In 1988, nuclear war was “undoubtedly the gravest” threat facing the environment, according to Our Common Future, commonly known as the Brundtland report. New analytical developments are bolstering policymakers’ and practitioners’ interest in practical ways to break the links between environment and conflict. The reaction to the September 11 attacks certainly set back efforts to address environment and security linkages. The heightened attention to climate change boosts the prospects for constructively addressing environment, development, and security linkages. The cooperation imperative spurred by environmental interdependence and the long-term need for iterated interaction can be used as the basis for confidence building rather than merely engendering conflict. Environmental peacemaking efforts have limited use for unwieldy multilateral environmental agreements, the United Nation’s go-to tool, which are poorly matched to the day-to-day intersections of environment, peace, and security issues at the intrastate level.