2.1 The United Nations Convention on the Law of the Sea (‘UNCLOS’)
When turning to consider the legal framework for flag State obligations, a natural starting point is UNCLOS. UNCLOS’ important role in establishing a legal framework governing the oceans and maritime activities is widely acknowledged(1)Ibid n29, page 245. UNCLOS, coming into force in 1994, is almost universal in its application, with 172 parties having ratified the treaty(2)United Nations Division for Ocean Affairs and the Law of the Sea (DOALOS), ‘Chronological lists of ratifications, accessions and successions to the United Nations Convention on the Law of the Sea’https://www.un.org/Depts/los/reference_files/chronological_lists_of_ratifications.htm accessed 10.05.2026.. While UNCLOS addresses a broad range of maritime issues, this thesis focuses on its provisions relating to the protection and preservation of the marine environment, particularly as they apply to activities on the high seas. While UNCLOS provides binding obligations in this respect, it is widely regarded as a framework convention rather than a self-contained regulatory regime, meaning that many of its provisions are written in general terms and are intended to be supplemented by subsequent agreements and general rules of international law(3)Morten Ruud and Geir Ulfstein, ‘Innføring i folkerett’ (2011), 4th edition, Universitetsforlaget, page 66.
UNCLOS divides the ocean into maritime zones, each governed by distinct legal regimes. Of relevance to this thesis are the ABNJ, in particular the high seas, which are defined as all parts of the sea not included in a State’s internal waters, territorial sea, or exclusive economic zone. Since the high seas are characterised by the absence of territorial sovereignty(4)Article 89 UNCLOS, the responsibility for regulating environmentally relevant vessel‑based activities is primarily channelled through flag State jurisdiction(5)Article 92(1) UNCLOS , making this the central jurisdictional basis for assessing environmental protection obligations, including EIA.