Résumé : It has become increasingly common to argue that climate change will lead to mass migrations. In this chapter, we examine the largenumbers often invoked to underline alarming climate migration narratives. We outline the methodological limitations to theirproduction. We argue for a greater diversity of knowledges about climate migration, rooted in qualitative and mixed methods. Wealso question the usefulness of numbers to progressive agendas for climate action. Large numbers are used for rhetorical effect tocreate fear of climate migration, but this approach backfires when they are used to justify security-oriented, anti-migrant agendas. Inaddition, quantification helps present migration as a management problem with decisions based on meeting quantitative targets,instead of prioritising peoples’ needs, rights, and freedoms.