For many practitioners and scholars of International Relations, security is the number one issue in global politics. The need to secure survival trumps all other imperatives where a ‘state of nature’ is said to prevail among nations. It seems appropriate, therefore, to begin our enquiry into the contribution of Green politics to global politics with this central concern. Despite the absolute centrality given to the politics of survival in orthodox representations of IR noted above, ecological questions are largely neglected. This is inspite of a now vast literature on environmental security and environmental conflicts. Here I explore Green critiques of militarism targeting the sources of violence and conflict, as well as the ecological impacts of war, before articulating visions of a Green security and considering strategies for achieving it through ecologising security, multilateralism and democratc defence.