This article addresses the broader question of the special issue by reflecting on the coloniality of knowledge production in a context of global climate governance. Drawing on the rationale of the special issue, we highlight key dynamics in which knowledge shape climate policies and propose a decolonial approach at the nexus of academic knowledge production and policy formation by accounting for diverse ways of knowing climate justice. To this end, the article asks how to develop a decolonial approach to researching climate justice in order to identify the meaning-in-use of climate justice by affected people in what we describe as sensitive regions of the Arctic and the Mediterranean. To this end, the article develops a research design that accounts for diverse ways of knowing. The article proceeds as follows: first, we will discuss how diverse ways of knowing are related to global climate governance and climate justice; second, we outline our practice-based research framework that addresses research ethics, decolonial approaches and norm contestation; and third, we discuss how our approach can inform not only the co-production of research in climate governance, but also current debates on climate justice.