The authors situate treadmill of destruction theory in a comparative international perspective to assess the environmental impacts of national militaries. Results of cross-national panel models indicate that high-tech militarization in the form of expenditures per soldier contribute to the scale and intensity of carbon dioxide emissions as well as the per capita ecological footprints of nations. Likewise, all three of these environmental outcomes are positively associated with military participation in the context of the number of soldiers relative to the size of domestic populations. Overall, the findings support the proposed theorization and highlight the need for social scientists to consider the environmental and ecological consequences of nations' militaries, regardless of whether or not they are engaged in conflicts.