3.1. Definitions of sustainability transformation

The studies reviewed used heterogeneous definitions and theories in framing the questions, or focused on conceptual debate as the main content. Not all articles used the exact concept of sustainability transformation: some used a synonym. For example, Ernst et al. (Reference Ernst, de Graaf-Van Dinther, Peek and Loorbach2016) use the term ‘sustainable urban transformation’, which they define as a subset of urban sustainability transitions. Several articles did not explicitly define what they mean by sustainability, and even fewer defined how they operationalize the concept of transformation as an empirically measurable phenomenon. Martínez et al. (Reference Martínez, Boas, Lenhart and Mol2016), for example, define sustainability based on practical measures (i.e., sustainability prizes).

None of the articles stated that the current levels of natural resource use are sustainable. Both the social and biophysical dimensions of sustainability transformation were recognised, often with one emphasized more than the other. In general, discussions on environmental sustainability mainly consisted of naming one wicked problem (e.g., climate change; Princiotta & Loughlin, Reference Princiotta and Loughlin2014); listing several wicked global environmental problems; adding smaller-scale problems to the list, such as deforestation and desertification (Pant et al., Reference Pant, Adhikari and Bhattarai2015); explaining the threat of planetary boundaries being breached (Barau et al., Reference Barau, Stringer and Adamu2016); and highlighting the importance of securing ecosystem services (Chapin et al., Reference Chapin, Mark, Mitchell and Dickinson2012). Social sustainability, on the other hand, was less frequently defined, but could be seen as having two main components: current and intergenerational global equity (Pickett et al., Reference Pickett, Boone, McGrath, Cadenasso, Childers, Ogden and Grove2013). Unsustainability dynamics were presented, for example, via the dominating impact of humanity on the global biophysical system (Olsson et al., Reference Olsson, Moore, Westley and McCarthy2017), or by societal dynamics and power relations as drivers of the use of biophysical resources (Pichler et al., Reference Pichler, Schaffartzik, Haberl and Görg2017), or by increasing population levels and energy-intensive lifestyles (Princiotta & Loughlin, Reference Princiotta and Loughlin2014). The dimensions of sustainability transformation studied in the articles reviewed varied greatly, including (but not exhaustively) processes of change, example sectors, lifestyles, design principles, technologies and quantifiable magnitudes of change.

Studies frequently referred to articles from two or more theoretical origins. Some papers combined social and economic elements with ecosystems (e.g., Olsson et al., Reference Olsson, Moore, Westley and McCarthy2017). In general, the resilience approach emphasizes the connection between nature and society within the planetary safe operating space, whereas ecological limits are not as well incorporated into socio-technical transition approaches (Olsson et al., Reference Olsson, Galaz and Boonstra2014). Patterson et al. (Reference Patterson, Schulz, Vervoort, van der Hel, Widerberg, Adler and Barau2017) described how emerging hybrid narratives can define planetary boundaries as the ceiling and social boundaries as the foundation of sustainability transformation, referring to Leach et al. (Reference Leach, Rockström, Raskin, Scoones, Stirling, Smith and Olsson2012, Reference Leach, Raworth and Rockström2013). The social endpoint of a sustainability transformation is seemingly harder to define than the ecological endpoint, even though social aspects were often mentioned when the definition focused on ecological aspects. The definition of sustainable urban transformation in Ernst et al. (Reference Ernst, de Graaf-Van Dinther, Peek and Loorbach2016) focused on social aspects: processes of change, sustainable places and normative societal goals as components of sustainable urban transformation. The magnitude of the social aspects of sustainability challenges was often seen to be dependent on the chosen starting point, and sustainability was highlighted as having an unequal distribution and not being unambiguous (meaning the existence of plural sustainabilities) or being contested (e.g., Patterson et al., Reference Patterson, Schulz, Vervoort, van der Hel, Widerberg, Adler and Barau2017). Reaching a consensus on long-term sustainability goals among stakeholders is also one of the greatest challenges in practise (Chapin et al., Reference Chapin, Mark, Mitchell and Dickinson2012).

The end goal of sustainability varied in its relation to the current economic system. Sustainability transformation discourses commonly criticize unlimited economic growth: for example, Beling et al. (Reference Beling, Vanhulst, Demaria, Rabi, Carballo and Pelenc2018, p. 306) argue that “the quest for unlimited growth as equated with progress is generally contested by all transformation discourses, as are Western materialism, anthropocentrism, the destruction of the commons, and blind faith in science and technology.” In contrast, in studies that focus on local sub-city-level sustainability projects, economic development is a part of the definition of sustainability (Daneri et al., Reference Daneri, Trencher and Petersen2015; Ernst et al., Reference Ernst, de Graaf-Van Dinther, Peek and Loorbach2016).

It was often difficult to separate all of the theoretical approaches to which the articles related. Justification for the selection of theories, if made explicit, was based on, for example, “prominent conceptual approaches” (Patterson et al., Reference Patterson, Schulz, Vervoort, van der Hel, Widerberg, Adler and Barau2017, p. 5) or “current visibility and their catalytic character in broader development-critical debates and networks” (Beling et al., Reference Beling, Vanhulst, Demaria, Rabi, Carballo and Pelenc2018, p. 305). Some articles compared theoretical approaches or combined concepts from different origins (e.g., see Beling et al., Reference Beling, Vanhulst, Demaria, Rabi, Carballo and Pelenc2018, human development, degrowth and buen vivir; see Olsson et al., Reference Olsson, Moore, Westley and McCarthy2017, Anthropocene, social innovation and transformations to sustainability; and see Patterson et al., Reference Patterson, Schulz, Vervoort, van der Hel, Widerberg, Adler and Barau2017, socio-technical transitions, social-ecological systems, sustainability pathways and transformative adaptation). Frequently used approaches were socio-technical transitions and socio-ecological transformations, as well as leverage points (Abson et al., Reference Abson, Fischer, Leventon, Newig, Schomerus, Vilsmaier and Lang2017).

Like Patterson et al. (Reference Patterson, Schulz, Vervoort, van der Hel, Widerberg, Adler and Barau2017), we also observed a distinction between sustainability as a normative goal and as an observable phenomenon. For example, Fischer et al. (Reference Fischer, Peters, Vávra, Neebe and Megyesi2011) take an approach that is more analytical than normative. However, most articles took a normative approach by stating that sustainability transformation is needed. Princiotta and Loughlin (Reference Princiotta and Loughlin2014), for example, state that preventing catastrophic climate change is a monumental challenge and fundamental changes in energy generation and use are necessary. Haberl et al. (Reference Haberl, Fischer-Kowalski, Krausmann, Martinez-Alier and Winiwarter2011) also argue that a new socio-metabolic regime is required. The normative element of the social dimension of sustainability is highlighted by Pickett et al. (Reference Pickett, Boone, McGrath, Cadenasso, Childers, Ogden and Grove2013), who state that “sustainability is a normative social goal, resulting from a civic dialog, and suggesting processes of change toward that goal.” Real-life sustainability transformation experiments were often normative (Weiland et al., Reference Weiland, Bleicher, Polzin, Rauschmayer and Rode2017). Li (Reference Li2009) states that transformation is inevitable because climate stabilization is not compatible with the growth requirement of capitalism.

Some articles listed success factors for a sustainability transformation. Krellenberg et al. (Reference Krellenberg, Koch and Kabisch2016) argue that “it is the combination between political will and local, people-centred approaches that drives the success of urban sustainability transformations.” Patterson et al. (Reference Patterson, Schulz, Vervoort, van der Hel, Widerberg, Adler and Barau2017, p. 4) further contend that “perhaps governance for sustainability transformations entails a dual focus on high-level, longer-term transformation combined with an honest recognition of the realities of near-term incrementalism at the same time. That is, a strategy of incremental change with a transformative agenda, where a normative focus on sustainability transformations helps to orient incremental efforts (such as policy change) within a broader narrative of transformative change.”

Many of the articles reviewed presuppose that the intention of sustainability transformation studies is to contribute to the actual change, not only to study, assess or measure it. Patterson et al. (Reference Patterson, Schulz, Vervoort, van der Hel, Widerberg, Adler and Barau2017) question whether the notion of transformation is useful for steering transformation or could be better used to describe change ex post. Many of the articles advocate transdisciplinarity (in the sense of involving non-scientific actors; e.g., building transformative capacity, engaging stakeholders in research, etc.) as an approach to achieving transformation rather than as an approach for assessing whether transformation happens (Krellenberg et al., Reference Krellenberg, Koch and Kabisch2016; Ritz et al., Reference Ritz, Scheurer and Schurer2001; Trencher et al., Reference Trencher, Yarime and Kharrazi2013; Wolfram et al., Reference Wolfram, Frantzeskaki and Maschmeyer2016).

3.2. Scales of sustainability transformations

In terms of the geographical scale, we noted, similarly to Beling et al. (Reference Beling, Vanhulst, Demaria, Rabi, Carballo and Pelenc2018), that transformation discourses envision a global-level change, whereas existing ‘sustainable living’ projects are typically local experiments. Global degradation of the environment is an aggregate of local or regional processes and can be reduced by transformations at these levels (Chapin et al., Reference Chapin, Mark, Mitchell and Dickinson2012). In the empirical articles reviewed, the geographical scale varied from a part of a city, to an entire city, to the regional, multinational and global levels. Several articles had a specifically urban focus (e.g., Higgins, Reference Higgins2013; Krellenberg et al., Reference Krellenberg, Koch and Kabisch2016). Some articles without an urban focus discussed aspects related to urbanization: for example, Chapin et al. (Reference Chapin, Mark, Mitchell and Dickinson2012) discuss the implications of urbanization for residents’ sense of place. Some of the empirical articles covered several locations or compared individual cases. For example, Fischer et al. (Reference Fischer, Peters, Vávra, Neebe and Megyesi2011) study citizens’ views on governance approaches to stimulate behavioural change in several European countries.

Interestingly, even when the cases were local, biophysical limitations were discussed at the planetary level, rather than at the scale of the study itself (Barau et al., Reference Barau, Stringer and Adamu2016). Olsson et al. (Reference Olsson, Galaz and Boonstra2014) question the connections between multiple levels, asking how niche experiments can have an impact at the scale of global challenges, and they see the possibility of answering these questions by combining transition management and resilience theory. Different theoretical approaches have different strengths and weaknesses in studying the scales of transformations. Pant et al. (Reference Pant, Adhikari and Bhattarai2015) discuss how climate change adaptation scholars account for space and place in local contexts of developed as well as developing countries in more detail than transition scholars. They contend that transition scholars focus on examples from developed countries, which tend to be urban-centric, and examine long-term sectoral transitions that cross spatial boundaries.

The scale of social organization also features in a number of studies. Some interesting questions were raised as to whether pre-existing initiatives and institutions can steer transformations (Olsson et al., Reference Olsson, Moore, Westley and McCarthy2017; Pichler et al., Reference Pichler, Schaffartzik, Haberl and Görg2017) and regarding the stability versus change of institutions (Abson et al., Reference Abson, Fischer, Leventon, Newig, Schomerus, Vilsmaier and Lang2017). Westley et al. (Reference Westley, Olsson, Folke, Homer-Dixon, Vredenburg, Loorbach and van der Leeuw2011) consider innovations at multiple institutional scales and conclude that institutions are required to set the conditions for innovations to contribute to broad societal challenges.

Different theoretical approaches have different typical timescales (e.g., less than a decade for innovation; Olsson et al., Reference Olsson, Moore, Westley and McCarthy2017). Transition and social-ecological system approaches take a conceptual orientation to trajectories of change over time: sustainability pathways and plural and emancipatory orientations in transformational adaptation (Patterson et al., Reference Patterson, Schulz, Vervoort, van der Hel, Widerberg, Adler and Barau2017). Weiser et al. (Reference Weiser, Lutz, Lang and Kümmerer2017) propose a time ecology approach, because temporal dynamics are often not explicitly considered or conceptualized in sustainability transformation research, even though “transformation processes are understood to be context-specific developments that happen over a specific period of time” (Weiser et al., Reference Weiser, Lutz, Lang and Kümmerer2017, p. 275). Patterson et al. (Reference Patterson, Schulz, Vervoort, van der Hel, Widerberg, Adler and Barau2017) discussed the challenges of identifying a start and an end point of a transformation.

The temporal scale of empirically assessed sustainability transformations varied between millennia, decades, years and weeks, and from historical perspectives to the current situation and future projections. The year 2050 was used as a cut-off for several simulations, whereas Harich (Reference Harich2010) used a relative time period of 500 years. Importantly, we found no empirical cases that measured the process of change over time explicitly. Articles did, however, present a time series (e.g., Higgins, Reference Higgins2013), descriptions of change over time (e.g., Haberl et al., Reference Haberl, Fischer-Kowalski, Krausmann, Martinez-Alier and Winiwarter2011) or projections into the future (e.g., Princiotta & Loughlin, Reference Princiotta and Loughlin2014). While no articles assessed change over time, they nevertheless highlighted the importance of considering sufficiently long time periods, intergenerational timescales in policy and the durability needed for transformational innovations, as well as other aspects related to time. Many articles measuring or describing transformations naturally focused on the past (e.g., Ernst et al., Reference Ernst, de Graaf-Van Dinther, Peek and Loorbach2016; Martínez et al., Reference Martínez, Boas, Lenhart and Mol2016), although there was also a view that transformation is ongoing (Burns, Reference Burns2011).

3.3. Assessing sustainability transformations

Only four of the articles reviewed assessed sustainability transformation, and an additional 12 articles did this partially (Table 3). Both qualitative and quantitative assessments of the varying dimensions of sustainability transformation were used, and many articles used both. In addition, both comparative and similar cases were used. Those articles that had assessed sustainability transformation used the following methods: case studies (Ernst et al., Reference Ernst, de Graaf-Van Dinther, Peek and Loorbach2016; Martínez et al., Reference Martínez, Boas, Lenhart and Mol2016), multiple case studies (Chapin et al., Reference Chapin, Mark, Mitchell and Dickinson2012) and lifestyle archetypes coupled with ecological footprint analysis (Moore, Reference Moore2015). In addition to the methods mentioned, articles that partly measured sustainability transformation used, for example, scenarios, narratives, quantitative reviews, macro-level empirical analyses, interviews and simulations. What had been assessed and what data were used varied from article to article (Table 3).

Table 3. Empirical articles reviewed and a summary of their content related to the first three research questions.

WWF = World Wide Fund for Nature.

While we argue that the novelty of this article is to focus on the assessment of sustainability transformations, there were articles that questioned the rationality and measurability of a sustainability transformation altogether. For example, Schlaile et al. (Reference Schlaile, Urmetzer, Blok, Andersen, Timmermans, Mueller and Pyka2017) state that stakeholders have differing visions and expectations of a transformation. Patterson et al. (Reference Patterson, Schulz, Vervoort, van der Hel, Widerberg, Adler and Barau2017) question whether we can observe when transformations are occurring and reflect on the relationship between incremental change and longer-term transformation (meaning decades). Weiland et al. (Reference Weiland, Bleicher, Polzin, Rauschmayer and Rode2017, p. 32) specify that: “As no blueprint of a sustainable society exists … the challenge is to define the shape of a sustainable society (target knowledge), as well as the process of achieving it (transformation knowledge).” Similarly, Olsson et al. (Reference Olsson, Moore, Westley and McCarthy2017) specifically state that scaling out, up (institutional structures and processes) and deep (values, beliefs, etc.) are all required for a transformation, and that these cannot only be measured numerically. However, system knowledge – the knowledge of the functioning and causal links within natural (or social) systems – is a common target of natural science (Weiland et al., Reference Weiland, Bleicher, Polzin, Rauschmayer and Rode2017).

Weiland et al. (Reference Weiland, Bleicher, Polzin, Rauschmayer and Rode2017) discuss characteristics of sustainability experiments, observing that social actors other than scientists often design and evaluate outcomes, and they note that, as a consequence, failure and unexpected outcomes are seldom addressed. Abson et al. (Reference Abson, Fischer, Leventon, Newig, Schomerus, Vilsmaier and Lang2017) propose a research agenda, namely the realms of deep leverage for sustainability transformation: restructure (institutions), reconnect (interaction between people and nature) and rethink. Several articles propose combining research traditions or research methodologies from at least two fields (Olsson et al., Reference Olsson, Galaz and Boonstra2014; Pichler et al., Reference Pichler, Schaffartzik, Haberl and Görg2017).

3.4. Have sustainability transformations taken place?

The 16 empirical articles identified signs of a sustainability transformation not happening, a level of deteriorating sustainability or an ongoing sustainability transformation. Whether the articles had identified an existing sustainability transformation relates closely to how they had defined what a sustainability transformation is.

Ernst et al. (Reference Ernst, de Graaf-Van Dinther, Peek and Loorbach2016) found that sustainability was not achieved during a certain target period in Rijnhaven, The Netherlands. Existing discourses on sustainability can hide unsustainability problems and prevent institutional change, such as in the city of Curitiba in Brazil (Martinez et al., Reference Martínez, Boas, Lenhart and Mol2016). Here, the authors explain that at least some level of sustainability had existed before the relative deterioration in Curitiba in the past.

Moore (Reference Moore2015) explains, for example, how much the average consumption in selected countries exceeds the global ecological carrying capacity and how large the transformations should be in different sectors in countries with different levels of resource use, quantitatively speaking. These sectors cover ecological footprint, carbon footprint, food, buildings, consumables, waste, transportation and water. Higgins (Reference Higgins2013) states that “none of the proposed actions from Hong Kong and London amount to a radical ecological change but merely a shift towards refining existing lifestyles with renewable energy, waste management and waste reduction and re-use strategies.” Fischer et al. (Reference Fischer, Peters, Vávra, Neebe and Megyesi2011) explain possible reasons for this and potential solutions: their interviewees described the societal context in industrialized countries as consumption-orientated, individualized and globalized, which means that top-down approaches such as regulations, increased prices and educational campaigns organized by government to shape the behaviour of the younger generations were thought to work towards achieving societal change. However, Fischer et al. (Reference Fischer, Peters, Vávra, Neebe and Megyesi2011) added that this might be a discursive strategy to defend one's own inaction.

There are no sustainable cities in the sense that they need resources and supporting ecological processes outside their borders, but a city can become more sustainable (Pickett et al., Reference Pickett, Boone, McGrath, Cadenasso, Childers, Ogden and Grove2013). Chapin et al. (Reference Chapin, Mark, Mitchell and Dickinson2012) presented case studies from New Zealand, showing that potential or actual transition to a more sustainable situation was achieved by stewardship emerging from a strong sense of place. In general, achieving or assessing sustainability in many possible dimensions simultaneously proved to be difficult. In the Oberlin project, the achievement of a sustainability transformation revealed challenges in creating a greenbelt, as well as in spurring economic development, while success was achieved with regards to carbon neutrality commitments, increasing alternative energy sources and renewables and sustainability education (Daneri et al., Reference Daneri, Trencher and Petersen2015). Notably, Burns (Reference Burns2011) argues that an organic sustainability revolution is already taking place at a moral–cognitive level, in practises and at an institutional level, and that it is visible in, for example, greener values, standards, practises and technologies – although it is yet to be seen whether this transformation is sufficiently rapid and comprehensive. Harich (Reference Harich2010) contends that sustainability science and practise have focused on coupling people with the environment, but the ultimate problem is resistance to change. Therefore, he argues that sustainability research should next focus on studying the dynamics of change, which is closely related to our interests in terms of understanding how transformative change can be captured.