Urbanization has been identified as one of the most important strategies for development in the 21st century [1
]. According to the World Bank [2
], the ratio of urban populations at a global level has already exceeded 50% in 2007 and this will continue to rise in the coming decades according to the theory of Northam’s “S” curve [3
]. Urbanization has been commonly recognized as producing many benefits, such as job opportunities, health facilities, infrastructure services, income increase, etc. [4
]. However, it has been widely reported that the unprecedented rate of urbanization over the last few decades throughout the world has posed various drawbacks such as climate change, flood, loss of arable land, and pollution of natural resources [6
]. For example, the research by Shen et al. [11
] pointed out that during the recent urbanization process in China, more than 2 million farmers per year lost their farmland. There are still other problems brought about by improper urbanization. Schultz [12
] and Swan [13
] opined that the rapid urbanization process has induced serious flooding problems, especially in emerging countries. Dewan & Yamaguchi [14
] investigated the relationship between rapid urban growth and flood disasters in Bangladesh, and concluded that urbanization has a significant association with flooding. Furthermore, Dewan et al. [15
] developed a flood hazard map to reduce potential flood damage, and presented general flood hazard management strategies such as planning low development densities and strength drainage facilities, etc.
Urgent action is required to develop sustainable urbanization practices in order to address these challenges [18
]. In line with this development, governments and various non-governmental organizations (NGOs) throughout the world have been increasingly introducing measures to guide the practices of urbanization towards better sustainability. Typical programs introduced for engaging sustainable practice during urbanization programs include the Urban Management Program of UN-Habitat [20
], the UN’s Millennium Declaration [21
], the Istanbul Declaration of the North Atlantic Treaty Organization (NATO) [22
], the Hong Kong Planning Department’s HK2030 Study [23
], Melbourne City Council’s City plan 2010 [24
], the government of Singapore’s Green Plan [25
], the government of Mexico City’s Plan Verde [26
], and Iskandar Development Region’s Comprehensive Development Plan approved by the government of Malaysia [27
]. The promotion of sustainable urbanization in previous years has led to many positive experiences, and it is considered that sharing and learning best practice between different countries can make significant contributions to the global mission of sustainable urbanization [28
]. In order to share experiences of sustainable urbanization, there is a need for properly evaluating the performance of the implemented urbanization practices and identifying best practice. Other studies have also appreciated the importance of the evaluation of sustainability performance in order to identify weaknesses and problems in the practice of urbanization so that proper correction can be made [29
In recent years, there has been significant development of methods, techniques, and tools for assessing sustainable performance during the urbanization process. Zhang [30
] proposed a bi-dimensional matrix model to analyze the performance of environmental, social, and economic dimensions at different stages of urbanization. Shen et al. [31
] established an elasticity coefficient model for capturing the dynamic nature of the urbanization process by employing two parameters, namely urbanization velocity (VµR) and sustainable urbanization velocity (VµS). Mori and Yamashita [32
] presented a framework of City Sustainability Index (CSI) for assessing the sustainability performance of urbanization, where the indicators are selected across environmental, economic, and social dimensions to assess the performance of sustainable urbanization. Dewan and Corner [33
] presented a way of using of remote sensing technology for estimating urban sprawl, growth, and urban structures. Xu and Coors [34
] employed the techniques of Geographic Information System (GIS) and 3D visualization to assess the performance of urban development. Among these typical methods, it appears that the indicator-based approach is most commonly adopted to assess the performance of urbanization against goals and targets [35
]. A report by the United Nations [36
] suggests that indicator-based methods can help provide early warnings and effective information to prevent setbacks by taking measures in advance. The study by Ramos and Caeiro [37
] opined that indicator-based methods can increase the accuracy of evaluation of the sustainable performance of urbanization. In agreement with this, Hiremath et al. [28
] suggested that indicator-based methods can help demonstrate how well urbanization is implemented towards sustainable practice. Based on the above discussion, the indicator-based evaluation method is therefore adopted in this study to assess the sustainable urbanization performance from a global perspective.
There are various domains in examining sustainable urbanization; these apply different sets of indicators. For instance, Shen et al. [38
] assessed the utility efficiency of metro infrastructure projects (MIP) in China from the perspective of sustainability performance by using five key indicator:, Population of city (POP), length of Metro systems (LEN), annual ridership of Metro systems (RID), ticket price (FAR), and gross domestic product (GDP). Weber and Puissant [39
] examined the performance of sustainable development of Tunis Metropolitan Area by incorporating the land cover indicators. Dewan et al. [40
] assessed the effect of urban expansion in Greater Dhaka on the promotion of sustainable urbanization. Weiland et al. [41
] presented an indicator system for assessing the performance of sustainable land use in the process of urbanization in Santiago, Chile. Zhang et al. [42
] established a quantitative model composed of 19 indicators for evaluating the efficiency of the urban infrastructure from the perspective of sustainable development.
Existing studies have also addressed ways of assessing sustainable performance of urbanization at national, regional, and local levels. For example, Shen and Zhou [1
] examined the effectiveness of nine indicator-based systems introduced by the Chinese government, and revealed that the existing indicator systems have limitations when guiding sustainable urbanization in China. Hernández-Moreno and Hoyos-Martínez [43
] assessed the sustainable performance of urbanization in Mexico City. Yigitcanlar et al. [44
] introduced a multi-scalar indicator system to evaluate sustainable urbanization performance in Gold Coast, Australia. By using remotely sensed data collected with the assistance of GIS, Dewan et al. [45
] analyzed the landscape fragmentation in Bangladesh for the period 1975–2005. Jensen [46
] demonstrated the sustainability profiles between the districts in Copenhagen city by using a model composed of 20 main indicators across environmental, social, and environmental dimensions. Reddy and Balachandra [47
] investigated the sustainable performance of urbanization development in India by using an indicator-based evaluation approach. Byomkesh et al. [48
] evaluated the performance of urban green space in Bangladesh by employing a set of indicators.
The above suggests that while many studies have assessed the sustainable performance of urbanization at the national, regional, and local level, there is no study examining it from a global perspective. It is therefore the aim of this study to assess the sustainable performance of urbanization at a global level. In pursuing this research aim, focus is given to the sustainability performance of urbanization at a national level rather than an urban level, as performance at the urban level is unable to reflect the sustainable urbanization performance of a whole country. This study evaluates the sustainable performance of urbanization in 111 countries for which the relevant data for analysis are available from the World Bank and United Nations, etc. The reminder of the paper is organized as follows. Section 2
introduces methods of indicator selection, weighting establishment, and sustainable urbanization evaluation. Section 3
establishes the comprehensive and international indicator system, which can assess sustainable urbanization performance at the global level. Section 4
presents the evaluation results and a ranking list of sustainable urbanization performance across 111 countries. Section 5
discusses the evaluation results of sustainable urbanization performance from the performance ranking and global perspective, and further investigates the relationship between the urbanization process and sustainable urbanization performance. Finally, Section 6
summarizes the main findings of this research.
This paper measures the sustainable urbanization performance from a global perspective. The results suggest that the best performers in terms of overall sustainable urbanization during the surveyed period are Sweden, Norway, Germany, the Netherlands, and Denmark. The best performers are mainly developed countries in Europe. Other good performers include Brazil, Romania, and Thailand. Poor performers are mainly distributed in Africa and Asia. The regression analysis in the study suggests that there is a negative correlation between urbanization rate and sustainable performance when urbanization is at the initial stage, and a positive correlation when urbanization is at the acceleration stage. There is no significant correlation between urbanization rate and sustainable performance if the urbanization is completed.
The two major take-home messages of this study can be summarized as follows. Firstly, it is imperative to pursue development that is balanced between economic, environmental, and social dimensions in order to achieve better sustainability performance during the urbanization process. Many countries with poor sustainable performance are found to be interested in only one dimension and not giving sufficient attention to the others. Take China as an example: its urbanization is typically economy-driven, giving less attention to environmental protection. Secondly, it is important to share best practice in sustainable urbanization between various countries. In general, developed countries perform better on sustainable performance than developing countries. Sharing these good experiences particularly among less developed countries will make effective contributions to the global mission of sustainable development. In this context, developed countries can assist poor-performing countries by sharing knowledge and management skills in the process of urbanization. In future studies, this research team will investigate mechanisms for effectively promoting experience-sharing in practicing sustainable urbanization between different countries.