This dissertation examines the development of environmental cooperation in the South China Sea from the late 1970s when the first modest cooperative activities emerged among the small number of members of the Association of Southeast Asian Nations (ASEAN). Since the 1990s, the membership of the community has broadened and its efforts have become more focused and energetic. Through a study of the interactions among the three main actors engaged in regional seas cooperation, namely the United Nations Environment Programme (UNEP), ASEAN, and China, this dissertation seeks to explain the evolution of cooperation in the highly contentious South China Sea; the changing motivations, strategies and roles of the main actors; and the level of success with environmental politics in the region.

The study is driven by an intriguing puzzle. While the South China Sea remains one of the most volatile, dangerous and intractable areas, environmental cooperation has developed rapidly since 1990s. This is particularly puzzling when the geopolitical context, the large number of littoral states with a history of hostility among them, the domestic priorities these countries place on development, and their diplomatic preferences are taken into account. The key to the puzzle lies in UNEP's strategizing. UNEP utilized the United Nation's potential power of legitimization, independence and knowledge in areas that were not limited to the environment per se to induce cooperation among the littoral countries of this highly contentious region.

UNEP has played both inductive and instrumental roles in promoting environmental cooperation in the South China Sea. On the one hand, by framing environmental protection as a neutral, non-political and "low politics issue", UNEP has been able to draw the littoral countries to the negotiating table. This has internationalized environmental protection in the South China Sea, making non-participation in these cooperative efforts problematic since it could reduce the international prominence of a country's territorial claims. In this sense, UNEP has been able to induce cooperation. On the other hand, UNEP has played an instrumental role in promoting regional cooperation by helping countries to address common marine environmental problems and promoting confidence building measures between ASEAN countries and China.