Northeast Asia (NEA) is characterized by the absence of a comprehensive regional institution comparable to that of the European Union (EU), the Association of Southeast Asian Nations (ASEAN), and the South Asian Association for Regional Cooperation. Despite the prevalence of common challenges to the peace and security of the region during the cold-war era, political rivalries, historical animosities, economic disparities, and diverging systems among the countries in the region have acted as obstacles to the formation of a centralized coordinating mechanism that would address such challenges. This in turn has produced a spillover effect to regional environmentalism, where interstate cooperation has mainly remained insignificant with the exception of certain bilateral arrangements.