The urgency for an ecological transition is consolidated today at international level. Earth Summits, CoPs and the institutionalization of environmental expertise bodies like the IPCC embody the imperative of environmental preservation. Yet, environmental global governance is often criticized as being weak, fragmented, and too or not enough ambitious. This course provides students with the necessary tools to analyze critically and head-on such negative conclusions. Has the legal weakness of Multilateral Environmental Treaties prevented States from making progress? Is fragmentation a shortcoming or an opportunity for environmental policy-making? Does the institutional architecture of Global Environmental Governance provide for a just transition?