In this discussion section, we present and review the literature on urban renewal and sustainable development. First, we identify and review studies based on the most frequently cited articles and major areas of research. Then, we highlight the evaluation of sustainable urban renewal to identify innovations.
4.1. Review of Studies Based on the Most Frequently Cited Articles and Key Research Areas
The variation in annual citations can be used to assess the academic influence of publications [
32].
Figure 10 and
Table 5 show the total number of citations and the total binding force of the most productive authors from 2000 to 2020.
The total number of citations of articles published in the past six years is less than that published in 2013, 2011, and 2007, which experienced more citations due to the rapid development of sustainable urban planning research. Therefore, by comparing the total quotes of a publication,
Figure 10 shows that the analysis of the annual citations of a publication can provide more rational explanations and more precise details.
Table 6 and
Figure 12 present the seven main characteristics of the most frequently cited articles (more than 400 citations). They are notably different from the “ordinary” papers cited. Naturally, they are written by a large number of scientists, often involving international collaboration [
32,
48]. Based on the analysis of the annual citations of articles and their research axis concerning urban renewal and the practice of sustainable urban renewal, we selected seven highly cited papers in
Table 6, following a model of the largest number of citations to the smallest number. Our debate revolves around the results (quality dynamics and visibility dynamics) of these articles by introducing a vision of sustainability in urban renewal projects.
Of these articles, that written by Anna Chiesura in 2004, published in
Landscape and Urbanism and entitled “The Role of Urban Parks for the Sustainable City” [
36], is the most cited publication in sustainable urban renewal research during the study period of 2000–2020, with about 1043 citations. This document’s main contribution is to address the importance of the urban nature for citizens’ well-being and the sustainability of the cities they inhabit. Urban sustainability and regeneration strategies focus primarily on the urban environment’s artificial and constructed components [
31,
32,
52]. Urban collective gardens are seen as alternatives to address the environmental problems generated by urbanization [
53], thus contributing to cities’ sustainability [
48,
49,
50].
The interaction between urban renewal and public spaces has been highlighted in many studies. For example, [
48] analyzed the actors who shape urban green space development in a medium-sized city whose land shortages [
54], budgetary constraints, and community expectations are the source of the need for leadership [
55]. Regarding mobility, parks and green spaces are reconceptualized and advanced to solve multiple urban problems (such as social integration, storm-water mitigation, and health promotion) [
55].
To do this, providing urban green spaces consists of more than giving land and income for the development of facilities. Another study examined user-generated data to provide dynamic information regarding the use of urban green spaces [
53,
56]. and to understand and compare the capacity of the different data sets generated. Social media and surveys are therefore a rich and versatile source of data on activities and leisure. Such a reflection of the renovation of urban green spaces must be based on information about where, when, and how people use and value urban green spaces [
57,
58,
59] to make the project more sustainable. The fragmentation of urban green spaces using landscape measurements (case study: District 2, City of Tehran) [
60,
61,
62] and the potential accessibility of green spaces through data on urban artificial buildings in Nanjing was also assessed [
63,
64,
65]. According to the research by X. Du, X. Zhang, H. Wang, X. Zhi, and J. Huang [
17], we note that green spaces play an essential role in improving the health and quality of life of urban dwellers, which has become one of the most debated topics for researchers around the world, and the Chinese government in particular. The importance of urban parks in old urban centers has been particularly highlighted, and relevant measures have been recommended for residents’ well-being and the sustainability of the cities they inhabit.
In summary, governments should consider increasing green space supply and promoting equal access concerning the well-being of residents. According to the research by S. Nasehi and A. Imanpour Namin [
61], to understand the negative effects of inappropriate land use and land-use change, it is necessary to know and understand the process of exchangeability to assess sustainable urban development’s environmental impacts. This focuses on the use of land for urban parks in sustainable urban renewal projects through appropriate and sustainable use of natural resources.
The second most cited article is “Urbanization in developing countries: Current trends, future projections, and key challenges for sustainability” [
38], written by Barney Cohen in 2006 and published in
Technology in Society, with approximately 729 citations. This paper’s main contribution is to provide a general overview of recent urban growth trends in developing countries. It noted that the current levels and trends of urbanization closely mirror global industrialization and economic development patterns [
38]. By 2025, African society will become predominantly urban [
62]. As a result, Africa’s urban population is expected to more than double, from 295 million in 2000 to 748 million by 2030, so that within 25 years, Africa’s urban population will be larger than that of the continents of North America, Europe, or Latin America [
63]. The article also noted that much of the current debate on sustainable cities focuses on the challenging problems for the world’s largest urban centers. As a result, issues of urban sprawl and population expansion are considered necessary by various stakeholders.
Thus, the challenges of achieving sustainable urban development are particularly acute in Africa [
64]. A comprehensive understanding of future global urbanization trends could benefit from a long-term analysis of city size, which is a key variable influencing population growth [
60,
65]. Therefore, the analysis of changes in the relationship between a city’s size and population growth contributes to the debate on the future development of urban centers globally [
65].
In Africa, taking the example of the peri-urban area of the city of Bahir-dar in Ethiopia, based on a socio-spatial analysis of land use dynamics and the land response process, a previous study examined practical measures to combat and control undesirable changes in land use [
60]. Thus, a framework for monitoring land use interventions is needed for strategy implementation and decision-making in regulating and managing land-use dynamics in peri-urban areas. It is important to limit population expansion and peri-urban sprawl using an integrated approach to solving existing problems while considering the capacity of financial resources. This is because urban dwellers continue to reside in much smaller urban areas, and rapid urban growth in cities in developing countries severely exceeds most cities’ ability to provide adequate services to their citizens. Therefore, the challenges in achieving sustainable urban development are mainly located in Africa [
64]. The Millennium Development Goals (MDG) are a plan endorsed by all countries globally and by all major global development institutions to eradicate hunger and poverty. Unfortunately, many African cities continue to experience uncontrolled growth of the population, unrestrained spatial growth, hunger, and precarious and worsening living conditions. In contrast, large reserves or former industrial reserves exist in the center of well-developed cities with dilapidated and unsanitary conditions, whose renovations make them challenges for sustainable development.
In other continents, urbanization is interpreted as a manifestation of agglomeration economies and, following this logic, a concentration of urbanization around a single site could result from particularly effective agglomeration economies [
66]. In the Amazon, the previous study underlined the importance of researching urban planning, and enhancing the context and the daily existence of the lifestyles specific to each place. Hence, in the case of the Amazon, the need to link urban theory to an “empirical course,” as suggested by J. A. Telles in 2006 [
67], introduces the notions of context and practice to the heart of the debate in social sciences, and is a trajectory that has been insufficiently analyzed to date. This practice could lead to strong urban growth around a single site, thus causing various problems, such as the shortage of drinking water, sanitary issues, and congestion. Therefore, it may be preferable to confront these problems directly rather than attempt to articulate a mode of intervention around a development issue.
The third most cited article is “Supilinn, Tartu—The lively vernacular against urban renewal: A Lefebvrean critique” [
43], written by Nele Nutt, Mart Hiob and Zenia Kotval in 2016 and published in the journal
Space and Culture, with about 646 citations. This paper studied many aspects of urban development (urban analysis, human values, adopted space projects, etc.) to provide an overview of the issue that characterizes the city as being animated by reliable planning and design. However, current efforts to regenerate the region can ruin the precious vernacular environment [
68]. Nonetheless, officials respond to real demands by creating new spaces and transforming unpleasant spaces.
The importance of integrating culture into a built heritage for a sustainable city [
69] is a reason to abandon the idea of demolition in favor of improving living conditions in old urban centers. For example, community left to die has been resurrected using bottom-up planning and citizen initiatives to become one of the preferred places to live, to the point that the neighborhood today faces the threat of gentrification with social displacement and complete renewal [
69]. According to the research by M. Ročak, G. J. Hospers, and N. Reverda [
68], social capital can facilitate social sustainability in the context of urban shrinkage [
68,
70]. However, trust and empowerment are not guaranteed in the context of this shrinkage. More investments should be made in cities in decline to foster cooperation between civil society and politics, resulting in the development of mutual trust [
66,
68]. However, a slum that survived the socialist government system has turned into a sustainable residential area through an urban renewal process. In addition, the best qualities of its outlook outside the site are well-preserved buildings, plot structure, authentic historical surroundings, natural surroundings, and a healthy community.
In summary, social sustainability is often combined with social conditions such as a sense of belonging, trust, participation and resources, empowerment, cultural identity, and quality of life [
22]. Thus, sustainable urban renewal must involve particular “aesthetic qualities,” with buildings that they qualify as “of a certain standard” or in a “beautiful and harmonious architectural space that retains its cultural identities” [
71]. To avoid saying “if they are razed, there is nothing left,” urban renewal is forced to integrate “quality,” “harmony,” and “cultures” to achieve urban sustainability [
72].
The fourth most cited publication is entitled “The Changing Metabolism of Cities” [
46], written by Christopher Kennedy, John Cuddihy, and Joshua Engel Yan and published in the
Journal of Industrial Ecology in 2007, with 630 citations. The main contribution of this paper is an overview of the evolution of the metabolism of cities. This paper also identified metabolic processes that threaten the sustainability of cities. These include altering groundwater levels, depleting local materials, accumulating toxic materials, summer heat islands, and irregular accumulation of nutrients [
69]. According to the research by M. Hiob and G. Lyons [
73,
74], the urban metabolism, which concerns the flows of material resources and waste that characterize the functioning and sustainability of a city, are fundamentally associated with human behavior.
Although humans have existed for a long period, emissions generated through human activity have become so pervasive and that they appear to rival natural processes. To address this issue, we must quantify problems caused by urban metabolism or related to the exploitation of environmental resources, and mitigate them to achieve sustainable urban development. Many researchers consider urban metabolism to be a concern common to all humanity. Thus, a panoramic analysis of the research progress of the urban metabolism was carried out based on trends and the current situation [
62,
63]. This paper proposed future research directions in climate change and targeted policy directions for diagnosing sustainable urban problems. According to the research by T. Dai and R. Liu [
75], the issue of resources and the environment in Beijing, the center of China’s politics, economy, and culture, has become a focus of attention, both domestically and internationally. This analysis, which was based on the Tapio decoupling model and the logarithmic division index method, was used to analyze the level and influence of Beijing’s dematerialization factors [
75]. The results of the study showed that, from 1992 to 2015, Beijing’s GDP increased from 61.25 billion yuan to 623.45 billion yuan; during the same period, direct material inputs and domestic production were also transformed, increasing from 139.88 and 78.63 million tonnes in 1992, to 205.17 and 166.27 million tonnes, respectively, in 2015 [
75]. This study concludes that the influencing factors of dematerialization can be quantified to provide a scientific basis for the future sustainable development of the city. According to a mission report by ANRU (the national agency for urban renovation) [
76], 396 projects approved by the ANRU committee involved the regeneration of 332,481 units of social housing, the upgrade of residential areas for 338,853 units, the demolition of 139,986 units, and the restoration of 135,979 units, and provided funding for home improvements and equipment [
76]. For the mission of monitoring the demolition of several high-rise buildings, expertise was applied to the reuse of demolished materials for the development of public spaces and construction of new living environments. Several prototypes have been constructed from reused materials to create continuity between the past and the future of this district. The main objective is to forge a social bond between residents and local structures (schools, neighborhood associations, neighborhood authority) within this new place of life.
In summary, urban metabolism examines the type and quantity of resources that fuel the city and its people, to highlight prospects for sustainability [
77], and allow more holistic intervention strategies for integrated and sustainable urban renewal. Thus, urban metabolism is more than an urban development project. Above all it is a political project, in which local authorities attempt, with the assistance of external providers, to make the city of tomorrow more sustainable.
The fifth most cited article is “Entitled Rethinking Sustainable Cities: Multilevel Governance and ‘urban’ politics of climate change” [
49], written by Harriet Bulkeley and Michele Betsill in 2005 and published in
Environmental Politics, with approximately 569 citations. This article highlights a multilevel governance perspective to examine the discursive and material struggles which take place in creating sustainable cities [
49]. Investments in urban equipment (infrastructure) contribute to a country’s economic development by facilitating its opportunities. However, the analysis of urban governance objectives in sustainable cities has also led to a relatively impoverished view of the governance context in many sustainability reports. As climate change is one of the most common problems of our time, a critical analysis of the role of cities in tackling climate change and the prospects for urban sustainability is of interest to researchers interested in local and global sustainability. Local adherence to best practices highlights the authentic struggles of urban sustainability locations in competition with other governments seeking to shape the sustainable urban future [
74].
Accordingly, research into sustainable development in urban renewal includes the search for new tools and renewed legitimacy [
75,
78], which focuses on the assessment of sustainability as a key technique and method to pursue the political objective of “sustainable development” in urban planning.
Based on the model of the most cited articles in our analysis, the sixth most cited article is entitled “A SWOT analysis of the field of virtual reality rehabilitation and therapy” [
50], written by lbert Rizzo and Gerard Jounghyun Kim in 2005 and published in
Teleoperators and Virtual Environments, with about 484 citations. This strengths, weaknesses, opportunities, and threats (SWOT) analysis suggests that the field of virtual reality rehabilitation is still at an early stage of development, characterized by successful “proof of concept” systems, encouraging initial research results, and a few applications finding their way into common and practical clinical use. Many virtual reality strengths are specified and continue to justify the evolution of existing applications and new creations. For example, this virtual reality force analysis can be used in urban renewal and sustainable urban development as a general examination of strength, threats, opportunities, and weaknesses to make proposals for the sustainable reconstruction of old urban neighborhoods. An analysis based on SWOT [
79], of experienced rapid advancement and technology, which has established itself as a valuable training tool in many fields, was carried out to promote off-site construction in the context of China’s new urbanization.
This document also offers roadmaps and top-to-bottom implementation strategies that could significantly contextualize China’s New National Urbanization Plan 2014–2020 and help the Chinese construction industry improve its urban land renewal skills. Introducing SWOT in urban renewal is recognized as a guideline towards sustainable development. A study based on SWOT facilitates a deeper understanding of the development status of planning management of prefabrication housing production (MPHP) in Hong Kong. The balance between supply and demand for housing is one of the most critical concerns in Hong Kong, which is why SWOT analysis offers the opportunity for major players to perceive the external and internal conditions of the development of prefabrication in Hong Kong [
49,
80].
In summary, SWOT-based analysis has seen rapid advancements in force-based virtual reality technology, but remains a challenge in many areas. SWOT analysis can be used in urban renewal and sustainable urban development as a general examination of strength, threats, opportunities, and weaknesses to make proposals for the sustainable reconstruction of old urban districts.
The seventh most cited article is entitled “The compact city fallacy” written by Michael Neuman, and published in the
Journal of Planning Education and Research in 2005, with 409 citations. This article examined empirical evidence on the sustainability of compact cities whose urban sprawl has been debated to achieve the goals of these cities. However, the re-examination of old urban centers is a sustainable solution to limit urban sprawl and make cities compact. A design error of the compact city [
78,
81] has resulted in an increase in light and air. This has led to a less compact urban form, and the paradox is still unresolved despite recent research into compact cities, smart growth, and community health, and new urban planning efforts. The document concludes that designing the city in terms of form is neither necessary nor sufficient to achieve compact and sustainable city goals. Sustainability and mutability converge around the reconstruction of the city in the city [
82]. Instead, designing the city in terms of process is more promising in achieving a sustainable city’s elusive goal [
78,
83]. For example, the project in Besancon [
50], aims to assess the consequences of implementing a future urban renewal scenario at the urban level by 2030 based on the use of old fortifications.
In summary, linked to urban renewal and the compact city, a large amount of work has been evaluated and carried out for more sustainable urbanization. This is based on the interest in these spaces in terms of urbanization (urban form and mobility) and on a simulation of the urban growth over a long-term horizon, as part of a compact urban renewal scenario.
4.3. Innovations
Cities typically face various challenges, such as urban degradation, environmental deterioration, lack of infrastructure, social problems, and economic decline [
91]. Urban renewal is considered the ideal concept for the development of sustainable cities through various actions. This allows urban development to be considered as a system. According to Peter Drucker, “the best way to predict the future is to create it.” Thus, based on literature reviews since 2000, we chose the keywords related to urban renewal and sustainable urban development. These were then analyzed using VOSviewer to identify the hot spots for future research. For each of the 10,576 keywords found by a pooled analysis of search results, the total strength of co-occurrence links with other keywords was calculated in VOSviewer. Of the 3971 publications analyzed, 1623 publications contained the keyword “urban renewal”, for which the total link number was 28,717. The keyword numbers for each publication were estimated to be between 4 and 5. We note that some keywords have similarities, namely, “urban renewal” and “urban development,” “urban regeneration” and “urbanism,” and “urban area” and “sustainable city”; these similar keywords helped us to study our case further. To better assess and identify hot spots for future research, we selected 1000 individual keywords with strong links for further analysis, as shown in
Figure 13. By synthesizing common words and cluster analysis of database samples, the subtitles illustrate the keyword network of publications frequently linked to sustainable urban renewal from 2000 to 2020 (
Figure 13). The popular research topics of urban renewal are defined by a complex system [
69] based on cities’ key impacts and issues.
The grouped analysis of research results of the most cited articles by quotation topic from each country is an essential indicator of urban renewal and sustainable urban development research. This analysis indicates the scientific influence of a country in the current research. Among the 15 most productive countries, the United States was 18.20% and the United Kingdom was 13.66%. However, each country’s quotes also depend on the productivity of institutions, and the above data shows that the United States and the United Kingdom have more citations than other countries (
Table 6). The results show advanced progress in research on urban renewal. This clearly demonstrates that sustainable urban renewal is essential to the sustainable development (SD) strategy, because cities are responsible for most of the world’s environmental carbon and resource footprints, and are home to more than half of the world’s population [
64].
Consequently, the potential for synergies between urban renewal and the objectives of sustainable development goals enabled us to orient, in summary, four main areas of future research to improve the performance of methods and policies, and identify relevant factors for sustainable urban renewal. Primarily, critical analysis of the internal and external origins of urban and societal problems was undertaken. Then, we focused on the impacts and challenges of urban renewal to develop land and improve the population’s living conditions and environmental quality. Our strategies also offer a unique opportunity to mobilize all stakeholders regarding the new urban renewal dimensions in a vision of urban sustainability. However, the different parties must engage in the decision-making for innovative solutions to make the urban renewal project sustainable. Urban renewal is a subject of increasing interest in a range of research related to improving and maintaining the living conditions of habitats and the quality of the environment, for a vision of sustainability.
Figure 14 shows the axes of future research: (1) evaluation (strengths, weaknesses, opportunities, and threats); (2) analysis of internal and external origins; (3) engagement of different stakeholders; and (4) innovative solutions. In developing our four axes of future research on sustainable urban renewal, evaluation and analysis were combined to facilitate understanding. We also proposed major directions that will be the subject of future research.
4.3.1. Evaluation and Analysis
The evaluation conducted in this study provides insights into the development of sustainable urban renewal. Based on the previous information, the evaluation is a reflection of awakening and mobilizing local actors to adopt the concept of sustainable communities. Evaluation can help strengthen actors’ collective capacity to act on a given policy, which is a key issue in urban renewal projects whose success depends on the mobilization of many actors and the fragmentation of resources between several institutions.
Evaluating residential mobility in sustainable urban renewal means explaining that land is an essential element and the basis of any urban renewal project. Sustainable urban renewal is also a re-examination of industrial wasteland in cities where the scarcity of land has become one of the main environmental, ecological, and health issues for local communities. However, “nothing is lost, nothing is created, everything is transformed”, as Antoine-Laurent de Lavoisier said [
92]. If several factors are responsible for the birth of brownfields, these spaces are often located at the city’s heart. These spaces house key infrastructure services and are close to utilities and facilities. These abandoned wastelands allow real economic, social, and environmental opportunities and optimize abandoned industrial land remediation. This study examined various methods that have been previously developed for urban renewal or urban revitalization of different cities towards a vision of sustainable development. However, the results cannot be compared and may not be consistent with those from other assessment methods.
Another problem is the lack of data required to create social dynamics in neighborhoods, define the groups of inhabitants eligible for housing, and compensate for displacement related to urban renewal operations. A sustainable, fertile, resilient, and intelligent city relies on responsible governance of communicative and environmentally friendly resources and infrastructure, and seeks a high quality of life (urban comfort, convenience, transport, housing, and access to health, education, and culture), in addition to a good work and rich social life. A sustainable solution requires urban renewal, the establishment of an appropriate urban policy, or the rehabilitation of brownfields to reduce urban sprawl and land consumption. In short, the re-use of brownfields also contributes to sustainable urban development, which can be achieved by local authorities by establishing an excellent political and regulatory system. Monitoring of excellent multi-actor interactions is a condition for sustainable urban governance and sustainable urban renewal. Most of the existing research focuses on the social, economic, and environmental assessment of urban renewal. We invite researchers in future urban renewal evaluations to focus on in-depth assessments with four dimensions: social, cultural, economic, and environmental.
4.3.2. The Various Stakeholders
An urban renewal operation aims to transform the social housing neighborhoods that face many problems: being enclosed, remoteness from the rest of the city, economic and social difficulties, degraded outdoor spaces, a lack of public services, etc. Urban renewal is becoming a lasting success through the participation of all stakeholders in the project. This can take many forms: simple identification, information, consultation, mediation, negotiation, collaboration, partnership, and delegation of power. Among these stakeholders, public authorities play a key role in promoting sustainable urban renewal through efficient policies, regulations, and programs. This facilitates the participation of residents in decisions, not only as users, but also as full players in urban renewal projects that are beginning to take hold. To achieve sustainable urban renewal, the various stakeholders must analyze and resolve internal problems (strengths and weaknesses) and external origins (threats and opportunities). Another area of research in the context of sustainable urban renewal is the proposal to public authorities and private partners to act together on existing fabrics by promoting the intensification of residential neighborhoods, the transformation of activity areas, and the rehabilitation of buildings under a genuinely sustainable vision. In summary, the engagement of all stakeholders in the decision-making process in terms of effective collaboration, including the involvement of resident, is essential for future research on sustainable urban renewal. We also invite future research to be articulated around the development of cooperation between cities to exchange experience based on the research into tools and urban renewal methods; the search for new financing techniques for urban renovation projects; and finally, the preservation and reuse of built and industrial heritage by respecting the conservation of the urban renovation project’s environment.
4.3.3. Innovative Solutions
In reality, the problem of a city relates to the precariousness of the lives of its inhabitants, and the fact that the city itself cannot improve inhabitants’ living conditions. Thus, after the analysis of the internal and external origins of urban problems, all stakeholders must decide unanimously to work toward a vision of sustainability as a solution to the various urban problems. In this sense, urban renewal is an effective solution for sustainable urban development over time and in well-managed spaces. Urban renewal and sustainable urban development are recognized as important tools to facilitate the reflection and visualization of the future [
70]. An urban renovation project is sustainable, first, when an excellent multi-actor interaction is a prerequisite to sustainable urban governance and sustainable urban renewal; and, second, when the definitions of urban policies and rules are clear.
In general, priorities are proposed to consider the inhabitants’ concerns and the central players in urban planning, for which the consultation method is varied. The main focus is to facilitate cooperation between the various stakeholders to renovate cities or neighborhoods sustainably. Therefore, it is necessary that all stakeholders are committed to finding innovative solutions. This also offers possibilities for future studies that refer to 1) the scarcity of urban land in developed countries (assessment of the renovation of abandoned areas or brownfields, depending on soil pollution); and 2) urban sprawl and demographic growth in developing countries (the renovation of old urban centers to limit population and spatial expansion as a sustainable solution).