The law of the sea, one of the oldest and most venerable fields of international law, is built on the assumption of environmental stability; that the vast seas, though sometimes tempestuous, are in their essence constant, immutable, dependable, and perpetual. Yet in the Anthropocene, the geological epoch to which humanity has lent its name, the seas are rapidly warming, expanding and rising, and their chemistry is changing, souring, acidifying as they absorb humanity's carbon wastes. Added to this marine environmental transformation are new challenges to the stable legal foundations of the order of the seas, as rising powers seek exception from the rules, principles and processes of the law of the sea set out in the 1982 UN Convention on the Law of the Sea (UNCLOS), the 'constitution' of the oceans. Yet for all tempest, flotsam and jetsam swirling around the contemporary law of the sea, there are reasons to be hopeful that the storm warnings will be heeded, and that we will avoid the fate of the ancient mariner, bound to repent for his senseless shooting of a wandering albatross. To offer one, very significant example, negotiations are now underway on a new global treaty to protect marine biodiversity on the high seas. Such an agreement would breathe new and more diverse life into the notions of common heritage and common concern which have animated the modern law of the sea, and which need to do much more work if we are to maintain a healthy and peaceful ocean environment for the centuries to follow.