Sea-Level Rise and Maritime Zones: The Legal Question Behind the 2024-2025 Climate Advisory Opinions
Sea-level rise has moved from a scientific concern to a live question before international courts and tribunals. The International Tribunal for the Law of the Sea issued an advisory opinion in 2024 on states' climate obligations under UNCLOS, the International Court of Justice followed with its own advisory opinion on climate change and international law in 2025, and the Pacific Islands Forum has continued to issue declarations asserting that member states' maritime zones remain fixed regardless of physical coastline change. Each of these developments turns on the same underlying legal question: can a coastal state's baselines — and the territorial sea, exclusive economic zone and continental shelf measured from them — stay legally stable even as the coastline itself moves under the UN Convention on the Law of the Sea?
Sea-Level Rise and the Legal Stability of Maritime Zones, published by Oxford University Press, is the first monograph to treat that question as a distinct legal framework rather than a side issue within the older "ambulatory versus fixed baselines" debate. Author Dr. Frances Anggadi, of the Australian National Centre for Ocean Resources and Security, draws on an extensive body of state practice and domestic baseline legislation to argue that UNCLOS can be interpreted — without formal amendment — to preserve maritime entitlements against sea-level rise.
For practitioners, the book has direct application in at least three settings: government legal advisers drafting or defending a state's baseline declaration can use its treaty-interpretation methodology as a template; maritime boundary negotiators facing a dispute complicated by coastal erosion can draw on its analysis of state practice across multiple jurisdictions; and counsel briefing a tribunal or court on climate-related law of the sea questions now have a single reference synthesising the doctrinal debate.
For academic and government law libraries supporting international law, law of the sea or climate law research, this is a title whose relevance will only grow as more coastal and Pacific states formalise their own baseline positions and as further advisory proceedings before international courts engage directly with the questions the book addresses.
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Q&A
Q: What legal question does this book address?
A: Whether a coastal state's maritime zones — territorial sea, exclusive economic zone and continental shelf — can remain legally stable under UNCLOS even as the physical baseline used to measure them shifts due to sea-level rise.
Q: Does the book conclude that UNCLOS needs to be amended?
A: No. It argues that existing UNCLOS provisions can be applied through interpretative practice and consistent state practice to preserve maritime entitlements without a formal amendment to the Convention.
Q: How is this connected to recent international court proceedings?
A: The book's subject matter is directly relevant to the questions addressed in ITLOS's 2024 advisory opinion and the ICJ's 2025 advisory opinion on states' climate obligations under international law, both of which touch on the stability of maritime entitlements.
Q: Who is the author?
A: Dr. Frances Anggadi, a researcher at the Australian National Centre for Ocean Resources and Security, University of Wollongong, and Editor-in-Chief of the Australian Journal of Maritime and Ocean Affairs.
Q: Where can I buy Sea-Level Rise and the Legal Stability of Maritime Zones?
A: You can order Sea-Level Rise and the Legal Stability of Maritime Zones directly from CLNZ Books, with worldwide shipping and secure payment by card, PayPal or bank transfer.