The Legal Effect of the ‘Paris Rulebook’ under the Doctrine of Treaty Interpretation

This part of the book examines the legal effect of the so called Paris Rulebook under the doctrine of treaty interpretation. The Paris Rulebook is a composition of decisions and annexes, adopted by the ‘Conference of Parties serving as the Meeting of the Parties under the Paris Agreement’ (CMA) in Katowice in 2018. These further decisions play a significant role for the implementation of the Paris Agreement, which in itself does not explain in sufficient detail how Parties intend to achieve the ambitious temperature goal of holding the increase in the global average temperature to well below 2°C above pre-industrial levels, and more ambitiously, to 1.5°C. The role of the Paris Rulebook will be much greater if it can be shown that it has a decisive legal effect in accordance with general international law. In this chapter, the legal effect that the Paris Rulebook has for the implementation of the Paris Agreement is looked at on the basis of a conceptual analysis of Art. 31 of the 1969 Vienna Convention on the Law of Treaties (VCLT). The International Law Commission (ILC) of the United Nations has adopted draft conclusions to establish the legal effect of subsequent agreements of Parties for the interpretation of a treaty, based on Art. 31 and Art. 32 of the VCLT. These draft conclusions offer analytical tools derived from state practice and international jurisprudence under Art. 31 VCLT. The interpretative effect of subsequent agreement of Parties on key parts of the Paris Agreement can thus be examined with these criteria recognised in international law and a legal effect on Parties’ nationally determined contributions (NDCs), their accounting for and reporting of greenhouse gas (GHG) emissions, and the operation of the Paris Agreement’s oversight mechanism such as the so called ‘global stocktake’ and the compliance procedure can be identified.