In order to examine differential treatment for developing countries in international environmental law it is helpful to understand the sources from which that law is derived. The sources also enable us to tell whether a particular doctrine, principle, or rule actually has the force and effect of law, 1 though as this section will illustrate, this can be quite controversial with regard to what qualifies as customary international law.
International environmental law has the same sources as international law, as it is a specialized branch of that general law. 2 The traditional and generally accepted sources of international law are laid down in Article 38(1) of the Statute of the International Court of Justice. 3 This article is a provision of a legal instrument that is meant to govern the International Court of Justice (ICJ), but has come to apply generally, defining legal authority upon which decision-makers decide cases and advocate policies. 4 Article 38(1) denotes the sources of international law as follows: (a) international conventions, whether general or particular; (b) international custom, as evidence of a general practice accepted as law; (c) general principles of law, recognized by civilized nations; and (d) judicial decisions and teachings of the most highly qualified publicists, as subsidiary means for the determination of rules of law. 5
Treaties are the most frequently used method for creating binding international environmental law. Treaties are defined in the Vienna Convention on the Law of Treaties, as "an international agreement concluded between States in written form and governed by international law, whether embodied in a single instrument or in two or more related instruments and whatever its particular designation." 6 Article 11 of this treaty states that "[t]he consent of a State to be bound by a treaty may be expressed by signature, . . . ratification, . . . or by any other means if so agreed." 7 This emphasizes