Despite growing recognition of the importance of transdisciplinary research in addressing complex sustainability challenges, in practice it has been much hampered by persistent inequities, power disparities, and epistemological disconnect. Planetary health as an emerging field offers a unique lens highlighting the need for knowledge integration across the environment, health, and development (EHD) nexus. Drawing upon extensive analyses, including a meta-analysis of existing transdisciplinary frameworks, a literature review of practices in these fields, and a case study of a planetary health action research project in Indonesia and Fiji, we propose a framework to guide the design and implementation of transdisciplinary research.

The proposed framework was iteratively designed, starting with existing frameworks, complemented by findings and practice recommendations from a literature review of 36 publications of recent transdisciplinary practices in the EHD fields and an in-depth case study of a planetary health research from Indonesian perspectives. The practice framework focuses on the stakeholder collaboration process, and emphasizes reflexivity and co-learning throughout all research phases: initiation (co-design); implementation (adaptive co-management), and monitoring and refinement (co-monitoring). Foundational considerations for stakeholder engagement could inform process design by reflecting on stakeholder contributions, interactions, integration, and expected outcomes. As suggested by development studies, and implicitly agreed upon but insufficiently elaborated within environment and health, attention to the local context of the research, mapping of power dynamics, and the values of equity and inclusivity are pertinent if research is to produce credible, relevant, and legitimate knowledge and outcomes. A renewed focus on addressing power equities can help ensure stakeholders' perspectives and interests are equally valued and potential solutions are not inadvertently excluded as a legacy of systemic power imbalance. The practice framework is most effectively applied in the initial process co-design, by process initiators and funders assessing proposals for international transdisciplinary research in power-diverse settings or resource-poor contexts.

How can researchers across diverse fields collaborate with renewed focus on power inequities to accelerate progress towards the Sustainable Development Goals?