Urban in Question: Recovering the Concept of Urban in Urban Resilience

Abstract

Existential threats from climate change, weather-related disasters, and other crises have drawn increasing attention to urban resilience. Prior work has focused on explicating resilience and proposing various definitions of it. But the emphasis on describing resilience might overlook what urban means in discussions of urban resilience. This paper investigates how urban resilience scholarship conceptualizes and defines the term urban. I conduct a literature review and content analysis of recently published urban resilience articles. The results reveal how urban is prominently featured, but its conceptual use is not identified, and the term is left undefined. The findings suggest serious concerns about the applicability and generalizability of urban resilience to different contexts. The paper contributes to the literature by showing how conceptualizing urban alternately as a shared subject of study, influential condition, or measurement category has far-reaching implications for urban resilience planning, implementation, and assessment. Drawing upon the idea of simulated annealing, the paper suggests that taking a few conceptual steps backward may help our understanding of urban resilience—and cities to bounce back better.

1. Introduction

Growing concerns about the effects of climate change, the frequency and severity of weather-related disasters like hurricanes, floods, and wildfires, the COVID-19 pandemic, and other crises, have brought increased interest in the idea of urban resilience. Urban resilience has attracted scholarly attention that spans across many fields, including ecology, emergency management, engineering, planning, geography, and urban studies [1,2,3,4,5,6,7,8,9]. Institutions, such as government agencies, non-governmental organizations, and philanthropic foundations, promote urban resilience as a quality to be developed, a governance model, or a goal to be achieved [10,11,12,13,14,15].

However, there remain questions about what urban resilience means and how it will help cities be sustainable and bounce back better from shocks. Prior academic work has sought to elucidate the idea of resilience and proposed different definitions of it [2,3,4,9,16,17,18,19,20]. As debates continue, the emphasis on explaining resilience raises questions about what urban means in the context of urban resilience. A clear conception of the term urban is important not only because it comprises half of urban resilience but also because it influences scholarly discussions and the application of urban resilience in practice.

This paper investigates how the urban resilience literature conceptualizes, defines, and explains the term urban for urban resilience. I conduct a comprehensive literature review and content analysis of peer-reviewed urban resilience scholarship that was recently published in academic journals. The results reveal how the term urban is left undefined and its conceptual use is not identified despite being prominently featured and repeatedly invoked. The findings suggest potential problems with the applicability and generalizability of urban resilience to different geographic, political, social, and cultural contexts. Furthermore, many of the same concerns, criticisms, and unanswered questions that have centered on the meaning of resilience may also apply to the meaning of urban. Understanding urban alternately as a shared subject of study, influential environmental condition, or analytic measurement category has important implications for urban resilience planning, implementation, and assessment. The discussion draws upon complexity theory and the idea of simulated annealing to suggest that taking a few conceptual steps backward may help our understanding of urban resilience—and cities to bounce back better in the face of threats. The paper contributes to the literature by revealing how urban resilience scholarship under-conceptualizes what urban means and by showing how different urban concepts can be applied to urban resilience.

The rest of this paper proceeds as follows. The next section highlights different concepts of the term urban that have emerged from scholarship across several fields. The following section describes the method for selecting urban resilience articles to review. Then, I present the findings and discuss the implications.

2. Literature: Urban Concepts

The term urban is often used to describe some aspects related to cities. But beyond this broad, general observation, there is little shared agreement because there are many different aspects to consider. Previous work has used and understood the term urban in different ways, which can be loosely organized into three types: urban as describing a shared subject of study, urban as a condition that is experienced and that affects aspects of life, and urban as a specific measurement category.

2.1. Urban as a Subject of Study

Substantial academic attention has been devoted to identifying and claiming the intellectual territory that is encompassed by the term urban as a coherent subject of study. Much of this work can be found in debates among scholars of urban theory and urban studies. A simplified version of the arguments is presented here.

A conventional view holds that urban refers to a typical or commonly accepted notion of cities, which draws heavily upon principles in standard economic theory. In this view, urban refers to a densely occupied place of economic activity that is reflected in land uses, which aligns with the basic economic description of cities. The shared features of cities and the reasons why they exist are topics covered in a large economics literature [21,22,23]. A recent exposition argues that cities can be understood in a theoretical framework that incorporates two elements: (1) agglomeration and (2) the urban land use nexus [24]. Agglomeration in the context of agglomeration economies refers to the benefits that arise when individuals and firms locate near each other. The reasons for agglomeration include transportation costs, labor matching, and knowledge spillovers [25,26,27]. The urban land nexus describes a collection of land uses that reflect concentrated social and economic activities among people that play out in space. These land uses result from the occurrence of agglomeration, as firms and individuals seek places to locate in relation to each other and in response to land prices and other factors.

Some scholars criticize the underlying basis of the urban concept outlined in the conventional view, which raises questions about generalizability. The conventional view rests on biased foundations because it was developed by drawing exclusively upon a small set of examples located in Europe and North America and selectively reflects Western ideologies [28,29,30]. Prior work privileges Western cities while taking a developmentalist perspective that perceives cities in poor countries as inferior and not advanced [31]. But there are many cities beyond the so-called global cities that have attracted scholarly attention and are held up as models of modernity and development [28]. This critique implies that findings from a small set of cities in a small number of locations may be flawed and may not apply to cities in different parts of the world that have otherwise been overlooked or excluded from study.

An alternative view suggests that urban processes should be understood across a broader context, even on a global scale, as opposed to individual cities. It builds on the idea of a ‘complete urbanisation of society’ that renders urban boundaries meaningless [32]. One expansive view takes the position that transformations in recent decades can be described as the urbanization of the world [33] or planetary urbanization, where the “urban represents an increasingly worldwide, if unevenly woven, fabric in which the sociocultural and political-economic relations of capitalism are enmeshed. This situation of planetary urbanization means that even sociospatial arrangements and infrastructural networks that lie well beyond traditional city cores, metropolitan regions, urban peripheries and peri-urban zones have become integral parts of a worldwide urban condition” [34] (p. 751). This view holds that urban processes are connected to large swaths of territory beyond traditional city centers and have global effects that cannot be escaped.

Finally, there is a notable counterview that questions—and even dismisses—the idea that the term urban can be used to distinguish a focus of study. Prominent work argues that the issues studied in urban sociology, such as social organization, are the same issues studied in sociology writ large [35]. Therefore, urban sociology does not meaningfully delineate a distinct subfield of sociology. This argument suggests that the use of urban in this context obscures more than it illuminates. Furthermore, ‘the urban’ may not even be a coherent object appropriate for scientific study [36].

2.2. Urban as a Condition

Other fields have developed an understanding of the term urban as a condition that people experience and one that affects various aspects of life. Early work in sociology posits that the urban environment can be seen as a construct that might influence social life, including social behaviors and relationships [37]. This concept builds on prior work that describes the heightened sensory stimuli and conflict experienced in cities, compared to other environments, and how people respond to those cues [38,39]. Although the urban condition is closely tied to cities, it can also be observed in other areas [37].

Some scholars criticize the use of urban to describe a unique condition and question its explanatory power. For example, there is little agreement about the characteristics that distinguish the urban condition from other conditions [40]. Many aspects of urban life do not depend on cities at all and are also visible in small, low-density areas that would not be considered urban [41]. A broader critique argues that the attention on urban as a condition is a distraction from larger concerns because it conceals the essential nature of cities as products of capitalism [42]. In other words, the formation and existence of cities ultimately reflects the forces of capitalism in operation as some actors take control of land and profit from it. Therefore, urbanization can be attributed to the capitalist mode of production and capital accumulation, which is the overarching issue to address [43,44].

The initial conceptualization of urban as a descriptive condition eventually shifted toward using the concept as a tool for analysis. If urban can be understood as a factor that explains differences and outcomes, it can be treated as an independent variable [45]. A large body of work uses this approach to study crime and social disorder, housing demand and affordability, immigration, poverty, and many other topics [46,47,48,49]. These studies are found in different academic disciplines and fields, but what they share is an outlook that the urban condition may be a contributing factor to observed outcomes.

2.3. Urban as a Measurement Category

Another way that the term urban is used is as a measurement category based on specified criteria. The category is employed to label a distinct physical and spatial entity. The category approach reflects the view that urban places emerge from a growth process and represent a point on the spectrum of forms of human habitation; see Figure 1. The urban category is typically assigned by a government agency or non-governmental organization to designate a specific place. The designation is often adopted for administrative, policymaking, and research purposes, for example to determine jurisdiction, to allocate and distribute resources, or to establish a unit of analysis. It typically includes defined spatial boundaries, which are often determined by some combination of political and geographic considerations but can also be influenced by economic, social, cultural, and environmental factors [50,51,52].

Many different criteria can be used to make a determination of a given place as urban. Common criteria include the number of inhabitants, population density, and level of economic activity [51,53]. Places that exceed a stated threshold for these criteria are assigned the urban label. Other criteria include building density, housing density, level of infrastructure (such as roads, streetlights, schools, or medical facilities), types of economic activity, proportion of geographic area covered by constructed materials or impervious surfaces, and combinations of these criteria [51].

However, there are well-established concerns with how urban is used as a measurement category. The choice of criteria to define urban is subjective, while the numerical thresholds assigned to the criteria are arbitrary [51]. In addition, the designations based on these criteria may be inaccurate or have low validity in terms of identifying the types of places that are intended [54]. Furthermore, each national government makes its own choices about which criteria to consider and what thresholds to establish for each criterion, so what is considered urban in one country might not be considered urban in another country [55]. Indeed, the statement that more than half of the world’s population lives in urban areas depends on different countries’ own definitions of urban, which are not consistent [51,55]. Various government agencies or non-governmental organizations within a country sometimes employ different criteria, which can lead to inconsistent designations. Agencies can also change the criteria or thresholds, so what is classified as urban in one time period might not be the same as another time period. As a result, there is substantial variation across and within countries in the types of places that are labeled urban. For example, the minimum population size required for an area to be considered urban covers a wide range, from 200 (Denmark, Iceland) to 50,000 (Japan) inhabitants [51]. According to the United Nations, “given the variety of situations in the countries of the world, it is not possible … to adopt uniform criteria to distinguish urban areas from rural areas” [56] (p. 106). Overall, there is no universally agreed upon description for determining the urban measurement category.

3. Materials and Methods

The scholarly literature on urban resilience was studied to examine how existing work conceptualizes the term urban for urban resilience. The focus is on published work that discusses the definition of urban resilience. The methodology consisted of data collection, data analysis and identification of gaps.

The Web of Science database was used to find published articles. This database was chosen in order to focus on English language articles that were peer-reviewed and that appeared in established academic outlets. Publications solely listed in other databases were excluded from the study. The time frame for the literature search was from 2016 to the present, because it is the period since a highly cited article [18] was published that noted concerns with the characterization of urban in prior literature. The time frame also reflects the heightened attention and focus of recent work on the definition of urban resilience.

The search was conducted by topic using the words “urban resilience” and a truncation of the word “define”. This search yielded 190 results. One duplicate record was removed. The remaining records were screened on title, keywords, and abstract. To focus on the most prominent and potentially influential work, articles were excluded if they were not cited at least one time. The full texts of the remaining articles were sought for retrieval. Nine articles were excluded because the full text was not available. After reviewing the full text of these results, 34 articles were excluded because they did not include a definition of urban resilience or of resilience. The excluded articles included the word ‘definition’ or similar words in the text without offering a definition or made only a passing reference to urban resilience; see Figure 2.

The remaining articles directly address the definition or meaning of urban resilience, for example by proposing a definition or discussing what the term means. These articles were examined to identify definitions of urban resilience proposed and to identify how the term urban was used and conceptualized. The results presented below highlight the most highly cited articles as examples, while the other articles included in the review are also referenced.

A few limitations should be noted. By focusing on articles, books were excluded from the search. The search also excluded working papers, conference proceedings, white papers, and other materials that were not published in academic journals or are not included in the citation database. The search was limited to articles that were published in English, so it does not reflect all work on this subject.

4. Results

Recent urban resilience articles that address the definition of urban resilience can be broadly organized into three groups: (1) reviews of prior literature, (2) frameworks or models, and (3) empirical studies. (For definitions of urban resilience presented in the most highly cited articles, see Appendix A 

Table A1. Proposed definitions of urban resilience in most highly cited articles published since 2016.

Authors and Year	Proposed Definition
[18]	“Urban resilience refers to the ability of an urban system—and all its constituent socio-ecological and socio-technical networks across temporal and spatial scales—to maintain or rapidly return to desired functions in the face of a disturbance, to adapt to change, and to quickly transform systems that limit current or future adaptive capacity” (p. 39).
[63]	Urban resilience is “the capacity of a city and its urban systems (social, economic, natural, human, technical, physical) to absorb the first damage, to reduce the impacts (changes, tensions, destruction or uncertainty) from a disturbance (shock, natural disaster, changing weather, disasters, crises or disruptive events), to adapt to change and to systems that limit current or future adaptive capacity” (p. 4).
[88]	Urban resilience is “[t]he capacity of an urban system to absorb disturbance, reorganize, maintain essentially the same functions and feedbacks over time and continue to develop along a particular trajectory. This capacity stems from the character, diversity, redundancies and interactions among and between the components involved in generating different functions. Resilience is fundamentally non-normative and an attribute of the system and applicable to different subsystems” (p. 269).
[93]	Urban resilience is “the passive process of monitoring, facilitating, maintaining and recovering a virtual cycle between ecosystem services and human wellbeing through concerted effort under external influencing factors” (p. 145).
[101]	Urban resilience is “the capacity of individuals, communities, institutions, businesses, and systems within a city to survive, adapt, and grow regardless of the kinds of chronic stress and acute shocks they experience” (p. 110).

).

4.1. Reviews of Prior Literature

Meerow et al. [18] review the abundant literature on urban resilience in order to identify common themes and issues. A motivation for the article is the growing popularity of resilience as well as the challenges of urbanization. Based on a review of 25 previously published papers that include a definition of urban resilience, the article argues that the concept has not been defined in a consistent manner. Through this review, the authors identify six issues essential to urban resilience: the definition of urban, system equilibrium, impressions of resilience, system change mechanisms, adaptation, and timescale. The authors propose a new definition of urban resilience that seeks to address the identified issues. The proposed definition refers to “an urban system-and all its constituent socio-ecological and socio-technical networks across temporal and spatial scales” [18] (p. 39). Urban or some form of the term appears nearly 150 times in the article.

It is important to highlight that one of the issues raised in the article is that urban is not clearly defined in past urban resilience papers. This is a rare acknowledgement of the problem. It is also one of the only articles to directly confront what urban means. To address this issue, the authors elaborate on the term urban systems: “‘Urban systems’ are conceptualized as complex, adaptive, emergent ecosystems composed of four subsystems—governance networks, networked material and energy flows, urban infrastructure and form, and socioeconomic dynamics—that themselves are multi-scalar, networked, and often strongly coupled” [18] (p. 45). A conceptual diagram is included to help visualize the urban system.

This article makes a noteworthy effort to address the question of what urban means, but there are several important issues to consider. The definition of urban resilience presented in the article specifically refers to an ‘urban system.’ This choice raises the question of what distinguishes an urban system from something that is simply urban. The article does not provide a description or explanation of the difference. The authors’ conceptualization of an urban system as a complex adaptive system, which includes some important characteristics that draw upon ideas from ecology and other fields, has been suggested by many previous scholars [57,58,59]. While this conceptualization is increasingly popular, the challenge remains in identifying what is distinctive about urban systems given that many things can be described as complex adaptive systems [60,61,62]. In addition, the definition notes that urban systems consist of subsystems, examples of which are listed but not explained. Furthermore, the listing of urban infrastructure and form as one of the subsystems of the urban system risks being circular as far as the meaning of urban is concerned. It also raises concerns about the standards of what is considered urban infrastructure and form and whether these standards exclusively draw from and are biased by Western, global North, developed world, or other perspectives. Finally, the definition does not appear to include any criteria like population size or density, which means systems that would otherwise not accord with prevailing notions of the term urban, like tiny systems, with a very small number of inhabitants, and sparsely settled systems, with a low concentration of inhabitants, may still be classified as urban systems according to this definition.

Ribeiro and Gonçalves [63] also use a literature review approach in seeking to identify the basic components and characteristics of urban resilience. The article is framed around the growth of cities, the development of cities, and the challenges for cities. Based on a review of the literature, it compiles nearly 30 definitions of urban resilience from agricultural and biological sciences, engineering, environmental science, social sciences, and other fields. The authors then proceed to identify common themes, which they describe as four pillars (resisting, recovering, adapting, and transforming), five dimensions (natural, economic, social, physical, and institutional), and eleven characteristics (redundancy, robustness, connectivity, independence, efficiency, resources, diversity, adaptation, innovation, inclusion, and integration) of urban resilience. According to the authors’ proposed definition, urban resilience involves the capacity of “a city and its urban systems” [63] (p. 4). Urban or some form of the term appears nearly 170 times in the article.

Despite collecting many different definitions of urban resilience, and offering their own definition, the concept of urban is left unexplained. The authors’ proposed definition of urban resilience refers to a city and its urban systems, but the rest of the article does not state what is meant by a city and what is meant by urban systems. The article also does not explain what the difference is between a city and its urban systems or if a city is simply the collection of its urban systems. The text of the article parenthetically lists six urban systems (social, economic, natural, human, technical, and physical). It is noteworthy that the article explicitly states humans are involved in urban systems, unlike other articles. However, the urban systems listed in the text are different from the ones shown in the article figures depicting cities and urban systems in the context of urban resilience. These urban systems overlap somewhat with the four urban subsystems stated in Meerow et al. [18], but the differences are not explained. Like many other articles, the authors’ proposed definition makes no mention of population size, population density, level of economic activity, or other criteria related to the concept of urban.

Other recent literature review articles on urban resilience [64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87] also refer to urban systems without offering an explanation, use urban and cities interchangeably, or otherwise do not describe what the term urban means.

4.2. Frameworks or Models

Elmqvist et al. [88] address the relationship between urban resilience and urban sustainability, including confusion about how the concepts are used. The authors assert that the contemporary era is the urban century, which they support with statistics about the estimated number of urban residents worldwide, the rate of increase in urban residents, the proportion of the world population considered urban, and the contribution of urban areas to domestic product, energy demand, and carbon emissions. These figures are viewed as challenges that necessitate efforts at sustainability and resilience. But the authors argue that the use of unclear or unnecessarily limited definitions of urban sustainability and urban resilience has created confusion, which can impede progress and solutions. The authors seek to clear up the confusion by offering a definition of urban resilience, which refers to “an urban system” [88] (p. 269). Urban or some form of the term appears nearly 100 times in the article.

This article emphasizes the importance of urban trends but lacks specificity about what the term urban means. The validity of statements about the number and increase in urban residents, the proportion of the urban population, and the contributions of urban areas all crucially depend on how urban is defined. But the article does not offer a definition of urban. Furthermore, an understanding of urban trends worldwide must address the fact that definitions of urban are not consistent across countries, as previously discussed. Given the emphasis on urban trends to motivate the paper, some discussion or explanation of what urban means might be expected, but the article does not provide any elaboration. It faces many of the same issues raised by other highly cited articles regarding the meaning of an urban system and subsystems. In addition, the authors’ proposed definition of urban resilience is missing any details about what constitutes an urban system. Later, the authors add that “resilience is a system property and not confined to a single scale of a city or even subsystem. Too frequently, the resilience concept has been applied to a specific urban systems’ scale with numerous attempts made to analyse [the] sustainability, or resilience, of individual cities and has often been constrained to either single or narrowly defined issues (for example, population, energy and security). These attempts are misleading: urban systems are open systems and have multiple scales from household to neighbourhood and from city to region” [88] (p. 269–270). The observation about scales seems consistent with other work related to urban resilience [89,90,91,92]. However, this observation is not enough to explain what is meant by urban or to distinguish it from the many other phenomena that involve multiple scales. The same concern applies to the description of urban systems as open systems.

Zhang and Li [93] argue for more clarity to differentiate urban resilience and urban sustainability. The paper suggests that urban resilience and urban sustainability have substantially overlapping meanings, but this overlap is a potential problem that could diminish and dilute both concepts. The authors point out what they see as some key differences between urban resilience and urban sustainability, including research trends (number of articles over time), research scale (global, regional, city, community, and facilities), and research clusters (ecological systems, infrastructure systems, and others). They use a specific physical infrastructure project in New York harbor to make the case that urban resilience and urban sustainability are potentially contradictory. The article offers a diagram to help clarify and distinguish the two concepts while offering new definitions of each. However, the proposed definition of urban resilience does not mention the term urban. This omission is especially noteworthy given that urban or some form of the term appears elsewhere in the article nearly 100 times.

The attempt to clarify urban resilience and urban sustainability appears to leave the meaning of urban unclear in the process. The authors’ proposed definition of urban resilience does not refer to the term urban at all; it is also so broad that it could apply to many other contexts that would not otherwise be considered urban. For example, the proposed definition could be equally used to describe other measurement categories like rural, town, and village, or other subjects of study including governments and other institutions and organizations. Furthermore, the article does not provide any explanation to distinguish urban resilience from non-urban resilience. The discussion of resilience does not appear to describe anything necessary to the concept of urban. It also raises the question of what is specifically urban about this definition of urban resilience. Accordingly, it is not clear what the concept of urban adds to the concept of resilience or vice versa. The authors’ proposed definition of urban sustainability mentions “the subsystems making up a city” [93] (p. 145), but this definition faces the same concerns raised about other articles regarding the lack of explanation about what the subsystems are or what a city is.

Additional articles that offer frameworks or models [94,95,96,97,98,99,100] similarly either refer to urban systems without offering an explanation or do not provide a description of what the term urban means.

4.3. Empirical Studies

Spaans and Waterhout [101] use a case study approach and describe the Rockefeller Foundation’s 100 Resilient Cities initiative. The motivation for the article is that cities worldwide face acute problems or shocks, like so-called natural disasters, and chronic problems or stresses, like resource shortages. The authors describe the City Resilience Framework, which is part of the Rockefeller Foundation’s 100 Resilient Cities initiative, with a focus on the case of Rotterdam as an example of applying this approach to resilience. The article also considers how ideas about resilience may have been influenced by Rotterdam’s participation in the program. The authors rely on the definition of urban resilience issued by the Rockefeller Foundation as part of its 100 Resilient Cities Program, which refers to “a city” [101] (p. 110). Urban or some form of the term appears more than 25 times in this short article.

The use of a definition of urban resilience provided by a philanthropic organization does not avoid concerns about meaning. The reference to a city in the definition raises its own set of questions, including how is a city defined and what constitutes a city. The authors raise a number of issues about the ways cities can be viewed, including as psychological systems, military systems, socio-technical systems, metabolic systems, other functional systems, open systems, a collection of networks, and “a jumble of overlapping and intersecting networks operating in parallel, both physical and non-physical” [101] (p. 114). But the article does not offer a resolution through the multiplicity of views. In fact, the authors ask, “what kind of system is a city and can practitioners grasp its inherent complexity?” [101] (p. 114) yet do not provide an answer. If this is an open question, then it also calls into question a definition of urban resilience based on a city.

Additional urban resilience articles use case studies [102,103,104,105,106,107,108,109,110,111,112,113,114], quantitative or qualitative approaches [11,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134], or some combination [135,136,137,138,139] but refer to urban systems without offering an explanation, use urban and cities interchangeably, or otherwise do not describe what the term urban means.

5. Discussion

Recent disasters and conflicts, including earthquakes in Afghanistan, Morocco, Syria, and Turkey, floods in China and Libya, and wars in Ethiopia, Somalia, Ukraine, and Yemen, have harmed millions of people, damaged infrastructure, and highlighted the vulnerability of cities around the world. These crises have also highlighted calls for resilience. Although the literature on resilience has expanded enormously and is increasingly widespread, the urban perspective remains underexplored.

The results from recent urban resilience articles demonstrate that the term urban is repeatedly invoked and prominently featured, its conceptual use is not identified, and the term is not clearly explained or defined. Many articles refer to urban in the form of urban systems but do not explain what urban systems are. Some of these articles name various kinds of urban systems, but these names are not accompanied by definitions to explain them or additional information that would distinguish them from other things that could also be considered urban systems. Other articles use the terms urban and city interchangeably but do not address what is meant by a city, what definition is used or intended, what criteria are chosen to identify a city, and what differentiates the terms urban and city.

The meaning of urban in these urban resilience articles is assumed to be clear, agreed upon, and understood without explanation. But urban is a complex and contested term. The various conceptual uses of urban found in the broader literature signal multiple interpretations and understandings. It might be the case that by focusing so much energy on describing and defining resilience, scholars have neglected the urban half.

The lack of clarity about the term urban in discussions of urban resilience is important for several reasons. At a basic level, the chosen conceptual use of urban influences how urban resilience should be understood, including the relationship between urban and resilience. Otherwise, it is unclear if urban resilience refers to a specific or unique form of resilience, the simple application of resilience to urban contexts, the kinds of resilience found in urban places, some combination of these, or something else entirely. The meaning and definition of urban also fundamentally affect how urban resilience is measured, implemented, and evaluated. The use or mixing of different conceptualizations of the term urban can lead to faulty comparisons of urban resilience characteristics, factors, and goals. Similarly, the lack of information about how urban is defined can result in misleading assessments about urban resilience capacity, development, and success.

5.1. Questions about Urban

These findings raise larger questions about the term urban that mirror concerns about the term resilience. Prior work has pointed out a series of probing questions about the concept of resilience in terms of who, what, when, where, why, and how [16,17,18,20,100,140,141,142,143,144]. This study suggests that the questions of who, what, when, where, why, and how also apply to the concept of urban in urban resilience. For example, who is counted (as living in an urban area or being part of an urban system), who does the counting, and who decides? Whose vulnerabilities and needs are prioritized and who is left out? What does the term urban mean and what constitutes being urban? What are the criteria for designating something as urban, and what differentiates it from non-urban things? When are urban criteria established and measured, which reflects the standards of the time, and when will they change? Where are urban areas located and where are the boundaries, i.e., where do they start and end? Why focus solely on urban (as opposed to city, metro, or regional, to name a few alternatives)? How is urban defined? How are urban aspects, e.g., urban systems, identified? How is urban used consistently? This preliminary list also suggests that some of the who, what, when, where, why, and how questions about resilience may stem from ambiguity about the meaning and use of the term urban.

Additional concerns about the concept of resilience also appear to be applicable to the concept of urban. For example, resilience is often undefined, descriptions of resilience are unclear or inconsistent or both, the ambiguity of resilience may be an advantage or disadvantage, and the value of using resilience as opposed to other concepts is in dispute [18,19,20,145,146,147]. (Indeed, the enthusiastic embrace, debates about meaning, and concerns about applicability mirror a similar process that played out with previous urban-related concepts [148,149,150,151].) Similarly, this paper shows that in the urban resilience literature, urban is often undefined, descriptions of urban are unclear or inconsistent or both, the ambiguity of urban may be an advantage or disadvantage, and the value of using urban as opposed to other concepts is in dispute.

Urban concepts and definitions also matter because they can influence, or even determine, who is included and excluded. After all, the history of urban activity is also a history of marginalizing groups based on income, class, race, ethnicity, color, gender, immigration status, sexual orientation, and other identities. Political decisions can intentionally or unintentionally leave some groups out of the urban resilience planning process. These groups may find their voices are not heard or even ignored. These exclusionary processes may burden marginalized groups with the harmful consequences as well as deprive them from the benefits. Considerations of equity and justice in urban resilience [1,152,153,154,155] would demand a critical reappraisal of what urban means for urban resilience.

5.2. Applying Urban Concepts

These observations indicate the need for more careful attention to addressing what urban means for urban resilience. Conceptual uses of the term urban in other fields may be instructive for urban resilience scholarship and practice.

If urban is treated as a subject, one broad implication is that urban for urban resilience is simply about a shared, common subject of study. A conventional view would suggest that urban resilience is about cities as they have been traditionally known and understood—at least through the lens of economics. It would also suggest that there are some universal aspects of cities, in other words, that defining components of cities are the same everywhere. If this view of urban is adopted for urban resilience, it would mean that urban resilience is about the resilience of cities, which are identified by the presence of agglomeration and a particular interrelationship between land use, location, and human interaction. This view implies a somewhat fixed, static notion of a city that privileges economic activity.

However, the conventional view might be parochial in endorsing a Western or global North perspective that creates artificial hierarchies. One possible implication of this view of urban for urban resilience is that current discussions of urban resilience might be misguided because they rely on a fundamentally skewed and incomplete view of which cities to consider. This suggests that urban resilience is about the resilience of a broader set of cities than might otherwise be considered under the conventional notion of cities. Another possible implication is that the standards for evaluating the urban resilience of a given place must be reconsidered in light of the wide variety of cities, and differences between them, and should not be benchmarked against a small set of global North cities.

An alternate view implies a notion of urban that reaches far beyond the boundaries of cities described previously. The implications for urban resilience are unclear, but one possibility is that urban resilience is interdependent with global resilience such that urban resilience for one place cannot be separated from the resilience of other places. At one extreme, the work of Castells [35] would imply that urban resilience is nothing more than resilience. In other words, adding urban to resilience does not actually add anything.

If the concept of urban as a condition is adopted for urban resilience, it would imply that aspects of the urban environment may affect risks and approaches to resilience for residents. Furthermore, urban influences on life are not limited to cities, which is in contrast with the conventional view of urban as a subject of study. According to this approach, experiencing urban as a condition can shape social relationships. This suggests that the urban condition will influence how societies formulate and adopt resilience plans. It may also influence a population’s capacity to be resilient.

If the concept of urban as a measurement category is adopted for urban resilience, it would imply that urban resilience refers to the resilience of those places designated as being urban according to government agency or non-governmental organization criteria. This view of urban would be associated with established and demarcated boundaries for the area of urban resilience. But it still leaves open questions of which indicator or set of indicators to use, why these indicator(s), and consistency across and within countries and time.

5.3. Urban Reconsidered

What is urban about urban resilience? What aspects of urban resilience are distinctly and uniquely urban, and how are they distinctly and uniquely urban? One possibility is that the uses of urban in discussions of urban resilience may change. For urban resilience, the conceptualization of urban may depend, in part, on the nature of the challenge or threat posed. For example, the destructive power of a hurricane may bring to mind the typical spatially or geographically bounded notion of an urban area. The threat of drought due to climate change might encourage a conceptualization of urban that extends beyond the commonly accepted boundaries of urban areas and explicitly recognizes relationships and interdependencies with rural or uninhabited places. Pandemics like COVID-19 may refocus urban resilience on conditions, including the density of social interactions that increase the risk of infection and disease transmission. Urban resilience in response to technological change, such as video conferencing that makes co-location less important, may emphasize urban as the agglomeration of economic activity. But if the intended meaning of the term urban shifts based on the situation, then urban resilience scholars should make this clear.

The number of issues and questions raised about the term urban may appear daunting and suggest that progress on the concept of urban resilience might be at risk. An idea from complexity theory can provide some direction to help think about ways out of this dilemma. Simulated annealing is a method that models the process of exposing a physical material to high heat and then gradually lowering the temperature to reduce defects. An example is hill climbing with error, which refers to a process of seeking the highest location on a physical landscape [156]; see Figure 3.

We can also think of this as the best vantage point on a conceptual landscape. If a simple rule is followed—for example, take a step in any direction unless the step leads to a lower height—then we might find a location that is high relative to the local surroundings. However, we might be stuck in this location despite the existence of higher points farther away that can only be reached by traversing a valley. If the rule is adjusted so that some number of steps can be taken to lower heights, it might be possible to eventually reach a higher vantage point.

The review of the recent urban resilience literature indicates there is some coalescence around notions of urban resilience, even if there are many different disciplinary perspectives and scholarly opinions. In this context, asking questions about what urban means for urban resilience could be viewed as an obstacle to progress and even moving in the wrong direction. However, the example of simulated annealing might be instructive. Thinking about urban resilience might need to take a few steps back in order to move forward. Conceptually, this might mean reconsidering what urban is and what urban means for urban resilience. For practice and implementation, this might mean urban areas moving to a slightly worse state in order to bounce back better. Re-examining what urban means and more carefully describing it could lead to deeper understanding, improved planning, and more effective implementation related to urban resilience.