© 2018, Springer Japan KK, part of Springer Nature. In 2016, the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) published its first methodological assessment report on scenarios and models, identifying important gaps in the literature. IPBES has since then moved onto Phase 2, namely a commitment to build on the assessment findings to catalyse the development of the next generation of multi-scale models and scenarios for biodiversity and ecosystem services. Part of that commitment involves the inclusion of Indigenous and Local Knowledge (ILK) in those models and scenarios. IPBES is both an institution (with its governance structure, work programme, deliverables, and so on) and a network (with its member states, authors, stakeholders, and readership). Within that network, the methodological assessment report can be said to be ‘performative’, ergo playing a significant role in shaping engagement and research pathways in the years to come. Within the social sciences, this paper marks a first attempt at evaluating some of the potential challenges of Phase 2—with specific regard to the inclusion of ILK—and strives to generate more engagement from social scientists and humanities scholars on this issue. I combine in-depth expert interviews with document analysis and focus on the ideas of ‘scale translation’ and the translation of ILK into quantitative data—which I contend are likely to be the most contentious and arduous aspects of ‘integration’. I conclude that while IPBES is on track for leading the research community away from IPCC-type global, panoptic models and scenarios, a more honest and genuine dialogue between natural scientists, social scientists, and ILK holders is still required—so as to better communicate what may be (scientifically) feasible and (politically) acceptable.