Despite the extraordinary proliferation of instruments of international environmental law since the 1972 UNCHE Conference in Stockholm, it appears that diverse forces are acting to maintain the internal coherence of this sub-field of international law, as well as its position firmly within the international law system. A range of institutions and processes ensure the continuing unitary nature of international environmental law within a unitary system of international law, notably including the universalist instincts of the International Court of Justice, the codification routinely undertaken by the International Law Commission, and the universal, pervasive and indivisible character of increasingly relevant human rights norms. These processes of “convergence” act to unify and enrich the fabric of the increasingly elaborate and sophisticated complex of rules, principles and institutional structures comprising international environmental law, while suggesting its growing developmental maturity after 50 years of frenetic evolution and supporting its continuing coherent elaboration.