The European Union’s circular economy (CE) policy aims to foster closed-loop systems that reduce waste and resource use, yet its practical implementation remains limited. Open innovation (OI)—the cross-organizational sharing of knowledge and collaborative problem-solving—offers a promising but underexplored pathway to accelerate circular economy transformation, particularly by enabling collaboration among diverse actors. This study addresses a critical research gap by examining how OI instruments mobilize multi-actor collaboration for circular economy goals, using an in-depth case study of Fab City Hamburg (FCH)—a pioneering initiative combining OI and CE principles to promote local, open, and circular production. Drawing on qualitative analysis of two circular open labs within FCH and integrating insights from transition theory with the small wins governance framework, we offer original insights into the dynamics of open innovation for circular economy transformation. Our findings reveal that open innovation instruments foster spreading and partial deepening of circular practices by supporting learning, experimentation, and community-building. However, significant barriers to broadening collaborations persist, including conflicting understandings of openness and circularity, organizational asymmetries, and unstable funding structures. The study contributes to the literature on CE and OI by offering a multi-actor, governance-oriented perspective on collaborative circular innovation. We highlight both synergies and frictions in applying OI to CE contexts and provide practical guidance for policymakers, intermediaries, and practitioners seeking to foster collaborative innovation and overcome barriers in circular economy transitions.

In recent years, weather-related extreme events have shown the limits of technical approaches to urban water challenges and highlighted the urgent need to rethink the relationship between cities and water and to see water as a partner in shaping transformative, climate-safe and just urban futures. However, existing scientific studies depicting future trajectories of urban water management have struggled to make the intertwined social and ecological dynamics of (transformative) urban adaptation tangible and accessible. This study focuses on the potential of visual communication of scenarios to stimulate both learning among scientists (during the process of creating the scenarios) and social learning (as a next step using the developed “narrative images”) to motivate diverse societal actors to engage with the complexity of sustainable urban water management. Art can overcome barriers of scientific and technical concepts and touch peoples' inner motivation for preserving and sustainably transforming our cities in a way that written texts cannot. As sustainability challenges transcend disciplines, this study draws methodically on an interdisciplinary scenario approach. Three adaptation scenarios were developed in a participatory process and professionally visualized as “narrative images” using the city of Hamburg as a case study. The scenarios take place in 2050 depicting a gradient ranging from coping to incremental adaptation to transformative adaptation for managing the water-adaptation nexus: “Water defensive city,” “Water resilient city,” and “Water aware city.” The scenario study shows innovatively how to bring the humanities, natural and engineering sciences into a deliberative dialog, while at the same time promoting collective learning. It can serve as a model for successful future interdisciplinary research and scenario developing exercises.

Climatic and ecological changes across the globe represent a challenge for humanity that can only be solved through a great transformation, that is, a widespread shift toward sustainable spatial development. This means addressing transformation needs in all systems to recognize that civil society, economies and politics are all predetermined by planetary boundaries. This transformation demands that the fields of applied spatial science and spatial planning identify strategies and solutions. This paper examines the extent to which these topics are already being addressed by the university- level spatial studies programs currently training future plan develops and examines criteria for evaluating these programs using guideline-based interviews and literature research to perform detailed analysis of selected programs. The study demonstrates that not only specialist knowledge, but also personal and methodological skills are crucial to the success for far-reaching change processes and, ultimately, a society- wide paradigm shift. In some cases, these skills are already being addressed by individual spatial studies programs, especially planning programs. However, there remains a need to accelerate the cultivation of independent learning skills and collaboration in inter- and transdisciplinary teams. Accordingly, this paper proposes a differentiated view of teaching and learning formats in higher education and encourages deepening the focus of spatial studies programs on sustainability and transformation issues.

Urban planning and public health are main fields of action when looking at urban development from a health perspective. In both fields of action, politics and administration as well as urban initiatives play a formative role. Action is oriented towards common overarching themes of sustainability, social justice and environmental justice. These commonalities are reflected in different memoranda. Despite the common basis of urban planning and health, there are areas of tension that are rooted, among other things, in different legal frameworks and logic of action. Against this complex background, recommendations are formulated for science, the funding landscape, practice as well as education and training in these areas.

City-regional discourses around organisational forms offer little evidence to analyse and guide cooperative processes in a context-specific way. Design criteria can contribute to overcoming this deficit. This paper operationalises a proposed set of design criteria by drawing on the discourses on collaborative governance and land management. Subsequently, these design criteria are used to analyse an ongoing process for the development of a housing development concept in the Leipzig city region and to reflect on the criteria. This contributes to the question of how collaborative governance of land-use development in city regions should be designed. Important points of reference for the design of cooperations are the conscious selection of the actors to be involved and the development of mutual trust between them, joint definition of rules of the game for cooperation, determination of the nature of the emerging institution, orientation of the joint work towards the future and the development of a common understanding of the situation to be improved.

Governance of climate mitigation and adaptation has been discussed within polycentric and multi-level governance perspectives. Both perspectives on climate governance are intimately related but yet in some regards are distinctly different - as one perspective has evolved from empirical research within the United States and the other in the European Union. Within an increasingly global discourse on climate governance, there is a need in the literature to bring both discourses together. The findings are based on a systematic literature review of 42 climate governance papers published since 2000. This paper discusses how multi-level and polycentric climate governance perspectives converge and diverge along five dimensions. The five dimensions provide insights for applying a multi-level or polycentric governance perspective to empirical research.

To reduce CO2 emissions to a sufficient extent, transformations are needed that have an impact and inspire people to imagine different futures. Real-life experiments (e. g., temporary car-free zones) are seen as a suitable instrument to induce transformation and to contribute to the mobility transition. Through a literature review on transformative research and the empirical case analysis of two temporary car-free zones in Hamburg, Germany, the transformative effect of real-life experiments was investigated. In this article, the history and evolution of experimental practice in urban spaces is described and four types of car-free zones are introduced. The analysis demonstrates that real-life experiments are drivers of transformation. A newly developed ideal-typical process, consisting of eight steps for initiating and planning temporary car-free zones is presented. It is aimed at helping practitioners design such zones to optimize their transformational power for sustainable urban development.

This article explores the enabling factors and actors involved in the transformation pathways towards climate resilience of two German cities: Halle (Saale) and Mannheim. A specifically developed analytical framework served as basis for making the complex developments of the transformation paths of the two cities visible and comparable. The analysis has shown that despite strong similarities in terms of climate change impacts, the cities acted under very different political and economic conditions and thus applied particular strategic and tactical approaches and steering instruments. It can be stated that preparation of climate strategies, creation of a supporting central unit for climate issues and exemplary implementation of selected measures by the administration, as well as awareness-raising and cooperation with the stakeholders and citizens have played a key role in the cities' transformation. In both cities, the city administration took the role of innovation organiser and orchestrated the path-way towards becoming climate resilient.

Many metropolitan regions face concerns over sprawling development, increased costs of maintaining infrastructure, and loss of green space and farmland. Some metropolitan regions have intentionally created spatial policies to govern development patterns and manage growth within their region. This paper compares the spatial policies applied in three case studies: the Puget Sound region (Washington State, USA), Metro Vancouver region (British Columbia, Canada) and Stuttgart region (Baden-Württemberg, Germany). While all three regions share a vision that can broadly be summarised as transit-connected communities, each metropolitan planning organisation leverages a variety of spatial policies. Based on the unique planning cultures, various governmental actors take on different roles at the local, county, regional and state levels. This paper categorises and compares the multi-level responsibilities for defining, mapping, and implementing spatial policies. With this focus, the paper provides an international comparative perspective on approaches, context, and contents of multi-level growth management.

Cities are essential players in responding to the present complex environmental and social challenges, such as climate change. The nature-based solution (NbS) concept is identified in the scientific discourse and further recognized by the European Commission as a part of the solution to address such challenges. Deploying NbS in urban contexts requires the cooperation of different public and private stakeholders to manage those processes. In this paper, the experiences of establishing and managing NbS-related processes following a co-creation approach in the city of Hamburg within the framework of an EU-funded research project (CLEVER Cities) are described and analyzed. The paper identifies and discusses the main emerging factors and challenges from (1) a procedural and methodological perspective and (2) concerning the different roles of the diverse stakeholders involved. This discussion is grounded in the context of existing regulations and novel concepts for citizens’ participation in urban decision-making processes. As research results, the article defines the leading players involved in the process and their roles and interrelationships, along with recommendations for future policy agendas in cities when dealing with NbS planning.

Rising average temperatures and more frequent occurrence of heat islands increase the vulnerability of urban society in Halle (Saale) and Mannheim. Dealing with the associated challenges requires not only locally adapted strategies, but in particular an interdepartmental approach and involvement of those affected. Living labs in both cities open up the possibility of testing this in a transformative process. This paper discusses the challenges that living labs are confronted with in terms of knowledge already in the finding phase and what needs to be taken into account to support this process in the best possible way.

The article argues that to reach circular economy goals urban regions need to identify and understand the challenges and opportunities originating from the differences in spatial settings, and to develop place-based solutions by adequately involving (local) stakeholders. Based on the case study that was conducted in Hamburg within the Horizon2020 project REPAiR, spatial specificities in five different urban areas shall be analysed and strategies that were developed in a co-creative process shall be explored. The results show that the spatial organisation of CE strategies depends on urban structures and stakeholders’ interest and needs to be embedded in the (local) governance setting and a spatial planning system.

This paper identifies and explores key elements for planning and implementing citizen involvement in the area of waste management and circular economy in cities. The analysis has shown that institutions responsible for waste management regard strategic planning, inclusivity, transparency, continuity, and resources as particularly important for reaching the objectives of citizen involvement. However, not all of the four analysed cities have applied these elements to the same extent, due to e.g. a lack of a strategy for citizen involvement, or limited personal and financial resources.

Energy-efficiency improvement measures for existing building stock are vital for reaching EU climate mitigation and energy targets, especially in urban areas, which are responsible for a large share of total energy consumption and CO2 emissions. The complex and multi-faceted nature of the energy sector is characterized currently by fragmented planning practices and a lack of cross-sector action to improve resource efficiency. The authors examine a comprehensive multi-stakeholder collaboration model at the district-level as a method to systematically address challenges of energy planning in urban areas while exploiting synergies with local conditions. A detailed description and evaluation of formats for successful collaboration is provided, considering lessons learned by the Interreg BSR project AREA 21 including seven cities from the Baltic Sea Region (BSR). The authors propose five main features for stakeholder collaboration in energy planning: inclusivity, intermediate scale, interactivity, mutual benefit, and institutionalization. The analysis provides evidence of successful multi-stakeholder collaboration that resulted in the development of strategies and action plans for energy improvements for the selected urban areas.

Diverse concepts have emerged in recent decades which (at least in their rhetoric) aim to instigate processes that make cities more resilient to climate change and support more sustainable urban development (Coaffee and Lee 2016; Hodson and Marvin 2017). With regards to urban water management, the Water-Sensitive City (WSC) is one such concept that promotes urban water planning to “protect, maintain and enhance the multiple benefits and services of the total urban water cycle that are highly valued by society” (Wong and Brown 2009, 674). The WSC, along with related integrated urban water management concepts have seen growing scholarly attention in recent years (see e.g. Fletcher et al. 2015). The emergence of such concepts reflects the growing demand for more sophisticated and integrated understanding and management of urban water systems. Such an ambitious model represents a broadening of the competencies and responsibilities of practitioners involved in water management and improved coordination with other urban sectors. Thus, such changes (must) typically coincide with changes amongst actors engaged directly or indirectly in water management, along with the prevailing institutional arrangements that govern their activities. Yet very little is known about processes of institutionalisation of such concepts within socio-technical regimes such as those that characterise urban water systems (Fuenfschilling and Truffer 2014). This paper aims to map processes of institutionalisation of concepts associated with the Water-Sensitive City amongst practitioners working in urban water management related fields in the Free and Hanseatic City of Hamburg. The research explores changes in the institutional arrangements between 1990 and 2020. References Coaffee, J., and P. Lee. 2016. Urban Resilience: Planning for Risk, Crisis and Uncertainty. Macmillan International Higher Education. Fletcher, T. D., W. Shuster, W. F. Hunt, R. Ashley, D. Butler, S. Arthur, S. Trowsdale, et al. 2015. ‘SUDS, LID, BMPs, WSUD and More – The Evolution and Application of Terminology Surrounding Urban Drainage’. Urban Water Journal 12 (7): 525–42. https://doi.org/10.1080/1573062X.2014.916314. Fuenfschilling, L., and B. Truffer. 2014. ‘The Structuration of Socio-Technical Regimes - Conceptual Foundations from Institutional Theory’. Research Policy 43 (4): 772–91. https://doi.org/10.1016/j.respol.2013.10.010. Hodson, M., and S. Marvin. 2017. ‘Intensifying or Transforming Sustainable Cities? Fragmented Logics of Urban Environmentalism’. Local Environment 22 (sup1): 8–22. https://doi.org/10.1080/13549839.2017.1306498. Wong, T. H. F., and R. R. Brown. 2009. ‘The Water Sensitive City: Principles for Practice’. Water Science and Technology 60 (3): 673–82. https://doi.org/10.2166/wst.2009.436.

The concept of the smart city has become increasingly popular in recent years and a large number of cities globally follow smart city strategies. By awarding subsidies in the Horizon 2020 programme, the European Union (EU) has taken on an influential role in how smart city projects are conceived and implemented in European municipalities. Using the example of the smart city pilot project mySMARTLife in Hamburg, the purpose of this article is to examine the area of tension between strategically pursuing own objectives and adjustment to external provisions of the EU funding framework. In a qualitative single case study, the article analyses what implications the project mySMARTLife has on urban development practice and local governance arrangements in Hamburg. Examining current literature on smart cities from the perspective of multi-level governance and presenting the current state of research dealing with EU smart city projects, a theoretical framework is developed. The analysis reveals that, due to the EU funding framework, precise project contents are contractually defined at an early stage when local stakeholders have limited involvement in this process. Furthermore, the analysis shows that the EU smart city funding in the project mySMARTLife is more limited to the implementation of individual interventions than to a comprehensive smart city strategy. As a result, this article considers EU-funded smart city initiatives as experimental fields that enable cities to gain experiences that can be incorporated into local strategic development objectives.

Urban areas account for around 50% of global solid waste generation. In the last decade, the European Union has supported numerous initiatives aiming at reducing waste generation by promoting shifts towards Circular Economy (CE) approaches. Governing this process has become imperative. This article focuses on the results of a governance analysis of six urban regions in Europe involved in the Horizon 2020 project REPAiR. By means of semi-structured interviews, document analysis and workshops with local stakeholders, for each urban area a list of governance challenges which hinder the necessary shift to circularity was drafted. In order to compare the six cases, the various challenges have been categorized using the PESTEL-O method. Results highlight a significant variation in policy contexts and the need for these to evolve by adapting stakeholders' and policy-makers' engagement and diffusing knowledge on CE. Common challenges among the six regions include a lack of an integrated guiding framework (both political and legal), limited awareness among citizens, and technological barriers. All these elements call for a multi-faceted governance approach able to embrace the complexity of the process and comprehensively address the various challenges to completing the shift towards circularity in cities.

Urban-rural partnerships are project-oriented cooperation initiatives between different actors in metropolitan areas and their surrounding or more distant rural hinterlands, the aim being to establish stable but flexible cooperation structures. As such, partnerships can contribute to different goals of European spatial development: (a) they can support polycentric spatial development and create incentives for further urban-rural relationships (cf. CEC in ESDP European spatial development perspective, 1999, 20), (b) they recognize the mutual urban-rural dependency by integrated planning and steering based on a broad partnership approach, and (c) they link to the concept that metropolitan regions and their hinterland should build partnerships of joint responsibility for development of the cooperation area (CEC in Territorial Agenda of the European Union 2020 2011, 8). The chapter reflects upon the concept of urban-rural partnerships in Peri-Urban areas and its potential to contribute to regenerative transformation of cities and regions using selected case studies from the project INTERREG IV C URMA "Urban Rural Partnerships in Metropolitan Areas" (2012-2014). In addition, it addresses the findings of the INTERREG IVB SURF "Sustainable Urban Fringes" (2009-2012). Finally, the chapter explores potentials and restrictions of different forms of urban-rural cooperation with regard to regenerative regional development.

"Jörg Knieling — From Sustainability to “Great Transformation”: Reflections on Klaus Kunzmann’s Thoughts about Planning Education in Europe." disP - The Planning Review, 53(2), pp. 72–73

In Germany, sustainability developed into a guiding, normative concept for spatial planning and spatial development following the Brundlandt Report 1987 and the Earth Summit in 1992. Since the idea of societal transformation suggests fundamental changes in social relationships and practices, this also includes questioning spatial planning practices and the roles of urban planners in the context of urban development. Planning practitioners can thus influence sustain-ability transitions at niche or regime levels and contribute to sustainable spatial development in a variety of processes and ways. In particular, planners with innovative, rather than business-as-usual, approaches, concepts, and views have the potential to become such pioneers. Planning pioneers emphasise the need for constant learning in view of real-life problems and for developing new methods to deal practically with the challenges of sustainable development. Flexibility and the experimental use of new techniques of communication and cooperation are recurring characteristics of the instruments and methods of the innovative planning practitioners.