We face a planetary emergency made up of a compound environmental crisis, in which climate change is prominent but by no means the only element, and a darkening security horizon. Behind them, linking to both, lies a chronic problem in deficient mechanisms and instruments for addressing these environmental and security challenges.The planetary emergency is deepening as each year goes by, without any decisive action being taken to mitigate it. Communities across the world are already suffering the consequences of climate change and other forms of environmental deterioration, as well as of worsening insecurity, both separately and in combination. Thus, while this report spotlights a present danger, the problems of today may simply be the early stages of a growing global malady.The twin crises of the environment and security are linked in multiple ways. This has long been understood. There were even passing references to peace and security at the 1972 Stockholm Conference on the Human Environment-one in the declaration and a handful in debate. 1 In 1977, a Worldwatch Institute paper systematically linked the issues, including the challenge to peace and stability of a changing climate. 2 Among other efforts to move this discussion forward, a major article in 1989 concluded that environmental change was like the discovery of nuclear fission in that it would be a key determinant of security and policy in the decades ahead, and-as Einstein had said about nuclear weapons-necessitated 'a substantially new manner of thinking if mankind is to survive'. 3 In 1990 the journal of the traditionalist Royal United Services Institute in London carried an article exploring the conflict and security implications and consequences of climate change. 4 This report explores those linkages, some of which are subtle while others could hardly be clearer. An example of clear linkage is that 6 of the 10 largest United Nations peace operations and more than 80 per cent of UN peace operations personnel are deployed in countries recognized as being highly vulnerable to climate change. 5 If they do not take the impact of climate change into account, their work will be hampered and less likely