Climate Change Impacts on the Ocean: A Study with Special Reference to the 1982 UNCLOS, Sea-Level Rise and Maritime Boundaries

Abstract

The 1982 United Nations Convention on the Law of the Sea was adopted before climate change became a central concern of international environmental law, and it is not a climate treaty. Its provisions on the protection of the marine environment nevertheless supply a working framework for climate-related marine harm, and the 2024 Advisory Opinion of the International Tribunal for the Law of the Sea has strengthened that link by recognizing that anthropogenic greenhouse-gas emissions can constitute pollution of the marine environment within the meaning of the Convention. This paper examines what accelerating sea-level rise means for that framework. It traces the physical drivers of sea-level change, distinguishing global mean rise from local relative change produced by subsidence, sedimentation, tectonic activity and coastal morphology, and sets out the environmental, economic and human consequences, including displacement from low-lying States and the gap in international protection that leaves climate migrants outside existing refugee law. It then turns to the questions that matter most for the law of the sea: whether retreating coastlines and disappearing reef features unsettle baselines, maritime zones and statehood itself. The paper argues that the decisive distinction is between baselines and established boundaries. Baselines follow physical geography; boundaries fixed by agreement or adjudication do not, and the Bay of Bengal arbitration supports their stability. Reconciling physical change with legal certainty is the central task for maritime governance.