‘Climate change law’ is considered by a number of legal scholars as an emergent novel discipline. The question, then, is whether the advent (and future prospect) of climate change has resulted in a coherent autonomous new body of law, be it a nascent one; or is it nothing more or less than the application of existing national and international environmental law to climatic problems? It is perhaps worth recalling that international environmental law itself only ascended to the rank of a recognized discipline of its own in the 1990s, over considerable academic scepticism at the time. Not un-similarly, the ongoing new project of the UN International Law Commission (ILC) for the drafting of guidelines on “protection of the atmosphere” has met with resistance from a few powerful States claiming that there is no need for further codification of international law in this field. Yet, considering our common interest in conserving the quality of the Earth’s atmosphere and climate, the ILC project may indeed encourage further development of a concept of inter-generational “planetary trusteeship”, owed by States as public trustees to present and future citizens as the beneficiaries.