Climate change poses significant challenges to urban areas, necessitating innovative solutions to enhance resilience and sustainability. This research explores the adoption of green roofs by housing associations in Amsterdam, a city highly vulnerable to climate change impacts such as flooding, extreme rainfall, droughts and extreme temperatures. Despite the recognized benefits of green roofs, their implementation remains limited. This study aims to identify the factors influencing housing associations' decisions to install green roofs and evaluate the effectiveness of current policy instruments in promoting this practice. While current policy instruments such as subsidies, Weerproof and coercion are in place, the adoption of green roofs has not been done by housing associations. The overarching research question is: “How do policy instruments for the promotion of green roofs influence the behaviour of housing associations in Amsterdam?”
The research focuses on the case study of housing associations in Amsterdam, combining desk research, interviews with policy officers and interviews with major housing associations. The Behaviour Change Wheel, incorporating the COM-B model and Theoretical Domains Framework, serves as the theoretical framework to analyse behavioural drivers and barriers. This comprehensive framework allows for a deeper understanding of the complexities surrounding the adoption of sustainable behaviours.
This research makes a contribution to the scientific literature through the use of the Behaviour Change Wheel (BCW) as a theoretical framework to analyse the adoption of green roofs by housing associations in Amsterdam. The BCW, typically applied within healthcare and behavioural sciences, is used in this study in a novel way within the context of urban sustainability and climate adaptation. By integrating the COM-B model and the Theoretical Domains Framework, this research provides in-depth insights into the behavioural drivers and barriers of housing associations. This methodological innovation broadens the applicability of the BCW and demonstrates its value for organizational behaviour change, specifically focused on sustainability and climate resilience.
Key findings indicate that while there is openness to the idea of green roofs among housing associations, significant barriers persist. These barriers include high installation costs, structural challenges, and a lack of knowledge about green roofs within housing associations. Current policies, such as subsidies and environmental guidelines, have not fully addressed these obstacles, particularly for existing buildings. For example, the subsidy availability has been inconsistent, which undermines the motivation for housing associations to commit to green roof projects. Additionally, while guidelines such as the “Nationale Dakenplan” have been established to promote green roofs, the lack of specific, targeted marketing and communication for housing associations limits their impact.
Reflective motivation is a primary barrier, with housing associations focusing on immediate and pressing needs like improving energy efficiency and addressing poor energy labels. This prioritization often leaves little room for green roofs, which are perceived as less critical. Financial constraints exacerbate this issue, as the high upfront costs of green roofs are often seen as prohibitive without sufficient subsidies or financial incentives. Moreover, housing associations often view the benefits of green roofs—such as increased biodiversity, urban heat island mitigation, and improved stormwater management—as less directly impactful on their primary goal of providing affordable housing.
The research highlights several intervention functions to overcome these barriers. These include enabling policies that integrate green roofs into energy label improvements, regional obligations for green roof implementation, targeted marketing campaigns, a stormwater runoff fee to create a business model for green roofs, and the promotion of comprehensive roof handbooks. Each of these interventions targets specific aspects of the COM-B model—capability, opportunity, and motivation—to encourage housing associations to incorporate green roofs more broadly.
By implementing these improvements, policy instruments can more effectively promote the adoption of green roofs, contributing to a more sustainable urban environment in Amsterdam. Further research should focus on validating these interventions in other cities to confirm their broader applicability. Additionally, evaluating the long-term impacts of these policies will provide insights into their effectiveness and inform future policy development.
Overall, the integration of comprehensive, targeted interventions can drive the widespread adoption of green roofs, enhancing urban resilience and sustainability in the face of climate change. This research provides a foundational understanding of the factors influencing green roof adoption and offers practical recommendations for policy enhancement to achieve a greener, more resilient urban landscape. 

Transdisciplinary (TD) research plays a crucial role in addressing the complex challenges of climate adaptation. Despite popularisation of TD research, ambiguity remains in the specific implementation of this approach. As more projects aim to adopt TD approaches, more clarity is needed to structure the organisation and implementation of TD projects. This study aims to provide insight from practice on how challenges and successes can be addressed in TD projects. Through an in-depth investigation of three TD projects, this research explores the key components of TD projects, identifies main challenges and successes, and elicits stakeholders' suggested improvements. The study consists of a comprehensive analysis of literature, expert interviews, interview data, and focus group discussions. A theoretical framework is developed to define TD concepts and relationships, addressing the issue of diffuse definitions. The research highlights the importance of shared understanding among stakeholders, particularly in addressing cultural challenges and achieving inclusiveness. Stakeholders' differing perspectives on successes and challenges are observed, leading to the identification of common themes across projects. The results underscore the significance of existing relationships and collaboration in TD projects, contributing to successful outcomes. However, certain challenges, such as inflexible institutional regulations, are also shared across cases. The analysis highlights the need for more explicit reflection on successes and structured approaches for envisioning improvements. The study also reveals a divide between participants based on their backgrounds, suggesting the importance of promoting knowledge integration among diverse stakeholders. Overall, this study contributes to the advancement of TD research in climate adaptation, empowering stakeholders to navigate complex challenges and foster sustainable solutions.