This chapter focuses on the environmental diplomacy surrounding the World Commission on Environment and Development, popularly known as the “Brundtland Commission.” This process popularized the concept of sustainable development. The chapter begins by detailing the substantial changes seen in international environmental conditions through the mid-1980s, brought about largely by the Third World Debt crisis. These shifts created a rapidly deteriorating global environmental context and necessitated significant changes in institutional arrangements. The need for institutional change was a central finding of the important 1987 “Brundtland report,” titled Our Common Future. The Brundtland Commission highlighted a rapid deterioration in the world environment and underlined the need for major institutional change. Some actors sought to realize such change at the United Nations General Assembly in 1987, when the report and its call for action were presented to world leaders. Coordination was hindered, however, by divergent expectations and the absence of a Temporal Focal Point. While states were incentivized to cooperate rapidly to address problems in global environmental governance, the institutional status quo prevailed.