Flexibility provisions in multilateral environmental treaties

In international politics, intergovernmental treaties provide the rules of the game. In this paper, we investigate the rules under which the contents of treaties may be changed, such as rules for adoption and entry into force and rules for dispute resolution. In the first part of the paper, we describe how frequently these rules are used in practice and how they are typically combined, based on 400 treaties and supplementary agreements from the field of international environmental law. Using correspondence analysis, we show that treaty provisions can be represented by a two-dimensional property space. The detected underlying dimensions express varying degrees of institutionalisation and flexibility, respectively. In the second part of the paper, we place amendment rules into the framework of a formal model in the incomplete contracts tradition. It is shown that there exists a trade-off between the risk of too little flexibility, which leads to frequent inefficient breach of the treaty, and the danger that the binding nature of the treaty and hence, the level of commitment by treaty members, is being undermined if the treaty can be amended too easily.