On July 12, the International Tribunal for the Law of the Sea upheld the Philippine government’s challenge to China’s sweeping claim that it had “since time immemorial” ruled the seas between Hainan and Singapore. But almost overlooked in media reportage of the tribunal’s rulings were important clarifications of provisions of the United Nations Convention on the Law of the Sea, or UNCLOS, on the protection of the marine environment. However the South China Sea showdown turns out, the tribunal’s rulings will bear importantly on future argument over the environment and ecosystem protection obligations of states everywhere.