Abstract This Model studies the topic of normative hierarchy in the international law system with an emphasis on environmental laws. Normative hierarchy of the international rules is an important topic in general international laws. One of the important characteristics of any legal rule is its level of validity. Since all rules of law have binding effects, they are all considered as binding rules. The question here is to what extent a legal rule is binding, i.e. how valid a rule is. Due to differences in their levels of being binding, it is obvious that the rules with higher binding nature have higher status and are more valid. In general international law, the highest rate of validity belongs to preemptory norms. After the preemptory norms which are at the top of the hierarchy, come the erga omnes obligations with a considerable rate of validity. It is evident that in case of conflict among rules with different validity degrees, the lower-order rules are doomed to become invalid in the face of their higher-order counterparts. This difference in the status of legal rules can be investigated in all branches of international law including international environmental law. Although international environmental law is an emergent and very recent branch of general international law, grading of legal rules with respect to their validity still exists in this branch of law. Investigating the degree of validity and legal status of the principles and rules in the international environmental law is the main topic pursued in this thesis. This topic is so important since today we are faced with a considerable number of valid yet conflicting legal rules. Thus, it becomes necessary to resolve the existing conflicts and one important criterion in this regard is to pay attention to the degree of a rule's validity. This thesis particularly takes into account the investigation of validity and status in the rules of international environmental law. There are not any specific studies carr
