Background: Real estate, infrastructure, and related urban systems are increasingly exposed to the physical impacts of climate change, threatening both their durability and societal stability. Today the understanding of urban climate risks and their management is emerging but incomplete, highlighting the need for collaborative, integrated, and transparent approaches. However, existing collaborative approaches do not often lead to practical and actionable solutions, exposing a gap in expertise on how to co-create truly integrative approaches in a landscape of fragmented knowledge. Method: This article introduces an integrated approach to transdisciplinary knowledge production on urban climate risk management, using the case of the Red&Blue programme (Real Estate Development and Building in Low Urban Environments). This research-intensive knowledge programme in the low-lying Dutch urban delta was co-created by diverse disciplinary researchers and cross-sectoral practitioners, including financial institutions. Here, the authors reflect on three key “how” questions concerning programme co-creation with stakeholders, the organization of the collaboration process, and capacity development for reflection on insights in transdisciplinary cooperation. Results: Preliminary findings over the last two-and-a-half years of the programme highlight key challenges in transdisciplinary cooperation. To address them, the authors stress the need for creating safe and open spaces for stakeholder dialogue, where diverse cooperation strategies help build shared vocabularies, enabling stakeholders to jointly define, identify, and analyze multidimensional climate risk issues and potential adaptation solutions. Conclusion: The integrated approach presented in this article offers a preliminary model and means to build integrated knowledge on climate risk management and related sustainability transitions in the built environment.

Despite growing government and market interest to use Circular Building Hubs for reusing construction components, few academic articles have been written about them. We know little about the potential of hubs to answer to the challenges of reuse in the present and future, and their potential to drive systemic changes towards a circular economy. Using various qualitative research methods, this article aims to respond to this research gap by applying social practice theory and the multilevel perspective on past and future practice reconfigurations within the system-of-practices in which these hubs reside. Results show that within hubs reconfiguration from demolition to deconstruction and repair and refurbishment practices have been developed. However, selling components remains challenging, and procurement for reuse and design skill remain underdeveloped. Practitioners expect the system-of-practices to professionalize in the coming years, resulting in market growth for secondary components. Long term, practitioners expect hubs to shrink or disappear because the balance between supply and demand will be controlled digitally. Hubs are therefore a driver for the transition, but only as intermediate step, not as solution for a circular economy. This article is particularly interesting for academics studying CE and transitions, and policy makers interested in developing Circular Building Hubs.

Purpose
The global housing shortage, intensified by climate change, poses unique challenges for low-income populations, particularly in regions highly vulnerable to environmental hazards, such as the Caribbean. This study investigates housing in Saint Martin, where communities face severe housing shortages and increased exposure to climate-related threats, such as Hurricane Irma in 2017. With limited external support, many residents have adopted self-building strategies, constructing and incrementally modifying their homes to withstand local environmental risks and accommodate changing needs.

Design/methodology/approach
This research, conducted through ethnographic observations and semi-structured interviews with 30 residents, explores how low- and middle-income households built and adapted their homes over time, focusing on the construction process, materials, forms and aspects of safety, comfort and beauty. It follows the narratives of six housing units that exemplify a proposed housing typology and documents residents’ efforts to enhance durability, functionality and aesthetics under challenging circumstances.

Findings
The findings highlight that self-organized housing practices in Saint Martin are shaped by financial constraints, climate risks and evolving household needs. Residents use incremental construction, climate-responsive design elements, materials perceived as durable and community-based support to adapt their homes.

Originality/value
Documented housing practices reflect both resilience and cultural expression, emphasizing the need for community-inclusive, safe, flexible and climate-adapted housing design approaches. Additionally, by analyzing these adaptive strategies, the study offers insights for the Designing for Flow Framework, promoting housing solutions that align with local contexts and contribute to sustainable development in hazard-prone areas like the Caribbean.

This article examines how bottom-up urban development initiators create social value through self-organization in a market-dominated context. Using a multiple case study and a framework combining collaborative governance and network uncertainty theories, we identify two key efforts: shaping initiatives through community building to establish trust, and aligning goals with state and market actors’ spatial-economic interests. State and market support is subsequently gained through goal-interest coupling, grounded in trust and facilitated by temporary use. Incremental self-organization thus involves adapting to market logic rather than opposing it, which contrasts with prevailing paradigms. This adaptation fosters social value but requires compromises from initiators.

This article aimed to assess the potential impact of policy actions to support mass timber construction through an ex ante policy analysis in Amsterdam. Through a combination of policy coherence analysis and agent-based simulation, the study evaluates 130 policy actions, including 80 specific instruments, for the transition from traditional masonry to mass timber construction. The coherence analysis reveals a predominance of regulatory instruments (62%) and a lack of active economic measures (16%), which limits their impact on circular city development. The simulation tested three instruments - demolition notification, a mass timber subsidy proxy and a carbon tax proxy - to assess their individual and combined effectiveness. Isolated measures, such as material price adjustments, were found to be insufficient due to systemic inertia. However, the combination of subsidies and carbon taxes proves more effective, significantly increasing the uptake of mass timber construction as its cost is reduced and construction companies develop expertise. A key finding highlights the complementary role of recycled concrete in supporting mass timber construction, highlighting the need for integrated policies targeting both mass timber and secondary materials. Improving industry knowledge and expertise is identified as a transformative approach to reducing costs and overcoming barriers to adoption. This research is the first contribution to demonstrate the value of ex ante policy evaluation and agent-based simulation in formulating coherent and effective policies for circular city transitions. Policy makers in Amsterdam and other Dutch cities are advised to implement synergistic instruments, support local material reuse and invest in capacity building to achieve carbon neutrality and resource circularity in urban construction. The findings provide actionable guidance for Amsterdam and similar cities seeking to promote sustainable and circular urban environments.

Increasingly, sustainability challenges in transdisciplinary courses are used to confront students with different dimensions of uncertainty, such as unpredictability, lack of knowledge, or ambiguity. However, little is known about how teachers adapt their teaching to scaffold students through such uncertainty. This design-based study investigates the adaptive guidance (scaffolding) employed by teachers to guide students through problem-solving in uncertainty. Using a sixteen-week challenge-based learning (CBL) course called the ‘Living Lab’ as a case study, we monitored how teachers developed scaffolding based on a workshop they received before the course began. Through qualitative questionnaires and focus groups conducted every four weeks, teachers reflected on their teaching practices and coaching strategies. The study identifies teaching problems faced by teachers in transdisciplinary courses, including theoretical grounding, tensions with the commissioner, and assignment clarity. Teachers most frequently used scaffolding for frustration control, marking critical features, and direction maintenance. Additionally, teachers lacked diagnostic strategies to assess student progress on personal learning objectives. This research contributes to a deeper understanding of the role of teachers as coaches in transdisciplinary courses. Practical implications include informing and inspiring teachers to enhance their scaffolding practices on diagnostics, theoretical grounding, and personal learning in CBL courses.

We see unprecedented weather causing widespread impacts across the world. In this perspective, we provide an overview of methods that help anticipate unprecedented weather hazards that can contribute to stop being surprised. We then discuss disaster management and climate adaptation practices, their gaps, and how the methods to anticipate unprecedented weather may help build resilience. We stimulate thinking about transformative adaptation as a foundation for long-term resilience to unprecedented weather, supported by incremental adaptation through upgrading existing infrastructure, and reactive adaptation through short-term early action and disaster response. Because in the end, we should take responsibility to build resilience rather than being surprised by unprecedented weather.

Energy-efficient renovation (EER) is a complex process essential for reducing emissions in the built environment. This research identifies homeowners as the main decision-makers, whereas intermediaries and social interactions between peers are highly influential in home renovations. It investigates information and communication barriers encountered during the initial phases of EERs. The study reviews AI tools developed within the EERs domain to assess their capabilities in overcoming these barriers and identifies areas needing improvement. This research examines stakeholders, barriers, and the AI tools in the literature for EERs. The discussion compares the functionalities of these tools against stakeholder needs and the challenges they face. Findings show that tools often overlook methodologies in human–computer interaction and the potential of textual and visual AI methods. Digital tool development also lacks insights from social science and user feedback, potentially limiting the practical impact of these innovations. This article contributes to the EERs literature by proposing an AI-supported framework and outlining potential research areas for future exploration, particularly improving tool effectiveness and stakeholder engagement to scale up the EER practice.

The architecture, engineering, and construction (AEC) sector is in need of a transition towards a circular economy. This article offers an analysis of two cases with a wide variation regarding project dynamics in the Netherlands. Alignments and misalignments were analyzed between practices concerning seven design strategies for circular design based on social practice theory and concepts from the multi-level perspective. Results show that many misalignments still hinder the transition, mostly concerning the use of secondary resources, such as notions regarding quality, beauty, and safety among project team members or rapid decision-making processes of the municipality that misalign with the uptake of design with secondary resources. This article offers directions for reconfiguration, such as better tuning between project planning and urban planning and taking up a more flexible stance regarding the function of the building. This research is interesting for practitioners and researchers focusing on the transition towards a circular economy in the AEC sector.

Circular economy (CE) is territorialised. Economic activities are spatially embedded; they operate across a variety of scales and are heavily influenced by their spatial context. Yet the CE academic literature and policy frameworks rarely address this dimension. If CE policies are to achieve sustainable development goals and be implementable at a subnational level, these shortcomings need to be addressed. In this chapter, we take stock of the current debates and policy on CE in cities and urban regions, critiquing them from a spatial, socio-ecological and governance perspective. On that basis, we outline a new policy and research agenda to bridge the above-mentioned gap and inform the development and implementation of place-based CE policies.

As circular economy policies are adopted to tackle unsustainable built environment patterns related to carbon emissions and inefficient use of resources, scholars warn about the inadequacy of such policies to support sustainable urban development. Siloed circular economy policies in the built environment have focused on applying circular strategies to construction practices. However, cities as complex adaptive systems require systemic interventions including ecologically regenerative and adaptation actions to bring about a more circular built environment and, ultimately, a circular city. This article analyses policy coherence –or the (mis)alignment and possible synergies– of circular built environment in Greater London. Resorting to a circular city policy coherence framework, through document analysis of planning and circular economy policies and semi-structured interviews, both the state of circular built environment policy is assessed and policy recommendations are provided. Circular built environment policies in Greater London have increased in their overall coherence by means of the application of circular economy principles in construction practices, but less so in bringing about a circular city. The findings contained herein may inform policy making in Greater London and other cities of the world to help improve their circular city policy responses to the complex societal challenges imposed by the ongoing socio-ecological crisis.

Although gentrification and its associated changes in residential mobility have been widely studied, surprisingly little attention has been paid to the changing origin locations of gentrification-related residential moves. In this study, we use fine-grained register data from the Dutch Central Bureau of Statistics to uncover changing residential mobility patterns to and within the city of Rotterdam, the Netherlands. We identify that the state-led gentrification process goes hand in hand with the changing socioeconomic characteristics of in-movers and the changing origin locations of residential moves. The city of Rotterdam increasingly attracts middle- to high-income households from other core cities in the Netherlands, a process that we understand as inter-urban gentrification spillover. In parallel, intra-urban moves by economically vulnerable residents are declining, especially toward and within gentrifying neighborhoods. This represents evidence of exclusionary displacement. We conclude that the spillover effects of contemporary gentrification should be understood beyond an intra-urban metropolitan perspective since gentrification in one city can enhance gentrification in another.

The urgency of addressing housing challenges in low-income areas is increasing due to widening socio-economic inequalities and the worsening impact of natural disasters. Saint Martin, a small Caribbean island, is struggling to provide affordable housing amidst hurricanes, floods, and heat waves. As a result, there has been a rise in self-organized housing units, which are built incrementally and are susceptible to risks. The main challenge is to balance durability, functionality, and esthetic appeal over time. Inspired by St. Martin’s self-organized units, this article explores housing considerations in low-income, hazard-prone contexts by emphasizing their temporalities. Integrating insights from a formative study, including a literature review and ethnographic research, the paper draws on Stewart Brand’s “Layers of Change” and the concept of “Flow”. The study identifies layers within self-organized units corresponding to durability, functionality, and esthetic appeal. It delves into their connection with building activities over time, unveiling the temporalities of housing considerations. This exploration leads to the proposition of “Designing for a Flow” as a novel design approach. Offering practical insights within a concise framework, the study provides nuanced perspectives on mitigating housing challenges in low-income and hazard-prone contexts.

While tackling sustainability challenges, engineering students confront various uncertainties, including the unpredictability of real-world scenarios, unfamiliar aspects of problems, and conflicting viewpoints among stakeholders. Despite previous research indicating the likelihood of encountering such uncertainties in sustainability projects, it is unclear if students are aware of uncertainty and what specific regulatory behaviors they develop to address them. This study seeks to deepen our understanding of the awareness and regulation of uncertainty by students while they work on real-life sustainability challenges. To achieve this, we observed nine MSc students enrolled in a transdisciplinary course on urban sustainability at a Dutch university of technology. Through interviews, we explored the uncertainties they faced and how they navigated them. Our analysis, conducted through open, consensus-based coding by two researchers, revealed that students primarily encountered the uncertainty of multiplicity, characterized by divergent stakeholder perspectives. Additionally, students increasingly recognized the inherent unpredictability of the challenges over the course. To address uncertainty, students developed three kinds of behaviors to deal with uncertainty: seeking social support from commissioners, coaches, and peers; employing small coping mechanisms to overcome obstacles; and developing attitudes such as empathy, flexibility, and relativism. This study offers detailed insights into how students navigate uncertainty. Moving forward, efforts in uncertainty education should prioritize how educators can positively influence the development of metacognition in uncertainty.

Increasing resilience to flooding is a complex process that requires horizontal and vertical coordination between institutions in policy making and implementation. This paper explores the effect of institutional coordination on managing flood risk in two cities plagued by flooding. Our results show that efforts on building urban flood resilience can be undermined by lack of proper coordination between urban development, water management and land use planning. We find that this complexity is magnified by the emergence of the concept of resilience as an urban development goal that is increasingly pursued by various authorities, but that is inherently contested in practice.

Researchers employ many different approaches to study transitions towards more sustainable futures, of which Sustainability Transitions Research and Social Practice Theory are often used. These approaches offer complementary concepts that are helpful to analyse, explain, forecast, and drive sustainability transitions, e.g. heuristics on changing institutions (Sustainability Transitions Research) or dynamics to change behaviour through practice development (Social Practice Theory). However, despite first attempts, it remains unclear how the approaches can be used together. Therefore, the aim of this paper is to expose crossover frameworks in which these approaches are used together, elaborating on conditions that make this possible, and the strengths and weaknesses of specific crossover frameworks. A systematic literature review has been conducted, investigating the potentials and the limitations for crossovers between Social Practice Theory and Sustainability Transitions Research by analysing the approaches according to the different ontologies and theories and then analysing frameworks that have been created so far. This research elaborates on six crossover frameworks that have been created that all have diverse strengths, such as the ability to conceptualize early transitional changes or finding points of resistance in transitions. All the found crossover frameworks made use of either the multilevel perspective or transition management. Other frameworks of transition research have not been found. This research shows that there has been surprisingly little research to crossover frameworks that incorporate an element of time. The exposition following from this study is interesting for researchers and policymakers working on sustainability transitions and sets an agenda for further framework development.

This closing chapter brings together the main messages from each chapter. It formulates a policy agenda for circular cities and regions. It does so by providing a set of recommendations for policy practice. These are addressed at authorities and policy stakeholders at the international, national and subnational levels.

Klimaatverandering zorgt tal van nieuwe risico’s voor gebouwen en infrastructuur. Het in kaart brengen van deze klimaatrisico’s is in volle gang, maar de betrouwbaarheid van de beoordelingen die hieruit volgen laat te wensen over en dit maakt de handelingsbasis beperkt. Dat concludeerden de experts die deelnamen aan de eerste Focal Point Meeting van het Red&Blue-programma over klimaatadaptatie.

Gentrification is a process whereby neighbourhoods and their socio-economic composition upgrade through residential moves and social mobility. Relatively little attention has been paid to the spatial aspect of gentrification-induced residential moves. This systematic literature review focuses on the origin and destination of moves to and from gentrifying neighbourhoods, by gentrifiers (movers in) and displacees (movers out). It identifies where, when, and how such research has been conducted and highlights gaps in the literature. Our results suggest that the destination of displaced households has been studied extensively, while an understanding of the spatial origins of gentrifiers is lacking. The few studies dedicated to gentrifiers' origins mostly focus on intra-urban environments, overlooking potential mobility dynamics from outside the city-region. We highlight that capturing both origins and destinations of movers at different spatial scales is necessary to demonstrate how residential mobility creates interactions and demographic interdependencies between neighbourhoods and cities.