The Intergovernmental Panel on Climate Change (IPCC) has been criticized for having a limited impact on policy decisions and actions. To enhance the IPCC’s impact, it has been argued that the organization needs to adopt a more inclusive assessment process. However, what that means in terms of institutional changes is contested. Two main strands are discernible in the literature: studies advocating for moderate versus radical changes. In light of these two possible pathways, this study analyzes how the new role of Chapter Scientist shapes the conditions for socialization and what implications this may have for the future direction of the IPCC’s deliberative capacity. By identifying the norms and logic that guide inclusion in the role of Chapter Scientists, the study sheds light on which path the organization is moving. The study shows how the IPCC sustains a moderate path of inclusion and deliberation, as well as illustrates how the introduction of the role of Chapter Scientists could open up the organization to more radical institutional changes, which some view as essential.