Unilateral seabed mining outside the International Seabed Authority does not erase pollution obligations; it concentrates them on the licensing State. That is the sharp, useful conclusion of recent legal scholarship, and it reframes a debate that has spent too long on the narrow question of who owns the nodules. The United States has begun licensing commercial recovery of polymetallic nodules in the Clarion-Clipperton Zone under its own statute, while the Authority's exploitation regulations remain unadopted. Most commentary has treated this as an allocation problem, whether a nonparty can acquire good title in the Area. The more consequential question is environmental: which duties bind a nonparty that mines there, and on what legal basis.
The answer, argued persuasively, is that the pollution duties of Part XII of the United Nations Convention on the Law of the Sea are severable from the allocative bargain of Part XI. Prevention, due diligence, and prior environmental impact assessment bind the nonparty as customary international law, evidenced by its own practice and its obligations under the 1958 Convention on the High Seas. The treaty-specific Article 209(2) does not bind it, but it serves as evidence of what customary due diligence demands in the Area. This matters for our readers because it means the legal floor is not as low as unilateral licensing suggests. A State that leaves the referent institution while remaining bound by the rule of reference engages in what the scholarship names *referential arbitrage*, and the benchmark on which that arbitrage relies proves thinner than claimed, but not empty. This is not a theoretical nicety. It connects directly to the broader governance questions we have traced in Navigating Autonomy at Sea: Balancing Coastal Rights with Ocean Data Integrity and the climate-ocean convergence examined in The ICJ anchors ocean law into the climate governance framework. The pattern is consistent: legal regimes built for one era are being stress-tested by technological and economic pressure, and the gaps are not neutral.
The geography on which unilateral licensing depends is also defective. A licence draws a boundary; a plume does not observe it. Sediment and discharge plumes from nodule recovery will travel across the Area, and the 1972 London Convention excluded seabed mining discharge on the assumption that a seabed regime would govern it. That carve-out was extended on credit, and unilateral licensing never redeems it. Exit from the Authority does not remove State responsibility; it concentrates it on the licensing State. That is a practical point for policymakers and investors alike: the legal risk does not disappear with a domestic permit, it migrates upward to the State that issued it. The scholarship closes with measures that require no accession, including an advisory request the Authority's Council may make on its own motion. That is the detail to watch. An advisory opinion would not settle ownership, but it could calibrate the customary standard of due diligence in the Area, and it would do so without waiting for the United States to join the Convention. The question is whether the Council will act, or continue to let unilateral licensing define the baseline by default.