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Collaboration is strongly promoted as an effective means for cities to respond to climate change. While collaboration is perceived to offer opportunities to progress climate action in cities, little is known about how collaboration can enable low‐carbon transformation in practice. Furthermore, while collaboration is largely framed as a positive endeavour, there is a need to more carefully explore the challenges and barriers that may arise. This paper explores the aims, processes, and outcomes of collaboration within urban climate governance. Drawing on a policy review and semi‐structured interviews, we present empirical findings from the case study of Hong Kong. This paper identifies three types of collaboration that are structured by regulations, oriented to policy goals, and emerge as everyday practices within the governance of climate change and the energy system. The forms of collaboration challenge the assumptions that collaboration always brings positive outcomes in mobilising action for climate change. While collaboration opens up different modes of governance within cities, the paper highlights significant barriers in terms of the diverse roles of actors, ongoing power imbalances, and shifting governance spaces for intervention. Given the prevailing interest in working together, it is critical to review carefully how collaboration facilitates cities to achieve their climate goals and create momentum for action. The paper explores the opportunities and challenges of collaborative climate governance. It draws on a case study of Hong Kong and identifies three modes of collaborative climate and energy governance: regulatory, consensual, and participatory. The paper challenges the assumption that collaboration brings positive outcomes for action on climate change and offers new insights into potential barriers for climate action in cities. [ABSTRACT FROM AUTHOR]

The combined impacts of COVID-19 and global climate change are destabilising the infrastructures and future prospects of formal educational systems, with schools and universities struggling to adapt to conditions of radical precarity. At the same time, activist movements are generating alter-educational platforms that reappropriate the learning infrastructures of cities as mobile architectures of pedagogical resistance. Building on Harney and Moten's The Undercommons, this paper discusses transnational examples of radical pedagogies that engage the city as an ecology of deformalised study. We highlight examples from Melbourne's COVID-19 lockdown regime, emphasising how informal study enabled community-led responses to crisis at city-scale. We then turn to urban ecologies of study arising from contemporary activist movements, drawing connections between protest movements in Hong Kong and Deleuze and Guattari's concept of the 'war machine'. This leads to a speculative re-imagining of alternative educational values and futures within a milieu of activist study, care, and resistance. [ABSTRACT FROM AUTHOR]

• The proposed tropical cyclone model is completely driven by a set of environmental variables. • This model reproduces the spatial and temporal characteristics of observed tropical cyclones. • The model achieves remarkable balance between computational complexity and efficiency. • This model will provide decision-makers with valuable information regarding potential wind-induced hazards. • When future climate data are fed into this model, the impact of climate change on tropical cyclones can be evaluated. This paper presents an environment-driven tropical cyclone (TC) model for the Western North Pacific basin, which comprises a revised Poisson regression genesis model, a tailored beta-advection track model, and a fast intensity model. The TC model reproduces the temporal and spatial distributions of genesis events, the motion pattern of tracks, as well as the intensity evolutions along tracks. Risk analyses for Hong Kong and along the southeast coastline of mainland China demonstrate that this model can simulate extreme TC events with high fidelity. And the Gaussian mixture model outperforms the Frank Copula in approximating the joint distributions of the annual maximum wind speeds and the corresponding wind directions. This model is driven by a set of environmental variables including relative vorticity, relative humidity, sea surface temperature, vertical wind shear, potential intensity, sub mixed layer depth stratification, mixture layer depth and so on. This enables the model to not only reproduce historical records, but also make predictions for future TC behaviors under climate change with combination of global climate models. Besides, the computational efficiency of the TC model is comparable to traditional purely statistical models. The proposed model can also be coupled with other natural hazard models to conduct multi-hazard analysis. [ABSTRACT FROM AUTHOR]

Radiative cooling coating technology is gaining increasing attention in the context of mitigating urban heat island and tackling global climate change. This paper is concerned with the development of an inorganic geopolymer-based radiative cooling coating using red mud, incorporating varying sizes of TiO 2 and hollow glass beads. The developed colored coating demonstrates its radiative cooling capability in reducing the surface temperature by harnessing the potential of red mud. The physico-chemical properties, surface morphology, and element distribution of the coating were characterized by XRD, FTIR, TG-DAT, SEM and EDS. The coating exhibited lower UV (0.0844) and visible reflectance (0.5275) but high NIR reflectance (0.7536), as well as high infrared emissivity of 0.9455, enabling a red color with a CIE value of L* = 74.56, a* = 9.55, and b* = 11.98, and a maximum temperature reduction of 7.3 °C under the climate of Hong Kong. Additionally, the skid resistance, abrasive resistance and adhesion strength of the proposed coating could meet the requirements of standards, indicating a great potential for footway applications. [ABSTRACT FROM AUTHOR]

The combination of dense urban development, hilly terrain, and intense seasonal rainfall has caused acute landslide problems in Hong Kong, which are manifested by a death toll of over 470 people since the late 1940s. Tackling landslide problems in an urban setting, in particular under the effect of climate change, calls for a development and implementation of a holistic risk management strategy. It entails the use of engineering and non-engineering approaches, involving policy, legislative, administrative, innovation, technical, educational, community-based, and emergency-preparedness provisions. In this paper, these two approaches are showcased by the slope safety system that has been developed and promulgated in managing landslide risk for building Hong Kong as a world-class smart city. [ABSTRACT FROM AUTHOR]

Though there has been an increased focus on climate change in Hong Kong's educational policy and curriculum over the last decade, little is known about the impact of curricular implementation on young people's environmental and climate change-related views, attitudes, awareness, or behaviors. This paper examines the state of climate change education in Hong Kong based on findings from a multi-pronged investigation. The main research questions addressed are: (1) what are Hong Kong secondary students’ understandings of and attitudes towards climate change issues? and (2) is there any significant difference between students studying in local and international schools in Hong Kong? The paper provides a content analysis of climate change curriculum in local and international schools. It reports on a large-scale survey of international and local school students’ environmental attitudes, and on qualitative interviews of their awareness and behaviors related to climate change. We conclude with reflections on the implications of this study for climate change education in Hong Kong in the future and vital areas for further research. [ABSTRACT FROM AUTHOR]

Given the climatic and geographical setting, Hong Kong is vulnerable to landslide risk. The poignant history of landslides catalysed the establishment of the Geotechnical Engineering Office (GEO hereafter) in 1977. Since then, a comprehensive Slope Safety System has been formulated and managed by the GEO which has effectively reduced and contained landslide risk through the implementation of multi-pronged risk management strategies. Inheriting the past success, the GEO has maintained a high vigilance of emerging landslide risk and planned ahead for the future enhancement in the System. Extensive studies for the enhancement of emergency preparedness have been conducted with a view to strengthening our capability of managing landslide risk under extreme rainfall. This paper firstly presents the key elements in the Slope Safety System in Hong Kong and then highlights the technical development work in landslide risk management, early warning, landslide emergency system etc., which have been undertaken for improving resilience of the Slope Safety System against extreme rainfall events that are becoming more frequent and intense under the effect of climate change. [ABSTRACT FROM AUTHOR]

Nine engravings in the hinterland around Hong Kong Island have been studied independently by the authors, as part of an overall assessment of current management practices, the state of the engravings, conservation impacts and future survival. Four independent studies were commissioned in 2009 by the Hong Kong Heritage Museum in conjunction with the Antiquities and Monuments Office who have legislative responsibility for all archaeological sites within the Hong Kong Special Administrative Region. The sites have received varying levels of protection in the form of roofs, fences, and screens, and in more recent times, a range of conservation treatments aimed at prolonging their life and improving legibility. This paper reviews the state of the engravings from the point of view of protection and presentation and considers the effectiveness of the infrastructure in mitigating what are often conflicting needs. Modern conservation treatments must be considered in several dimensions: their effectiveness and durability in an aggressive climate, given that the engravings have survived for 3000 years, and the feasibility and cost of maintaining such treatments over the next 3000 years and longer. This paper describes field observations rather than measured data, due to the nature of the commission, highlighting the value of intelligent observation as an investigative tool. The main focus of the paper is on the impact of protective shelters and applied treatments as observed during two of the independent surveys, concluding that protection must address all environmental and visitor impacts to be fully protective. [ABSTRACT FROM AUTHOR]

Cities have increasingly become the focal point for climate change initiatives. However, how cities respond to climate change challenges and through what mechanisms have remained largely unexplored. This paper develops a framework for local governance to examine and explain climate change initiatives in cities. Based on the analysis of 20 climate change initiatives in major cities and a detailed case study of Hong Kong, this paper has two main findings. First, local governments at the city level have an important role to play in climate change policies by embracing some key strategies (such as deliberation and partnership) and values (such as equity and legitimacy) of good governance. Second, by comparing and contrasting the experience in other cities, our case study of Hong Kong provides insights about the barriers that may limit a city's ability to adapt to new forms of governance that would enable it to better respond to climate change. The paper concludes by exploring the potential role of local governance as a model to strengthen climate change initiatives at the city level. [ABSTRACT FROM PUBLISHER]

Carbon emission trading mechanism is an important market-based instrument to address global climate change. The auction ratio and price of carbon emission allowances (CEA) are cores of the carbon emission trading mechanism. What combination of CEA auction ratio and auction price is most conducive to carbon emission reduction for emission control enterprises? There are still relatively few studies conducted on this issue, and there is no clear answer from the views of theory and practice. In this paper, the AIM/Enduse model was used to analyze the changes and differences of installed power capacity, power supply, energy consumption and carbon emissions in the Guangdong-Hong Kong-Macao Great Bay Area (GBA) with different combinations of CEA auction ratios and prices. Moreover, the best pathway of energy transition was explored in the power industry of the GBA, and the best combination of CEA auction ratios and prices was identified in the GBA. The results show that: (1)The carbon emission constraint starts to work only when the auction ratio of CEA is increased to 50% and the auction price is increased to 60 CNY/ton (Scenario p 3). When the auction ratio of CEA is 100% and the auction price reaches 120 CNY/ton (Scenario p 5), a low-carbon transition of the power sector in the GBA can be achieved. (2) Under scenario p 5 , the total cost of power transition rises and then falls. And the cost of carbon in the power sector increases exponentially as the auction ratio of CEA and the auction price rise. However, the growth in the cost of power supply is relatively flat, which shows that appropriate carbon trading mechanism can improve the economic benefits of power sectors. With the increase of installed capacity of clean low-carbon energy generation and power supply, as well as the decrease of local power cost in the GBA, the proportion of outsourcing power can be appropriately reduced in the future, with an aim to reduce the external dependence of electricity to ensure the security of energy supply. In the end, it suggests that cities in the GBA should give full play to their regional advantages and establish a unified carbon emission trading market in the GBA as soon as possible. This study provides a theoretical basis for the supplementation and improvement of China's carbon emission trading mechanism. • What is the best combinations of CEA auction ratios and auction prices in the GBA? This paper gives a clear answer. • The best transition pathway of the power industry under technological progress and carbon trading policy was suggested. • With the decrease of local power cost, the proportion of outsourcing power can be appropriately reduced in the future. • Provides a theoretical basis for the supplementation and improvement of China's carbon emission trading mechanism. [ABSTRACT FROM AUTHOR]

• A multi-model and multi-method ensemble approach for wind resource projection is proposed. • Future wind potential in Hong Kong is assessed for the first time. • Robustness of the climate change signal is evaluated. • An increase in wind power density during summer (+23.7 %) and a decrease during autumn (–15.1 %) in 2081–2100 are projected for SSP5-8.5. Harvesting renewable wind energy is among the most cost-efficient means of reducing carbon emissions and achieving carbon neutrality. However, wind resource is susceptible to climate change impacts since the global temperature increase will reshape atmospheric circulation patterns. To facilitate the evaluation of fine-scale wind energy potential under climate variability, this paper proposes and validates a multi-model and multi-method ensemble wind resource projection approach. Then this approach is utilized to investigate the future variation of wind resources in Hong Kong based on the combined use of global climate models from Coupled Model Intercomparison Project Phase 6 and long-term observations from meteorological stations. It is found that there is a significant increase in future wind resources during summer, while a remarkable decline is projected during autumn. Nevertheless, the variations of wind resources in winter and spring are relatively insignificant. The outcomes of this study are expected to offer a framework for fine-scale wind resource assessment under climate change, and facilitate the economic and risk assessments of future wind farm projects. [ABSTRACT FROM AUTHOR]

The paper studies the horizontal global, direct-beam and sky-diffuse solar irradiance data measured in Hong Kong from 2008 to 2013. A machine learning algorithm was employed to predict the horizontal sky-diffuse irradiance and conduct sensitivity analysis for the meteorological variables. Apart from the clearness index (horizontal global/extra atmospheric solar irradiance), we found that predictors including solar altitude, air temperature, cloud cover and visibility are also important in predicting the diffuse component. The mean absolute error ( MAE ) of the logistic regression using the aforementioned predictors was less than 21.5 W/m 2 and 30 W/m 2 for Hong Kong and Denver, USA, respectively. With the systematic recording of the five variables for more than 35 years, the proposed model would be appropriate to estimate of long-term diffuse solar radiation, study climate change and develope typical meteorological year in Hong Kong and places with similar climates. [ABSTRACT FROM AUTHOR]

Under the Kyoto Protocol's Clean Development Mechanism (CDM), countries worldwide co-operate on encountering climate change by emissions trading, which enables a win–win situation by effectively “regenerating” a cleaner environment in developing countries, whilst efforts in developed countries may still not meet their committed targets of carbon reduction. According to the CDM rules, energy efficiency improvement projects in the building sector are valid for emissions trading. Although the potential saving of energy is significant, there is only a limited number of building projects being registered as CDM projects. This paper explores the applicability of CDM in the building sector by reviewing the implementation of CDM and its advantages and disadvantages. Hong Kong was selected for an in-depth study due to its eligibility for CDM and yet non-starter status. According to a questionnaire survey supplemented by interviews with the stakeholders in this study, major hindrances such as the lack of financial incentive, inadequate knowledge about emissions trading and insufficient governmental support were found in potential CDM projects in the building sector. It is recommended that an inter-city emissions trading market covering mainland China and Hong Kong, and suitable emission reduction targets should be established and led by the government at the initial stage. By setting up an emission exchange centre, local emissions trading activities could be facilitated and job opportunities could be created. In addition to conducting emissions trading, Hong Kong may also contribute to emissions trading in the region by making use of its highly skilled professional services and efficient business environment. This study paves the way for a densely built city such as Hong Kong to benefit environmentally and economically from a cleaner region in its vicinity. [ABSTRACT FROM AUTHOR]

ABSTRACT Heavy rain events or rainstorms of various scales often occur in Hong Kong from April to September. In extremes cases, they lead to serious landslides and flash floods resulting in loss of life, and damage to property and infrastructure. With climate change, extreme rain events are projected to be more frequent and more intense in this region. A system to gauge and label the severity of rainstorms would be useful for identifying and communicating extreme conditions in warning and disaster prevention operations. In parallel, a better understanding of the characteristics of rainstorms would also be important for impact assessments and engineering design purposes. This paper formulates a practical framework to index the magnitude and severity of rainstorms in Hong Kong. An index termed as the Severity Index combining the magnitude of different rainstorm attributes is devised for quantifying the overall severity of rainstorms. This index is flexible to allow tuning for specific applications. [ABSTRACT FROM AUTHOR]

• Economic drivers and barriers were identified to be most significant for ZCB in HK. • User behavior changes can have a major impact on ZCB delivery in HK. • Four strategy areas most address ZCB complexities and dynamics in high-density cities. • ZCB requires micro-level measures, meso -level initiatives and macro-level visions. • A novel multi-level framework of strategies is derived for high-rise high-density ZCB. The zero carbon building (ZCB) approach has been adopted in many cities and regions as an important government strategy for addressing climate change, achieving a low carbon economy, and uplifting the quality of people's life. However, there is yet a lack of uptake of ZCB in high-rise high-density contexts, and mystery exists about its feasibility and societal acceptance. This paper aims to demystify ZCB development in high-rise high-density cities by identifying and examining the drivers, barriers and strategies within Hong Kong as a typical case. Based on the systems theory that addresses ZCBs as complex systems, the research was conducted through a questionnaire survey with 219 effective responses from and six follow-up focus group meetings with industry stakeholders. Key drivers and barriers were systematically identified, covering economic, legislative, cultural, supply chain, geographical, and skill and knowledge aspects. Specifically, economic drivers and barriers were found most significant. A novel multi-level framework of strategies was further derived, integrating micro-level measures, meso -level initiatives and macro-level visions for achieving ZCBs in high-rise high-density cities. The framework contributes a new perspective to examine ZCB drivers and barriers, and lays the foundation for a strategic decision-making tool to support ZCB developments. [ABSTRACT FROM AUTHOR]

• In-situ monitoring allows for a more reliable estimation of envelope performance of residential buildings. • Policy differences are one of the main causes for the variation in building envelope performance across regions. • Potential global warming impacts ought to be considered when pondering on the future direction of envelope development of residential buildings. • Interactive policy framework underscores the necessity of devising more comprehensive public policies pertaining to energy saving. Climatic conditions can exert significant impacts on energy demand of residential buildings. Therefore, case-based evidence is necessary for aiding local policy making on building energy performance. By designing and carrying out in-situ monitoring campaigns respectively in Cambridge, Hong Kong and Shanghai, we present in this paper a cross-regional analysis of actual building envelope performance in these three climatic regions that operate under different energy efficiency policies. Compared with conventional tabulated data, information gleaned from the method of in-situ monitoring shows lower uncertainty and higher precision, especially when the wall has good thermal properties. By comparing practices in different regions and with accurate post-occupancy thermal data, the analytical results further show that the effectiveness of building-related policies on energy performance varies across regions. This is one of the pioneering studies that make interactive policy recommendations based on the evidence obtained from cross-regional, in-situ monitoring campaigns. [ABSTRACT FROM AUTHOR]

• Building Bio-Climatic Charts are proposed for different climate change scenarios. • Time-varying significance of nine design parameters in this century are provided. • Effectiveness of airtightness will increase up to 329% by the end of this century. • Cooling potentials of natural ventilation will significantly decrease up to 69%. • A holistic passive design can reduce the building annual cooling load by 56.7%. The application of passive design strategies is crucial at the early architectural design stage for building energy use minimization. However, the time-varying effectiveness of passive design strategies in responding to future climate change in hot and humid climates are rather limited in the literature. This paper aims to examine the dynamic effectiveness of passive design strategies for residential buildings in Hong Kong under the context of future climate change. Using the newly developed hourly weather data and adaptive comfort standard model, the dynamic effectiveness of viable passive design strategies for residential buildings are evaluated over time in the 21st century by plotting Givoni building bio-climatic charts (BBCC) and simulation-based sensitivity analyses in a validated EnergyPlus model. Results show that solar protection strategies are still the highly sensitive strategies for building energy performance and the effectiveness of external windows' airtightness is expected to increase up to 329% by the end of this century, whereas the cooling potential of ventilation utilization will significantly decrease over time. When the different combination of sensitive passive design parameters is implemented onto the baseline residential building model for different climate scenarios, the annual and peak cooling load can be reduced up to 56.7% and 64.5%, respectively. [ABSTRACT FROM AUTHOR]

• The climate change is identified by the ground measurement of HK over the 37 years. • The building energy needs can be influenced by the climate change. • The TMY is suggested to be updated every 10 years or less for the climate change. • 10 to 12 years of the latest data can be proper for TMY in the changing climate. The weather data is essential to simulation-based building energy studies. The weather data should render the features of the changing climate. The typical meteorological year (TMY) developments using the long-term climate data, however, may weaken the impact of the recent climate change and the corresponding building energy responses. This paper studies the changes of the climate data (by ground measurements) and their impacts on the simulation results of the subtropical Hong Kong over 37 years. The climate changes for solar radiation, temperature and wind speed were summarised, and their daily total, average, extreme, and/or deviation values were presented. The typical weather data developed by the ground measurements of different times and period lengths (within the 37 years) determined the cooling load of a representative building in the Hong Kong, and the outcomes were compared to that of the yearly data. The period (length) of the raw measurements and the update frequency of TMY were optimized for the building energy simulations in the changing climate. [ABSTRACT FROM AUTHOR]

• A spatial-temporal rain field generator is developed to reproduce regional rainfalls. • The generator produces likely future rainstorm scenarios considering climate change. • Correlations among temporal process parameters and different stations are considered. • Rain extremes may increase notably at the end of 21st century in Greater Bay Area. A stochastic rainfall generator is required to provide rainfall inputs for the analysis and mitigation of such hydrological or geologic hazards as floods and rain-induced landslides. This paper presents a new spatial-temporal rainstorm generator for generating simultaneous rainfall processes at numerous locations considering the spatial correlation among these locations and interpolating the point processes into an areal rain field. The generator is able to include the effect of climate change by adjusting the parameters of the marginal distributions of variables constituting rainfall events. A case study on the Guangdong-Hong Kong-Macau Greater Bay Area (GBA), one of the regions that are most prone to storm-related disasters in the world, is presented. The performance of the proposed generator is excellent in reproducing the historical statistical characteristics of regional rainfall. The model is adapted to climate change through extrapolation of the variation trend of the model parameters in the observation period to explore possible future scenarios of regional rainfall in GBA. The simulation results indicate a significant increase in rainfall extremes, especially for short-duration rainfall, at the end of 21st century in GBA. [ABSTRACT FROM AUTHOR]