Utilization of urban green vegetation (UGV) has been recognized as a promising option to mitigate urban heat island (UHI) effect. While we still lack understanding of the contributions of local ...background climate to the cooling effect of UGV. Here we proposed and employed a cooling effect framework and selected eight typical cities located in Temperate Monsoon Climate (TMC) and Mediterranean Climate (MC) demonstrate that local climate condition largely affects the cooling effect of UGV. Specifically, we found increasing (artificial) rainfall and irrigation contribute to improving the cooling intensity of grassland in both climates, particularly in the hot-dry environment. The cities with high relative humidity would restrict the cooling effect of UGV. Increasing wind speed would significantly enhance the tree-covered while weakening the grass-covered UGVs' cooling effect in MC cities. We also identified that, in order to achieve the most effective cooling with the smallest sized tree-covered UGV, the area of trees in both climate zones' cities should generally be planned around 0.5 ha. The method and results enhance understanding of the cooling effect of UGVs on larger (climate) scales and provide important insights for UGV planning and management.
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•The cooling effect of urban blue-green space and threshold-size-based studies are reviewed.•The controversies and uncertainties on the cooling effect of urban blue-green space are ...revealed.•The basic framework and perspective of the urban cooling effect studies are proposed.•The new technology and method for furthering urban cooling effect studies are suggested.•The implications of the threshold-size of blue-green space for actionable climate adaption planning are discussed.
The cooling effect of blue-green space has been recognized as a promising approach to mitigate the urban heat island (UHI), while the quantitative role (threshold-size for cooling) is still uncertain. This paper aims to present the latest progress and controversies on the studies of the cooling effects of waterbodies, greenspaces, and parks. In order to do this research, international search engines were employed to systematically search peer-reviewed articles, including the cooling effect of blue-green space and threshold-size-based UHI mitigation studies. After that, the inductive analysis is used to analyze the relevant literature. We found that previous studies concentrated on the correlations between different landscape types, temperature variations and the quantification of cooling intensity, etc. However, threshold-size-based research has received less attention, which limits the ability to make specific recommendations for actionable planning and management – usingthe smallest blue-green space for the best cooling effect. The review also revealed the controversies over the effects of blue-green space size, shape, landscape composition and configuration on cooling effect. Besides, we pointed out that the uncertainties (i.e., the optimal proportion of blue-green space in a park) and the reasons of controversial results of the cooling effect need to be further investigated. We also suggested that more attention should be paid to quantify the contributions of local background climate and landscape characteristics to the cooling effect (threshold-size) of blue-green space. This review would give us a deeper understanding of the field and provide insights into actionable climate adaption planning.
Contexts
Urban green infrastructure (UGI) has been recognized as a promising approach to mitigating urban heat island (UHI); however, most of the previous studies are case-based and explore the ...effects of the existent landscape and its spatial configuration on UHI mitigation rather than modeling an optimized spatial pattern.
Objectives
We aimed to transcend the existing research logic (from case studies to obtain the patterns of the cooling effect of UGI, then propose implications for UHI mitigation) and established a hypothetical idealized urban thermal security pattern model (TSP
urban
).
Methods
Based on two basic concepts deduced from the physical property of UGI—(threshold) size and cooling distance, as well as the simplifying assumptions we defined. Then, three proposed conceptual UGI types (ecological, efficient, and elementary—3E) and subtypes were used to frame the model.
Results
We deduced that the idealized TSP
urban
model conforms to a hierarchical hexagonal structure in theory and it can be calculated and applied, although it generally cannot be seen in the real world.
Conclusions
The idealized TSP
urban
model can help us better-understanding UGI cooling effects when considering climate adaption planning and decision-making; it also serves as a novel pathway to study the cooling effects of UGI and mitigate the UHI effect.
Due to deindustrialisation, young industrial landscapes (YILs), stemming roughly from the 1930s to the 1970s and located in the suburbs of Copenhagen, are partly abandoned, partly in use, and partly ...used for non-industrial purposes. By virtue of their location, size, and unused and underused subareas, YILs can potentially meet major urbanisation aims, such as densification and mixed-use development, yet the redevelopment of YILs often happens from a hypothetical virgin land position, disregarding the existing features of these sites. In this paper, we aim to introduce value-sustaining strategies for a more site-informed transformation of YILs. The specific objective is to investigate and understand the landscape-based transformation of young industrial landscapes by making explicit use of their site features in what we label the landscape. Based on a literature study of the emerging phenomenon, a screening of landscape-based projects and a case study, we present a set of qualifying strategies to guide future landscape-based transformations: porosity, reuse, re-naturing, and open-endedness. The complimentary spatial, multi-scalar, and temporal strategies were demonstrated through the study of the five European cases: Alter Flugplatz Kalbach, Hersted Industripark, IBA Emscher Park, Louvre Lens Museum Park, and Parc aux Angéliques, to exemplify how the strategies could guide the landscape-based transformation of YILs or similar types of large-scale landscapes. Although apparently straight forward, the formulation of the four strategies linking ethics and transformation practices provides a much needed set of values and tools in the current, and also historical, redevelopment of YILs, which are a significant part of our urbanised landscapes, to better address societal challenges.
This article traces the development process of Beijing’s First Green Belt from its origins in the 1950s, to its reinterpretation in the 1980s/1990s and its implementation in the 1990s/2000s. We ...identify three-time phases and important milestones, which kept the green belt idea alive, developed it and contextualized it in relation to the historical background. This article shows that the first green belt project in Beijing was a continuing process of changing functions and ranges. Its adaptability to variations followed the political changes and reflected the socio-economic dynamics, which secured its longevity. Different ideas shaped the plan and its link to mega events like the Olympic Games and environmental problems accelerated the implementation, but the shortage of funding and absence of legislation led to a compromised result. The case is an interesting example of how a long-term project transforms over and with time, but also for the gap between planning ambitions and actual urban development, illustrating past and contemporary urban planning in the context of a fast-developing country.
•The most accurate algorithms with which to retrieve land surface temperature in subtropical city is assessed.•The concepts of cooling extent, intensity, and efficiency of green space are defined and ...calculated.•The influences of the size and shape of green spaces on cooling the city and on climate adaptive design are shown.•The UCI effect is dependent on different types of green space, including internal composition and external configuration characteristics.•The methodology can be used in other cities to achieve sustainable and climate adaptive planning.
The cooling effect of greenspaces is an important ecosystem service, essential for mitigating the urban heat island (UHI) effect and thus increasing urban resilience to climate change. Techniques based on landscape planning to alleviate the increasing frequency of extreme climate are becoming more of a focus in urban ecology studies. In this paper, we proposed and defined the urban cooling island (UCI) extent, intensity, and efficiency, as well as the threshold value of efficiency (TVoE) introduced from the “law of diminishing marginal utility” for the first time. The radiative transfer equation has been compared with other algorithms and used to retrieve accurate land surface temperature (LST) in a subtropical city of China − Fuzhou. Two important and arguable factor − size and shape of greenspaces also been expressed and explored. The results indicate that: (1) larger-sized greenspaces produce a higher cooling effect. However, there exist a TVoE, which is in line with our hypothesis. The TVoE in Fuzhou is 4.55ha. (2) The circles and squares greenspaces have a significant correlation with LST and also show the highest UCI intensity and efficiency. (3) 92% of the maximum extent of greenspaces are within the 30–180m limit, and the mean UCI extent and intensity are 104m and 1.78°C. (4) The greenspaces connected with waterbodies intensified the UCI effects, whereas the grassland-based greenspace shows the weakest UCI effects. The methodology and results of this study could help urban planners to mitigate the UHI effects efficiently, and to employ the climate adaptive planning.
•A year-round analysis was conduct regarding the cooling extent, intensity, and efficiency of blue-green space.•The concept of the threshold value of efficiency (TVoE) was validated and calculated in ...different seasons.•The effect of temperature on TVoE was revealed, which deepens the understanding of the TVoE study.•The roles of blue and green (tree- and grass-covered) space on cooling effect in a high latitude city were analyzed.•The climate adaptive planning implications in high latitude cities were suggested.
Climate change has increased the frequency of extreme climatic events and the intensity of heatwaves in high-latitude cities that have rarely been affected in the past, yet there is less attention to these regions. Therefore, we selected Copenhagen as the case, we used spatial/statistical methods to assess the cooling-effect of blue-green spaces in different seasons. We found (1) land surface temperature (LST) is negatively correlated with Normalized Difference Vegetation Index (NDVI) and Modified Normalized Difference Water Index (MNDWI) in all seasons; (2) Tree-covered greenspace with a compact shape would be a priority for climate adaption in high-latitude cities. While when the area of blue-green space is large to a certain extent (>1 ha), the complex shape also has a strong cooling-effect. Further, the area and cooling extent and intensity conform a logarithm function with significant correlations except for winter. (3) Compared with other seasons, blue-green space provides a higher cooling-effect in summer, and the mean cooling extent and intensity are 150 m and 2.47℃; (4) Background temperature can significantly affect the threshold value of efficiency (TVoE). The results of this study expand the understanding of the cooling-effect of blue-green spaces and provide implications for sustainable urban planning.
In this paper, we develop and apply a multi-dimensional vulnerability assessment framework for understanding the impacts of climate change-induced hazards in Sub-Saharan African cities. The research ...was carried out within the European/African FP7 project CLimate change and Urban Vulnerability in Africa, which investigated climate change-induced risks, assessed vulnerability and proposed policy initiatives in five African cities. Dar es Salaam (Tanzania) was used as a main case with a particular focus on urban flooding. The multi-dimensional assessment covered the physical, institutional, attitudinal and asset factors influencing urban vulnerability. Multiple methods were applied to cover the full range of vulnerabilities and to identify potential response strategies, including: model-based forecasts, spatial analyses, document studies, interviews and stakeholder workshops. We demonstrate the potential of the approach to assessing several dimensions of vulnerability and illustrate the complexity of urban vulnerability at different scales: households (e.g., lacking assets); communities (e.g., situated in low-lying areas, lacking urban services and green areas); and entire cities (e.g., facing encroachment on green and flood-prone land). Scenario modeling suggests that vulnerability will continue to increase strongly due to the expected loss of agricultural land at the urban fringes and loss of green space within the city. However, weak institutional commitment and capacity limit the potential for strategic coordination and action. To better adapt to urban flooding and thereby reduce vulnerability and build resilience, we suggest working across dimensions and scales, integrating climate change issues in city-level plans and strategies and enabling local actions to initiate a ‘learning-by-doing’ process of adaptation.
This paper investigates and broadens the discussion of nature-based climate adaptation for storm water management and coastal flooding. Based on three Copenhagen cases of locally initiated innovative ...flagship projects and framed by governance and transition theory, we investigate how nature-based solutions can be understood in a real-life context, and how hybrid projects joining technical and nature-based solutions might work; the governance methods of such projects; and their transitional potential. The cases underscore the importance of nature perception for the design of the project, and the role of daily recreational users as crucial for project legitimacy. Innovative projects might seem local, but often they are embedded in larger strategies and serve to flesh out such strategies and might even change them in a longer perspective. New problems and projects foster a need for new types of partnerships, which can challenge co-operation. Finally, it is questioned how – and if – experiences from flagship projects can be anchored and mainstreamed into a new normal for climate adaptation.
Public spaces, by their physical environment design, are intended to be accessible to all and significantly contribute to children's development. Existing research on the inclusion of children often ...overlooks the influence of the public spaces' physical environment. Hence, the understanding of how children's public life is spatially integrated into public spaces is insufficient. This article explores the spatial potential of the physical environment to include children within broader public life in urban public spaces. It aims to suggest an analytical framework, termed spatial inclusiveness, for examining or prescribing the spatial inclusion of children in public spaces. This was done by mapping the spatial characteristics of 148 public spaces with public playgrounds in Copenhagen, Denmark. It resulted in 16 categories grouped into five parameters, which involve diverse spatial characteristics describing different degrees of spatial connection and visual connection between public playgrounds and their adjacent public spaces. By elaborating on the relationship between the physical environment and their spatial potential for including playing children, the framework strives to capture connections between urban regeneration's physical and social dimensions. The framework provides urban designers, planners, and city authorities insight into improving the inclusion of public spaces from a spatial perspective with guidance and recommendations.
•The dedicated playgrounds foster the exclusion of children from broader public life.•Social inclusion can be promoted through urban design and planning in public spaces.•Spatial inclusiveness describes spatial potential for social inclusion.•Spatial inclusiveness includes spatial connection and visual connection.•Spatial inclusiveness improves social inclusion from a spatial perspective.
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