Despite their seeming reluctance to engage in the politics of the now, historians have a crucial role to play as witnesses to climate change and its attendant social injustices. Climate change is a product of industrialization, but its effects are known in different geographical and temporal scales through the compilation and analysis of historical narratives. This essay explores modes of thinking about disasters and temporality, the Anthropocene, and the social production of risk – set against a case study of the Korean DMZ as a site for historical witnessing. Historical methods are crucial if we are to investigate deeply the social processes that have produced climate change. A “slow disaster in the Anthropocene” approach might show the way forward.