Bridging the accountability gap: designing a China-Japan-Korea judicial cooperation framework for transboundary marine plastic pollution

Marine plastic pollution in Northeast Asian seas exhibits significant transboundary characteristics, yet existing governance regimes—particularly the Northwest Pacific Action Plan (NOWPAP)—lack judicial enforcement mechanisms to hold polluters accountable. The diffuse nature of pollution renders traditional tort law’s causation requirements inoperative. Objective: This study constructs a trilateral judicial cooperation framework among China, Japan, and Korea to address the accountability vacuum in transboundary marine plastic pollution cases. Employing comparative legal analysis of international environmental tort precedents ( Trail Smelter , Pulp Mills cases) and institutional design methodology, this research adapts the U.S. market-share liability doctrine to transboundary pollution contexts and proposes a three-tier cooperation mechanism. The proposed framework comprises: (1) evidence collection and sharing protocols utilizing chemical fingerprinting and oceanographic drift modeling; (2) jurisdictional coordination rules to prevent forum shopping and parallel litigation; and (3) mutual recognition and enforcement mechanisms for environmental judgments. The framework leverages the existing Tripartite Environment Ministers Meeting (TEMM) platform while transforming it into an enforceable judicial architecture. By reconstructing causation requirements through pollution contribution ratios and establishing systematic judicial cooperation, this framework provides a replicable model for regional ocean governance. It directly contributes to ongoing International Plastics Treaty (INC) negotiations on transboundary liability provisions and demonstrates how soft law regimes can evolve into hard enforcement mechanisms. Yet the framework’s practical realization ultimately depends on participating states’ political will, their readiness to accept reciprocal enforcement obligations, and the gradual evolution of existing regional arrangements. Accordingly, the analysis treats the proposed architecture as a normative blueprint and feasibility exploration rather than an immediately operational regime. Given uneven doctrinal development and limited publicly accessible case law in Japan and Korea, the comparative assessment is necessarily selective, highlighting areas where further empirical and diplomatic work will be required.