The Russian War on Ukraine since February 2022 has caused multidimensional catastrophes in relation to human, economic, cultural, infrastructural, political, and environmental impacts. Of particular concern is the impact on Ukraine’s biodiversity, one of the most diverse in the European region, as well as the water resources within the borders of Ukraine. The main focus of this study is to analyze the ongoing ecological catastrophe caused by the Russian War on Ukraine, from the environmental security perspective. It examines the disparity between the environmental policies of the Russian Federation and the ongoing environmental destruction caused by the military invasion of Ukraine. Using the process tracing, content analysis and case study as methodological approaches, the study contributes to understanding the Russian War on Ukraine through a contemporary and analytical approach and reveals the inconsistent parts of Russian environmental policies. It also provides some broader insights into the role of environmental security during the war in the Anthropocene age.