선박 기인 온실가스 배출에 관한 기국의 엄격한 상당한 주의(Stringent Due Diligence) - ITLOS 및 ICJ의 기후변화 권고적 의견 분석을 중심으로 -

Approximately 90 percent of global cargo is transported by sea, rendering maritime shipping an indispensable component of international commerce. Greenhouse gas (GHG) emissions from the shipping sector have emerged as a critical challenge in addressing climate change. However, the exclusive jurisdiction of the flag State, coupled with the widespread practice of flags of convenience (FOC), raises concerns regarding the effective implementation of emission control by flag States. This study examines the obligations of flag States under Part Ⅻ of the United Nations Convention on the Law of the Sea (UNCLOS) through the analytical lens of ‘stringent due diligence’ with reference to the advisory opinions on the International Tribunal for the Law of the Sea (ITLOS) and the International Court of Justice (ICJ) on climate change. It is demonstrated that GHG emissions from vessels constitute marine pollution under UNCLOS and pose a risk of significant transboundary environmental harm under customary international law. Consequently, flag States are required to exercise stringent due diligence―grounded in the precautionary approach―to prevent, reduce and control marine pollution beyond their jurisdiction. In addition, it is important to objectively assess compliance with due diligence against Generally Accepted International Rules and Standards (GAIRS) as the minimum threshold. Furthermore, this research elucidates concrete mechanisms for the operationalization of stringent due diligence by flag States, thereby addressing the normative gap arising from the legal uncertainty inherent in the doctrine of due diligence.