In the face of climate change, political and policy discussion is often framed by a concern with causal impacts on the societal status quo. Illustrated with the case study of the literature and debate on the relationship between climate change and migration, this paper argues that the search for causal understanding can be a blind alley for substantive research, and it is imperative for the research community to be aware of this possibility. To this end, the paper presents a tripartite heuristic framework, using the logic of an 'epidemiology', which allows such blind alleys to be identified, explained and collapsed. It goes on to then outline what remains for research in light of such a critique - in general, in terms of human geography and with specific regard to 'forced migration' scholarship and 'migration studies'. The core admonition is that potentially more is lost than gained when discussion and debate in both academic and policy contexts fails to begin by reflexively interrogating the specific forms of causal reasoning that are implicit in any attempt to substantively analyse the impact of climate change on any particular subjectively defined dependent societal variable, such as 'migration'. Failing to do so results not only in the waste of finite research resources, but also allows currency to accrue to otherwise equivocal constructs, thereby leaving them ripe for politically expedient manipulation.