Can environmental problems lead to security problems? Answers to this question require an understanding of what constitutes security. Security for whom? States? Individuals? This course will primarily review two waves of scholarship on environmental security, the first from the 1990s in which scholars assessed the connections between environmental problems and conflict, and the second from the 2000s on the connections between climate change and security. In the process, the course will review different conceptions of security, from narrow conceptions that focus on environmental change and conflict onset to broader understandings of human security. We will also familiarize ourselves with the nascent practice of climate security initiatives, including what militaries are doing to respond to climate change, climate security at the UN and other multilateral organizations, and the challenges of environmental peacebuilding. Along the way, other side discussions of environmental security will be explored including (1) wildlife poaching crisis and security, (2) environmental peacemaking (3) the effects of war on the environment and (4) the geopolitics of the clean energy transition.