This presentation studies the ways in which the Korean War impacted the environment. It is particularly concerned with environmental disasters associated with warfare. Historian J. R. McNeill has characterized the 1950s as the onset of the “Great Acceleration,” which denotes the intensification of environmental degradation during the Cold War. Environmental histories on Korea’s experience of the Cold War have usually focused on the consequences of industrialization, urbanization, and developmental economies after the Korean War. This project shifts the focus from the postwar economic development to warfare itself and study the immediate effects of the war on the environment. In doing so, it offers historical clarity to the understanding of the early phase of the Great Acceleration and revisit the importance of the Korean War in environmental history. The research examines some of the key moments of wartime catastrophes. Firstly, the destruction of cities, villages, and infrastructures across Korea entailed massive reconstruction works that not only lasted for decades, but had profound impact on the natural environment. Furthermore, the war displaced millions of civilians, whose concentration in urban areas resulted in the shortage of resources, increased pollution, famine, and the spread of diseases. The military conflict also led to deforestation and chemical contamination. The highlight of the research concerns the bombing of various water dams during the Korean War and the effects of the flood and famine that ensued. This research concludes by reflecting on the role that military activities play in demolishing and reshaping the environment.