1. Introduction
With the gradual acceleration of global urbanization, large-scale population aggregation has brought vitality to the development of cities. However, it has also significantly increased the pressure on various cities’ infrastructures. The capability of infrastructure is complex to match the population’s needs, which has brought a series of potential crises to rapidly developing cities [
1]. At the same time, due to the environmental damage caused by modern human activities, extreme weather has occurred frequently. For example, Henan Province in China was hit by a hefty rainstorm in July 2021, which affected 14.78 million people. The negative consequences caused by rapid urbanization and frequent natural disasters seriously hinder the normal development of cities, directly promoting urban resilience research [
2]. Some scholars pointed out that the different abilities of cities to cope with external risks stem from the difference in their resilience [
3]. Resilience refers to the ability of a system to absorb risks to the maximum extent, maintain its original functional stability, and gradually adapt to risks when facing external shocks [
4]. The higher the level of resilience, the greater the system’s ability to resist external disturbances. The United Nations Human Settlements Programme pointed out that urban resilience construction should be a critical global agenda [
5]. Therefore, measuring urban resilience is significant for promoting high-quality urban development.
Meanwhile, cities with populations exceeding 1 million or even 10 million have gradually emerged worldwide. For example, Tokyo is one of the world’s most populous and urbanized cities, reaching about 38 million people in 2022 [
6]. New Delhi, Shanghai, and São Paulo are mega cities with populations of over 20 million people. By the end of 2020, there were 532 cities worldwide with a population of over one million. The Chinese government defined a large city as one with a permanent population of over 1 million people in urban areas. By 2022, China already had 105 large cities. Compared with ordinary cities, large cities are usually the central cities within a specific area, with a larger population and more important political and economic status. Various complex urban activities and the interaction between cities are becoming increasingly frequent, increasing the importance of large cities daily. However, the inability of infrastructure to meet the population’s needs and the increasing environmental damage have brought various pressures to the resilience of large cities. Therefore, it is necessary to accelerate the research on the resilience of large cities to improve their stability. Some scholars have noticed this issue and begun to explore the urban planning [
7] and disaster resistance capabilities [
8] of some large cities.
Resilience was initially applied in engineering to describe the stability of materials and their performance in restoring their original state under external forces [
9]. Recently, resilience theories have been applied in urban research. Scholars have engaged in heated discussions on the connotation of urban resilience [
10]. For example, Zhang et al. [
11] define urban resilience as the ability of urban systems to cope with uncertainties such as external disturbances or long-term changes, emphasizing the self-organizing processes of cities in the face of disasters, including absorbing losses and gradually adapting to risks. Vargas et al. [
12] define urban resilience as the ability of the social ecosystem extended by a city to maintain essential structural functions in the event of disturbances.
In order to better determine the ability of cities to cope with external risks and more accurately evaluate the level of urban resilience, scholars have conducted studies on establishing an evaluation index system for urban resilience. The overall impact of urban subsystems such as the economy, society, and infrastructure [
13] on urban resilience is mainly based on urban characteristics and elements. For example, Xun et al. [
14] constructed an urban resilience evaluation index system based on dimensions such as economy, society, ecological environment, and municipal facilities. Some studies analyze the resilience process in response to external risks in cities, including the stages of pre-disaster warning, disaster resistance, post-disaster recovery, and adaptation that cities experience when disasters invade cities [
15]. Selecting indicators based on urban behaviors at different stages can more accurately reflect the role of urban resilience in risk impact. For example, Zhang et al. [
16] developed a comprehensive flood resilience assessment framework based on the pressure–state–response (PSR) model, which can systematically evaluate the performance of cities in flood disasters. Ji et al. [
17] applied the PSR model to study the resilience of floods from the pressure caused by disaster factors to the urban state during disasters and then to the post-disaster urban recovery and resilience improvement.
Resilience evaluation mainly relies on various quantitative evaluation methods. Most studies adopt a comprehensive weighting method that combines weighting and quantitative analysis [
18]. For example, Moghadas et al. [
19] applied the analytic hierarchy process (AHP) and technique for order preference by similarity to an ideal solution (TOPSIS) model to evaluate Tehran, Iran’s flood disaster resistance capacity. This method is limited to relying on a subjective weighting process. Therefore, objective weights such as the entropy weighting method are often used to avoid subjective errors. Zhou et al. [
20] comprehensively applied the TOPSIS, entropy weight method, and coupling coordination model to evaluate the resilience of six cities along the Sichuan–Tibet Railway in China. Some studies have attempted to introduce more ideas for urban resilience assessment, including image analysis using radar images [
21], comprehensive models based on geographic information systems and AHP [
22], and hybrid methods combining network analysis and decision-making experiments [
23].
Based on the above discussion, it can be found that scholars have begun to pay attention to the resilience of large cities. However, the existing research on establishing an evaluation index system lacks the combination of urban resilience characteristics and rarely pays attention to the balance of internal subsystems of resilience while evaluating resilience levels. Meanwhile, the emphasis is only on the balance of subsystems while neglecting efficiency. In that case, it will significantly affect the construction of urban resilience [
24]. The driving force–pressure–state–impact–response (DPSIR) model has been widely used in evaluating complex systems due to its comprehensiveness, holism, and flexibility. It can fully characterize the relationships between various elements through causal chains and effectively evaluate the proper level of the target object. This model is based on complete logical relationships that could evaluate system changes’ causes, processes, and consequences [
25]. Structural checks can also be provided during the evaluation process, and feedback can be provided promptly [
26]. In addition, the data envelopment analysis (DEA) model can meet the efficiency evaluation with multiple input–output units without the need to determine indicators’ weights, and the evaluation results are objective and accurate. Hence, they are especially suitable for the evaluation research of complex systems such as cities [
27]. Therefore, this study attempts to analyze the resilience process and explore the characteristics of urban resilience based on the balanced perspective of internal subsystems, aiming to construct an urban resilience assessment model with an integrated perspective and comprehensive elements. This research will select evaluation indicators based on the DPSIR model that fit the characteristics of the resilience stage, Define the input–output properties of resilience elements in combination with the DEA model, leverage the advantages of the DEA model that does not require determining indicator’s weights and can handle multiple input–output elements, ultimately establish an objective and effective urban resilience evaluation indicator system. Selecting 105 large cities in China for a case study, the research object covers cities from all directions, types, and grades in China, analyzing the distribution and dynamic evolution of their resilience from 2017 to 2021. Finally, further study of dynamic evolution and difference analysis using the Malmquist index, Dagum Gini coefficient, and Markov chain propose reasonable suggestions based on the shortcomings of current resilience construction, which can obtain more universal resilience development laws.
The contributions of this paper are as follows: (1) under the guidance of urban resilience theory, based on the DPSIR model, indicators were selected from the five dimensions of “driving force–pressure–state–impact–response” to construct an urban resilience evaluation index system that reflects the process of resilience; (2) based on the resilience evaluation index system, DEA model was used to measure the resilience level and establish an efficient and accurate urban resilience assessment model; and (3) this study analyzes the dynamic evolution and spatiotemporal characteristics of urban resilience using the Malmquist index, Dagum Gini coefficient, and Markov chain.
4. Discussion
The evaluation results demonstrate that 105 large cities have achieved good results in resilience construction, with most cities achieving DEA effectiveness and maintaining a specific growth rate. However, resilience’s slow improvement still needs to be taken seriously. Although resilience goals have been frequently mentioned in the planning of various cities, there is still a lack of specific measures for urban transformation, ecological environment protection, and industrial structure upgrading [
7]. Therefore, it is recommended that the government and stakeholders participate in the construction together and carry out the resilience improvement in a planned manner. In addition, the government must fully recognize the balance between the driving force, pressure, state, impact, and response subsystems [
24], strengthen restrictions on pressure, focus on ecological improvement and social security, analyze the demand for resilience, and improve resource investment structures.
Based on the results of the Super-SBM model, the top ten cities with the highest and lowest average resilience were identified, as shown in
Figure 12. The top ten cities with the highest resilience mainly belong to coastal provinces, including cities of various sizes, such as Kunshan and Shenzhen. Although their strengths differ significantly, the eastern coastal regions are conducive to their socio-economy and resilience development. Beijing’s high resilience has been confirmed by other studies [
59]. Urumqi is vast and sparsely populated, and its urban development is influenced by the Western Development Strategy, which benefits its resilience construction [
60]. While among the ten cities with the lowest resilience, specific differences exist in their sizes and types. For example, Nanjing and Lanzhou are provincial capital cities in the eastern and western regions. Although there is a significant difference in their urban size, their resilience is similarly low. Central cities such as Nanjing and Qingdao have a high degree of social modernization. However, their urban development and resilience construction may be somewhat disconnected, and population pressure hinders the improvement of urban resilience. Small and medium-sized cities such as Zibo and Yichang may face many problems, such as an aging population, lagging economic structure, and ecological environment damage, which limit their resilience.
The combined effect of technological efficiency improvement and technological progress results in resilience gradually improving, but the process is slow. From the perspective of the decomposition index, there is not much difference in the contribution between technological progress and technological efficiency improvement, so more attention should be paid to improving management planning. To maximize the potential of existing technologies and improve resource utilization, each city could start by improving its management, updating technology, etc. Secondly, in the face of natural disasters, cities urgently need scientific disaster prevention and reduction plans. Community leaders should strive to popularize emergency self-rescue methods to the public and cultivate residents’ awareness of emergency safety. In addition, emergency infrastructure should be improved, and emergency material supply channels that can respond quickly should be established.
The current narrowing of differences in resilience is a positive signal that the distribution is gradually becoming more balanced. However, the internal differences among subregions still deserve attention, with the eastern subregion having the greatest. As the most developed region in China, there are significant differences in each eastern city. The central city has a large concentration of transportation, education, and medical resources, with a higher social modernization and advantages in resilience construction. Surrounding cities are easily affected by siphons, and issues such as population outflow and environmental pollution are all worth paying attention to. Therefore, from the perspective of urban planners, it is necessary to properly clarify the positioning of cities, strengthen interconnections, and do an excellent job at the top-level design of urban layout within the region. The central city continues strengthening scientific innovation, optimizing the social security system, and increasing environmental protection efforts. Surrounding cities actively improve infrastructure, attract talents to settle in, and do a good job supporting the central city.
The results of the Markov chain show that the resilience of large Chinese cities will exhibit good stability in the future, with a small probability of a decrease but also a low probability of an improvement. Larger cities occupy more resources but bear more significant population pressure. Their infrastructure is overwhelmed due to the inability to match population demand. Smaller cities experience population loss, which could make the infrastructure inadequate and outdated. Therefore, it is necessary to strengthen infrastructure in the current stage of resilience construction. Firstly, cities should strengthen public transportation and improve the urban transportation environment [
61]. Convenient transportation is the fundamental guarantee for strengthening urban connections and enhancing commercial exchanges. Secondly, the infrastructure related to social security, including education, healthcare, and other areas related to people’s livelihoods, should be improved. Finally, the ecological sector remains a crucial focus of urban resilience. Measures such as improving greening, increasing urban wetland areas, strictly controlling pollution, and strengthening atmospheric governance should continue to be taken.
Based on the previous analysis and discussion, it is fully demonstrated that the evaluation model of this study is feasible. This study accurately obtained the resilience distribution pattern of 105 large Chinese cities. At the same time, the resilience mechanism is deeply explored, the process of enhancing resilience is analyzed, and targeted suggestions are proposed based on the results, which other methods do not possess.
5. Conclusions
Accurately assessing resilience and its evolution is significant for enhancing the stability of current large cities. This study proposed a novel urban resilience assessment model, established an evaluation indicator system based on the DPSIR-DEA model, and conducted a case study on 105 large Chinese cities. The results indicate that this assessment model is objective and practical. The DPSIR model can accurately depict complex behaviors of urban resilience and construct complete logical relationships for it. The DEA model is equally compatible with urban resilience evaluation. It provides an accurate and efficient way to measure urban resilience.
This study measured the resilience of 105 large Chinese cities from 2017 to 2021. It analyzed their dynamic evolution characteristics and regional differences. Three conclusions can be drawn. Firstly, their overall resilience is relatively high, with a healthy olive-shaped distribution structure, but there is a significant polarization phenomenon. Secondly, from the perspective of dynamic evolution, comprehensive resilience has experienced a development trend that first increased and then decreased during the research period. The overall efficiency improvement depends on the combined effect of technological efficiency improvement and technological progress. In future predictions, the resilience will have good stability, and there is a certain probability that it will continue to improve. Finally, the regional difference of 105 large cities’ resilience is gradually narrowing. Currently, the internal difference in the eastern subregion is the largest, while the difference between the central and western subregions is the smallest.
Due to factors including perspective selection and data limitations, only relatively important and representative indicators were selected, and the research period was only set from 2017 to 2021. The latest evaluation results could not be obtained temporarily; therefore, the results may not be comprehensive. This is a limitation of this study, and it will be the focus of the author’s further research. In the future, when establishing an evaluation index system, the author will comprehensively consider the characteristics and elements of urban resilience and thoroughly consider urban behavior under the influence of risks. Future research will further expand the sample range, time, and city matrix to establish a more comprehensive and complete urban resilience assessment model. Our research team will conduct a comparative analysis with cities from other countries or regions by collecting more research data.