcement. Environmental challenges are exacerbated by rapidly intensifying climate impacts, but not driven by them. Improved city-level policy responses can potentially mitigate many of Addis Ababa’s current environmental challenges and prepare the city to weather future ones. We highlight four areas of policy weakness: (1) ineffective or absent policies concerning green space; (2) the exclusion of informal settlements from ongoing resilience planning efforts; (3) limited public trust and transparency; and (4) a lack of coordination across the multiple agencies in Addis charged with planning. Holistic, multi-stakeholder planning is inhibited by a lack of collaboration, limited stakeholder participation, and a reluctance to engage in productive dialogue. Resolving all four issues will only occur with sustained increases in social trust, expertise, governance capacity and capital.

This study explored the association between greening and social capital in neighborhoods, considering demographics and zoning by urban planning. The target area encompassed the urban areas of Kyoto City, Japan, which has a long tradition of landscape policy and neighborhood associations. Greening was evaluated using two automated methods: 1) horizontal green coverage of the land was calculated via the Normalized Difference Vegetation Index in satellite images, and 2) green visibility in streetscape from a human perspective was estimated by combining Google Street View images and a machine learning model. Public government data were used for demographics and zoning, and social capital was evaluated using survey data from the local government. After performing the elastic net models, variables that had explanatory power for each greening index were selected. Similar reasonable associations were found for each of the indices with the zoning categories. However, for both zoning and demographics, different variables were selected. Importantly, the social capital variable was selected only for the green visibility in streetscape, showing a negative correlation between them, unlike in previous studies. These results suggest that the association between urban greening and social relationships can change depending on the context of the target regions and measurements of greening.

The accessibility and utilization of Urban Green Spaces (UGSs) play a crucial role in enhancing the health benefits and overall quality of life for urban residents. However, it is evident that not just a single factor, but rather a multitude of factors, influence the accessibility and use of UGSs. Consequently, this study aims to systematically review the determinants of accessibility and use of UGSs, highlighting their complex interrelations through a socio-ecological framework. By conducting a literature review across two major databases, Scopus and Web of Science (WOS), a total of 163 articles published between 1988 and January 31, 2024, were included in this study. The analysis provides an overview of the reviewed studies, focusing on aspects such as publication year, geographical distribution, research designs, classifications of UGSs, sampling techniques, sample populations, and assessment measures. Furthermore, it identifies key determinants affecting individuals’ accessibility and use of UGSs, including personal/individual, socio-cultural, physical/environmental, institutional, transport, and psychological factors. Based on these findings, a conceptual framework is proposed to better understand the dynamics of UGS accessibility and use. This framework is designed to aid planners and designers in improving and equalizing the distribution of UGSs to meet the diverse needs of the community comprehensively and serves as a foundational guide for future research.

Non-conventional water supplied from Bole Lemi Industrial Park (BLIP) in Addis Ababa, Ethiopia is treated to remove contaminants, but never has been analyzed for its quality for urban agriculture (UA) use. The objective of this study is to analyze the quality of treated wastewater (TWW) using treated wastewater quality index (TWWQI). Treated wastewater samples were taken at the influent and effluent of the wastewater treatment plant located within BLIP. The physico-chemical properties of the water samples from BLIP were analyzed at the third-party laboratory. The result showed that the aggregate TWWQI value falls under the category of very poor water for urban irrigation agriculture (UIA) use. This very poor water quality grade attributes 85 % to the presence of heavy metals, 4 % to nutrients load, 8 % to saline condition contributors and 4 % to miscellaneous contaminants. Discrete analyses of the indices for heavy metals, nutrient loads, saline condition contributors and miscellaneous contaminants shifted the water quality from very poor to very polluted, excellent, poor and good for UIA use respectively. Though the aggregate TWWQI is of very poor category for UIA use, the treatment plants of BLIP exhibited contaminants removal efficiencies of between 30 and 100 % with aggregate removal efficiency of 58 %. Results also revealed that there were contaminants that exhibited higher effluent values than influent after treatment indicating the failure of BLIP’s treatment plants to remove these contaminants. In conclusion, treated wastewater from BLIP, falls under very poor water category for use in irrigation agriculture where Cr⁺³, Cl⁻ and TDS have contributed most in that order. Therefore, BLIP should upgrade and optimize its treatment plants to increase the removal efficiency for the respective contaminants. Moreover, BLIP should enhance the capacity of the experts through training and continually monitor the quality of the water to protect the environment and ensure its contribution to the building of a resilient city.

Though essential in combating climate change, conserving biodiversity and providing myriad ecosystem services, urban parks in Africa, are challenged by rezoning, encroachment and other pressures. Furthermore, research on urban park tree diversity, dominant species and carbon stocks of parks in developing countries in Africa are scanty. This study assessed the carbon stocks, tree species diversity and stand structure in public parks within Kumasi metropolis. In each selected park, four 40 × 40 m plots were randomly sampled. The heights, diameters, and crown width of all woody vegetation with a diameter at breast height (DBH) greater than 10 cm, were measured and carbon stocks determined. The stand density (p = 0.0546), DBH (p = 0.004), total tree height (p = 0.01), basal area, and carbon stocks (p = 0.018) differed significantly among parks. The carbon stocks of the parks were 80.73 ± 8.77, 45.10 ± 4.83, 76.26 ± 30.19 and 9.59 ± 2.13 MgCha⁻¹ at Kumasi Zoological Garden, KNUST Botanical Garden, Royal Golf Course, and Rattray Park, respectively. With an average of 53.88 ± 11.70 MgCha⁻¹ and 43 species, the public parks in Kumasi have the potential to alleviate climate challenges and conserve biodiversity. The park species composition slightly deviates from the 10/20/30 benchmark stipulated for urban forests. Increasing park tree cover by restoring degraded sections of parks with tree species with high carbon densities, increasing the area and number of parks per city, adopting integrated park management approaches and plans backed by appropriate legislation and policies in cities in Africa could significantly enhance urban climate resilience, conserve biodiversity, and mediate mitigation and adaptation to warmer cities.

Urbanization has resulted in a significant accumulation of waste in densely populated areas. Effective household waste separation practices within urban areas are crucial for advancing the concept of circular economy. The informal system has contributed remarkably to urban material circulation, but it has not been appropriately valued. Through the partnership among the municipal solid waste authorities, condominium building residents, and waste pickers, the latter can be engaged in the community to assist in household waste separation. This initiative would not only enhance their income and reduce probable occupational risks but also augment the recycling rate in the community. Based on the insights from the current waste picker assignment policy in Taichung City, this study has established a mathematical programming model by considering the overall waste separation volume and proximal distance to the neighborhood, facilitating the assignment of individual waste picker to multiple communities within the neighborhood area. Consequently, concerned waste pickers may increase their income and avoid the constraints of picking up recyclables in high-occupational-risk areas. Additionally, it may reduce the volume of unsorted garbage in the community. According to the findings of case studies, the developed model could obtain an optimal solution or acceptable approximate solution in a short timeframe. In contrast to the outcomes from the existing waste picker assignment policy, the application of the developed model could increase the total volume of sorted recyclables, which was directly proportional to the income of waste pickers, by 2.3–2.6 times.

With more than 75% of the European Union’s population living in urban areas covering 21.5% of the EU territory, the importance of climate-resilient cities, towns and suburbs has increased dramatically. However, the rising impact of human-induced land-use changes on ecosystem services (ES) poses a major challenge to the urban environment. This study focuses on scenario development for nature-based solutions (NbS) in a European town with its intense development area. The concept is exemplified in a town in Croatia, Grad Velika Gorica (GVG), that like many others cities undergoes urbanisation processes with limited resources. It serves as a showpiece for the influence of NbS, in particular street trees along various paths.

Using spatial analysis and modelling, the approach explores NbS for future urbanisation. The results, supported by quantitative analysis, show that 49% of cycle lanes and footpaths in GVG can be shaded by strategically planted street trees. The shading scenario analysis provides a nuanced perspective on the potential of NbS, offering insights into the key tasks for a climate-resilient city and opportunities towards equitable, green and healthy urban areas.

In the context of urbanisation processes and climate adaptation, the study is in line with the overarching objectives of the European Commission which emphasises the need for sustainable NbS alternatives to address environmental challenges. The findings contribute to the framework of informed decision-making towards urban climate resilience. It also supports the pursuit of a sustainable local governance for climate-adjusted environmental quality in urban planning. As towns and cities grapple with the imperative of balancing urban development with environmental protection, this research highlights the central role of NbS, particularly street trees, in shaping climate-resilient and more sustainable urban environments for human well-being in cities.

Due to climate change, future weather conditions will become more extreme. During recent years, several severe damages have been caused by heavy rainfalls in combination with riverine events. Even though the effects of compound events are known to be influential for flood hazard, the method for investigating these types of events is a novel area of expertise. In this study, a methodology was developed to investigate a watercourse, acting as a part of a stormwater drainage system in an urban coastal area, in a hydrodynamic model to find areas prone to flooding. The method was applied for Ståstorpsån in Trelleborg, Sweden. The model was a unified model for seasonal variability and compound events with scenarios developed based on series of data representing normal values of the boundary conditions rainfall, river flow and sea level. The result was analysed graphically and statistically as a flood hazard. The data used was based on data collected during the past 10 years for rain and sea level and 16 years of simulated river flow. The constructed rain events from gauge data all had a return time of less than 10 years. Therefore, the chosen events are considered to represent normal levels. For Trelleborg, the results from the hydrodynamic model indicate that compound events will increase the flood hazard with anincreasing time horizon. The visual analysis converges with earlier flood events, and hotspots are generally seen around bridges and culverts. For the studied area, there is a large seasonal variation in the flood hazard and with climate change, all seasons will cause more severe flood hazards. The effects experienced during a summer event, which is the most severe event today, are to be expected for all seasons in 2100. The effect seen during summer eventsis a combination of all three drivers. However, rain intensity is likely to be more influential for normal events. When a certain threshold value for sea level is reached, sea level becomes the most influential driver, overtaking the other drivers in importance.

Understanding and evaluating possible changes in thermal conditions of urban settlements are crucial for risk assessment, adaptation to climate change and sustainable urban development. This study presents the results of a micro-scale measurement campaign conducted in Vienna, Austria, to investigate the effects of natural and artificial surfaces on temperature and humidity variability. The observational data set is used for the evaluation of the newly developed building-resolving urban climate model system PALM. Dragino LHT65 LoRaWAN air temperature and humidity sensors were installed to monitor local-scale variations. On selected summer days, drones equipped with thermal imaging cameras were used to provide hourly surface temperature. The monitoring data show higher temperatures near buildings and overall strong spatial and temporal variations. The model demonstrates the capability to simulate the main thermal characteristics of the study area, although it slightly overestimates temperatures at night. Compared to the measurements, it has a less pronounced spatial variability in air temperature and relative humidity, but a larger one in surface temperature. The analysis confirmed that the urban climate model has the potential to appropriately assess microclimate conditions and therefore, contribute to future-oriented urban planning.

Ecological services in metropolitan areas are degrading more quickly due to changes in LULC brought about by urban expansion. To make a sustainable choice about the ideal location, however, merging the existing simulation approach with LULC optimization approaches involves several intricate procedures. Therefore, the goal of this study is to develop a unique technique that can forecast urban expansion over an extended period and to link with optimization of LULC techniques so as to make meaningful decisions on the impacts of urbanization on loss of biodiversity. In this study, three primary procedures were used: (1) an SVM-based supervised classification technique for LULC classification; (2) a Markov chain and cross-tabulation method for the examination of LULC trends in space and time, (3) utilizing the CA-Markov approach to forecast urban growth. By using Landsat imagery of 2008, 2015, and 2023, the study determined how urban cover changed over time, and what kind of LULC-to-urban transition occurred. The study revealed that uncontrolled and haphazard urban expansion was observed in the Sululta sub-city, which could have disastrous repercussions on physical, biological and urban ecosystem. The %age of urban area increased from 9.04% in 2008 to 13.07% in 2015. However, because of the internally displaced people from the Ethio-Somali Region, who have been resettled there since 2017, the ratio of urban areas grew from 13.7% in 2015 to 24.65% in 2023. Furthermore, by 2040, the sub-city will have grown by 27.69 %. The kappa coefficient statistics of the three classified images of the years 2008, 2015, and 2023 were 93.3 %, 97.5%, and 97.5 %, respectively. To identify the areas that would be covered by future city growth, it is advised that this innovative technique be integrated with optimizing land use strategies.