The 2012 UN Conference on Sustainable Development Rio+20 generated a wide range of mostly negative reactions. Even before the conference, there was widespread doubt about the possibility of success. As soon as the conference closed, analysts highlighted its failures and criticized the outcome document, The Future We Want . While it does not present a grand transformative vision, the outcome document does reaffirm past political commitments and addresses the multiple dimensions of sustainable development and the linkages among them. Indeed, Rio+20 had subtle, yet significant impacts. Three main areas stand out: reform of international institutions, sustainable development goals, and participation as principle and practice. The global decisions in these domains and the unprecedented local engagement provide critical junctures likely to shape global environmental governance for the next two decades.

As debates on reform of global environmental governance intensify, the future of the United Nations Environment Programme (UNEP) has come into acute political focus. Many argue that the organization has faltered in its role as the UN's leading agency for the environment. In this article, I use historical institutional analysis in combination with current international relations and management theory to explain UNEP's creation and evolution. Having described how the creators of UNEP envisioned the nascent organization, I analyze its subsequent performance, identifying the key factors that have shaped its record. I argue that the original vision for UNEP was ambitious but fundamentally pragmatic, and that the organization's mixed performance over the years can be explained by analysis of three factors: its design, leadership, and location. Thus, this article clarifies the record on UNEP's intended function, and lays the foundation for a systematic methodology for evaluating international organizations.