The objective of this article is to examine how international relations (IR) theory has been understood and used to analyze environmental problems and in turn how environmental studies have contributed to the development of IR theory.<br>In order to trace the interrelationship between the two, this article analyzes international politics about global climate change.<br>The main IR theories, which are introduced in this article, include the dyads realism/neorealism, liberalism/neoliberalism (or institutionalism), and constructivism/cognitivism.<br>Among them the institutionalist perspective is the most useful one for the analysis of international environmental politics.<br>However, the realist perspective, which emphasizes relative gains between states, has certain explanatory power especially to explain why international negotiations on climate change regime often result in gridlock.<br>Furthermore, scientific knowledge plays a significant role in identifying complex problems such as climate change and biological diversity so that ideas and knowledge are crucial factors to explain international environmental politics.<br>Two UN conferences on the environment held in 1972 and 1992 helped promote studies on international environmental politics and the main academic debates in international relations have revolved around international cooperation.<br>Against this backdrop, international regime studies became an academic fad in the 1980s and 90s.<br>Above all, international environmental studies led this field of research by generating numerous studies on regime formation and development, some of which attach great importance to the role of idea and knowledge, or more precisely to the role of an “epistemic community,” a transnational community of scientists and experts.<br>In the course of the advance of studies in international environmental politics, along with the development of various international regimes consisting of multilateral environmental agreements (MEAs), new research foci have emerged such as study of the effectiveness of regimes, regime interplay (or regime complex), and global environmental governance and the role and influence of non-state actors.<br>The debates about climate change address all of the major issues discussed within academic communities, diplomatic communities, business and industry as well as NGO communities.<br>Specifically regarding the international politics of climate change, this article takes a closer look at the issues that constitute the edifice of IR studies: that is, the relationship between science and politics, regime effectiveness and power politics, the role of sub-state and non-state actors, as well as regime interlinkage and multi-stakeholders.