Abstract This article examines the development of the due diligence obligation to protect and preserve the marine environment under the United Nations Convention on the Law of the Sea (UNCLOS). It does so specifically in the International Tribunal for the Law of the Sea's (ITLOS) Advisory Opinion Submitted by the Commission of Small Island States on Climate Change and International Law . The article first provides a conceptual framework for what ITLOS developed as a result‐oriented due diligence obligation to protect and preserve the marine environment, with a focus on the requirements due diligence now places on States. Since ITLOS refrained from assessing States' measures in concreto , the article then applies the result‐oriented due diligence, substantiating States' obligations and responsibility in combating climate effects on the marine environment. It finds that the objectives and requirements of the result‐oriented due diligence not only require States to set an ambitious target in their nationally determined contributions (NDCs) that reflects the objective the 1.5°C temperature goal, but also to implement their NDCs. Failure to do so would amount to not exercising due diligence and could trigger State responsibility enforceable through the compulsory dispute settlement mechanism under UNCLOS.
Roeben et al. (Fri,) studied this question.