Introduction

Abstract

This book takes up a topical issue in spatial planning, land use policy, housing studies, and sustainable urban geography—the fight against urban sprawl leading to new urban densification strategies—and interrogates the consequences of densification from the perspective of its impacts on social sustainability. Such an analysis is absolutely necessary considering that the arguments in favor of densification have so far relied mostly on discourses of ecological and economic sustainability. However, planners, policymakers, and urban practitioners cannot avoid the question of the social dimension of densification, if only to secure the social acceptance of densification objectives without which implementing densification will quickly become very difficult. This chapter announces the research objectives and clearly formulates the general question, which is then broken down into three sub-questions.

1.1 Push Towards Urban Densification in Cities Worldwide

Providing shelter for a global population that is urbanizing quickly presents a critical human development challenge. By 2030, it is estimated that almost five billion of us will be living in cities, constituting around 60% of the world’s population. Rapid urbanization is linked to numerous socio-environmental concerns such as concentrated use of energy and air pollution with significant impacts on human health, infrastructure, and economic prospects (UN, 2018). Facing these challenges has resulted in a myriad of solutions being proposed, and the list of possible urban forms within which dwellers can be housed sustainably is long and growing. High up on this list is the “compact city”, which has been introduced as a promising way to meet the challenges of a growing urban population for a considerable time (e.g. Newman & Kenworthy, 1999).

1.2 Rise of the Compact City Model in International Policymaking

The “compact city” (in the US also termed “new urbanism” or “smart growth”, “Stadt der kurzen Wege” in Germany) is a concept that evolved in the UK during the 1960s as parts of wider efforts to combat resource depletion (for discussion see e.g. Holden, 2004; Kahn, 2000). The authors of these studies argue that compactness of the built environment—generally defined as an increase in the density of units within city boundaries (Boyko & Cooper, 2011: 47)—would slow down urban sprawl in order to limit settlement expansion and ensure sustainable urban growth.

More precisely, many advantages of the compact city model have been highlighted in the past few decades. They include, for instance, the conservation of the countryside (Elkin et al., 1991); the protection of environmentally vulnerable landscapes (Dieleman & Wegener, 2004); less need to travel by car, thus reducing fuel, energy, and air emissions (Ewing, 1997); the support for public transport, walking, and cycling modes of mobility (Squires, 2002); better access to services and facilities, along with more efficient utility and infrastructure provision (Frey, 1999); as well as increased potential for revitalization and regeneration of inner urban areas (Kahn, 2000). The compact city has become a physical response to many urban challenges, such as land consumption, energy and resource waste, accessibility, and air pollution. It has practically evolved as a synonym for “the sustainable city” (Neuman, 2005: 17).

Indeed, many international organizations, politicians, and urban practitioners have agreed with the benefits proposed and started to introduce “densification” as a legally binding policy objective (e.g. UN Declaration on Environment and Development 1992,¹ Principles 4 and 15). Densification (also termed “intensification” or “consolidation”) is the process through which the compact city model is attained physically. A useful definition of the term can be found in Broitman and Koomen (2015: 32) who define densification as “a process leading to an increase in the number of households within existing municipal boundaries”. The process creates an increase in exploitation or use density—defined as the number of persons per square meter (Boyko & Cooper, 2011: 47)—in order to reduce individuals’ overuse of natural resources, such as land, water, or energy (Holman et al., 2015). Densification is thus widely assumed to play a decisive role in the sustainable transformation of settlements.

1.3 Densification Evokes Social Exclusion and Gentrification in Housing

However, by the mid-1990s, multiple studies (e.g. Breheny, 1997; Cernea, 1993; Gordon & Richardson, 1997; Jenks et al., 1996) claimed that the process of implementing densification—next to its potential environmental benefits—would threaten the quality of life, particularly in regard to social aspects and the conditions of the poor (for discussion, e.g. Daneshpour & Shakibamanesh, 2011). The critique of the compact city concept focused on claims arguing that densification has undesirable social consequences. Those consequences include affordable housing shortage, residential displacement, and social exclusion as a direct consequence of (re)development and upgrading.

More precisely, densification has been accused of posing a threat to the very existence of social sustainability in housing, which focuses on various dimensions, such as social mixing, inclusion, residential stability, or neighborhood cohesion (see Section 3.3 for details). It can subsequently lead to unfair distribution of power and resources, freedom, access to decision-making, and general capacity-building (for discussion see e.g. Williams et al., 2000; Whitehead, 2003). Social sustainability in housing is generally defined as given if housing development “is compatible with harmonious evolution of civil society, fostering an environment conductive to the compatible cohabitation of culturally and socially diverse groups while at the same time encouraging social integration, with improvements in the quality of life for all segments of the population” (Polese & Stren, 2000: 1516) (for a detailed definition of the concept, Chapter 3.3).

While some approaches have pointed out the gentrification and displacement effect of densification on local residents and activities (Chiu, 2003; Lees, 2000), or the risk of weaker social ties in higher density environments (Freeman, 2001), others have examined the exacerbation of social exclusion of particular groups within local communities (Gosling, 2008) as well as the accumulation of residents’ low skill jobs as results of displacement (Law, 2002). In addition, Williams et al. (2000) conducted research on the social sustainability of housing areas where development has been densified. Their often-quoted study concluded with claims that densification would result in a reduction of private space, smaller houses, and gardens, or no gardens at all. Moreover, more intensive traffic causes potential negative environmental impacts, such as air pollution, noise, and a generally poor environment for cyclists and pedestrians, as well as increase in potential “bad neighbor” effects, such as noise, disturbance, or litter (Williams, 2010).

In essence, the main argument against the compact city was and still is that densification leads to residents’ social exclusion because there is an increase in housing prices and rents when real estate stocks are rebuilt and modernized. Although densification enables more apartments on the same parcel to be constructed, implementation tasks increasingly take place in the format of redevelopment of existing stocks e.g., through subdivision, extension to existing buildings, or total replacement construction since free inner-city urban green and brownfields are overbuilt already (Touati-Morel, 2015).

The result of such densification activities (e.g., renovation, subdivisions, replacements) within urban boundaries is that new housing is (re)built with higher densities—but also land prices and rents (Davidson & Lees, 2005). Newly built densified housing is thus often only accessible to certain—mostly high-income—groups of the population (Hackworth & Smith, 2001). Consequently, an increasing number of people worldwide is suffering from rising housing prices and rents as results of new-built densification (Aalbers & Christophers, 2014; Aalbers, 2017; Christophers, 2022). Affordable housing shortage and residents’ social displacement have thus become severe societal problems in many cities globally (Rolnik, 2013; Wicki et al., 2022). Particularly lower income segments are forced to leave the city centers for cheaper suburban areas as they can no longer afford a dwelling in recently densified areas (Lees, 2008). Such social exclusion scenario, however, is considered highly unsustainable.

Social exclusion in turn is a process through which the composition of inhabitants changes, particularly due to the inflow of higher income groups and the (in)direct displacement of lower income groups, which in turn cause gentrification, social segregation, and social polarization (Lees, 2008: 2463). Hence, the result is that lower income residents living in these neighborhoods are forced to leave the center for cheaper suburban areas as they can no longer afford a dwelling in recently densified areas (Marcuse, 1985: 207). A vicious circle is created “in which the poor are continuously under pressure of displacement and the wealthy continuously seek to wall themselves within gentrified neighborhoods” (Marcuse, 1985: 196).

Dwellers deprived of housing in the center, and who are pushed to the margins of cities, struggle to find alternative housing in the city center. This is because they can no longer afford the rent after densification occurs. They are thus forced to move to the agglomeration areas, where rents are lower. This process may finally cause low-income groups to lack control over the most basic components of life—which are the places they call home (Slater, 2009: 307). Such a scenario is considered highly unsustainable (Jenks et al., 1996: 84). Hence, through densification, the solution to one problem (natural resource consumption) causes another problem (social exclusion) instead.

1.4 Research Gap: Politicizing and Identifying Densification as a Governance Challenge

In summary, an intense debate has been ongoing for more than forty years over the supposed environmental advantages of the compact city. That debate is also about the potential drawbacks of densification for different categories of stakeholders, particularly those of lower income. Whereas until the 1990s, development on greenfield outside city boundaries was largely promoted by policymakers and urban practitioners (for discussion, Filion, 2015), the land use conditions have changed under the compact city model. Land use interests cannot continue to be generously realized because unbuilt land is no longer available unlimitedly. Instead, implementing densification objectives implies that the needs and visions of different individuals and groups clash at the very same locations within the urban built environment.

The policy shift towards densification has made conflicting use interests more pronounced because stakeholders now must deal with each other in a context of scarce urban land. This implies that they must negotiate for their interests within the already built environment and within existing city boundaries. Implementing densification policy objectives becomes a complicated process because the objectives are embedded in a tight web of already existing, diverse, and contradictory rights, claims, and duties. What benefits one stakeholder potentially hurts another. A landlord’s profits through (re)development or upgrading might come at a tenant’s expense. High-rise construction might cast shadows on neighboring land. And accessibility for one is pollution or loss of security for others. Apart from potential ecological benefits, densification produces both advantages (e.g. increased housing options, and business opportunities) and disadvantages (e.g. rising noise or rents through costly upgrading of settlements, loss of green surfaces, or view) for different individuals, firms, or households.

This book identifies the socio-political challenges of implementing densification objectives, rather than considering the process as a technological, architectural, or design-based problem (see previous densification literature e.g. Bibby et al., 2018; Broitman & Koomen, 2015; Kyttä et al., 2013). The point of departure is that densification per se does not necessarily lead to sustainable outcomes in terms of social inclusion or community stability. Rather, how it is planned, implemented, and governed by the actors involved is what matters. Stated another way, the research gap this book addresses is to politicize densification. This is done by identifying the actors involved, their objectives, their strategies, as well as the socio-political structures (i.e. rules, laws, policies) that govern densification that try to prevent rivalries among competing groups and unsustainable social outcomes in housing, such as exclusion, gentrification, discrimination, or displacement.

1.5 Research Objectives and Questions

The overarching goal of this book is to examine, both theoretically and empirically, the different mechanisms that govern the implementation of densification objectives and its impact on housing uses, actor’s strategies, as well as the impact densification has on social sustainability in housing (see Sect. 3 for more details).

Theoretically, this book aims to contribute to actors-centered neoinstitutionalist political ecology research (see Section 2) by analyzing how different (public and private) actors govern densification with regard to housing, and by focusing clearly on the social dimension of housing development. In addition, this book more than ever before aims to connect housing challenges to densification and land policy debates (e.g. Davy, 2012; Kolocek, 2017), as well as to social sustainability concerns (e.g. Bramley et al., 2009; Burton, 2000; Chiu, 2004). Considering future challenges of land scarcity that currently evolve in many cities globally, the findings of this research may help governments, practitioners, and planning professionals to cope with rising rental prices, exclusion, displacement, and social challenges in cities. Understanding the conditions for the success or failure of socially (un) sustainable implementations of densification objectives is an important step to overcoming barriers and to supporting policymakers and planning practitioners who promote more socially inclusive outcomes.

Empirically, research questions (see below) are answered by adopting a qualitative research design that is able to capture the origins of socio-political structures, human behavior, and decision-making (Sect. 4). Empirical research is done in Switzerland, a country that has been strongly challenged by rising housing use conflicts as results of densification in recent years, particularly in cities. While for the past twenty years much quantitative research in Switzerland has been employed to measure the impacts of urban sprawl (e.g. Grams & Nebel, 2013; Schwick et al., 2012), specifically on the quantitative effects of certain policy measures such as urban growth boundaries (e.g. Gennaio et al., 2009; Klaus, 2019; Weilenmann et al., 2017), this book aims to contribute to the work of fellow scholars who endeavored to analyze densification as a governance-oriented challenge from a qualitative research perspective (Balmer & Gerber, 2017; Devecchi, 2016; Hengstermann, 2019; Hersperger et al., 2014; Nabielek, 2011; Nicol, 2013; Nicol & Knoepfel, 2008; Rérat, 2012; Rudolf et al., 2018).

One overarching and three analytical research questions underlie this book. They are explained in more detail in the chapters that follow (Figure 1.1).

Fig. 1.1

Schematic overview of the different elements and sections of this book

RQ: What governance mechanisms lead to socially sustainable housing development in a densifying city?

• SQ1: How do institutional rules affect the outcomes of densification in terms of social sustainability in housing?

• SQ2: What use strategies do actors (owners and non-owners) follow to contribute to socially sustainable housing in a densifying city?

• SQ3: How does the implementation of densification objectives impact socially sustainable housing outcomes?

In the following sections, the theoretical background and analytical framework that I used in this book to answer the research questions are introduced (Chapter 2). In Chapter 3, the value added by the neoinstitutionalist political ecology approach is explained for the study of social challenges in housing and in a context of densification. In Chapter 3, in addition, the theoretical concepts of the analytical framework with regard to housing are explained in more detail. Particularly, the three main theoretical concepts this book is built on are introduced—housing as a resource, institutions, and actors’ strategies—that help to answer the research questions. As demonstrated in the sections to come, these three blocks cannot be separated from each other as it is exactly the relationship that binds them—the governance mechanisms—which provides valuable insights into how actors involved in densification procedures govern housing socially sustainably (Chapter 3.1 to 3.6). In Chapter 4, I then introduce the study design and the geographical context of the empirical analysis (Chapter 4) and describe the structure of the four articles constituting this book (Chapter 5).