What is the meaning of a “common legal framework”?
Does this term have any precedent, either in the UNFCCC or in other international law contexts?
“Common legal framework” is not a term of international law that implies any particular meaning. For example, agreeing to develop a “common legal framework” does not imply either that what is developed will be binding or not binding. If what is in fact developed in the future is intended to be legally binding, that will be made evident by the form and terms of the framework that is developed.
As a general matter, it should be noted that agreements between countries to agree on something in the future are inherently unenforceable, so even if there were an agreement or COP decision to agree in the future on a “binding common legal framework”, that would not assure as a matter of law any agreement, let alone an agreement with a specific content. The UN Framework Convention is of course binding, but the term “framework” was used in the title at least partly to convey that the Convention was in important ways simply a framework for agreeing on more specific commitments.