The failure of the United Nations negotiations on climate change in Copenhagen presents governments with an opportunity to consider new approaches to implementing climate change policy. Developed nations like Canada and Australia continue to fall short of their commitments to Kyoto targets and predict that their greenhouse gas emissions will continue to rise. The planning and development of metropolitan areas continues to promote high levels of consumption and increased dependence on fossil fuel-based energy. City governments in Vancouver and Melbourne have strong commitments to both mitigation and adaptation policy action against the impact of global warming. Both argue they are constrained in their efforts by federal institutional arrangements and require improved cooperation from other levels of government. This article uses the conceptual framework developed by the OECD to support greater levels of cooperation between governments in multilevel systems when implementing climate change policies. The article examines the contextual factors inherent in the institutional arrangements and uses the experiences of Vancouver and Melbourne to explore the factors that encourage or discourage cooperation in climate change policy.