This chapter begins by explaining why international lawyers typically begin discussions about the sources of public international law by referencing Article 38 of the Statute of the International Court of Justice (ICJ). It then introduces treaties and custom, which are the two main sources of law in this field, before discussing other sources, namely general principles of law, decisions of international organizations, unilateral declarations, as well as judicial decisions and the teachings of international legal experts. The chapter ends with a discussion of non-binding instruments, which do not contain binding legal rules, but are nonetheless significant in the international legal field, as they contain norms that impact the behavior of states.

This chapter explores international law relating to the protection of the environment, a relatively new field of international law that covers a broad range of concerns. The pollution of the oceans and the seas, the extinction of animal species, deforestation, and climate change: these are all concerns addressed by international environmental law. This chapter begins by providing a brief overview of the evolution of international environmental law and explains the principal characteristics of this field of international law. It further considers the interrelationship with the concept of sustainable development, which is central to modern approaches toward protecting the environment. It then explores two of the principal concerns addressed by international environmental law: first, the conservation of flora and fauna; and, second, the prevention of pollution and related environmental harm. Furthermore, the chapter discusses compliance and enforcement mechanisms. Lastly, because environmental protection measures often have implications for international trade, it briefly deals with the interrelationship between international environmental law and trade law.

This chapter begins by explaining why international lawyers typically begin discussions about the sources of public international law by referencing Article 38 of the Statute of the International Court of Justice (ICJ). It then introduces treaties and custom, which are the two main sources of law in this field, before discussing other sources, namely general principles of law, decisions of international organizations, unilateral declarations, as well as judicial decisions and the teachings of international legal experts. The chapter ends with a discussion of non-binding instruments, which do not contain binding legal rules, but are nonetheless significant in the international legal field, as they contain norms that impact the behavior of states.

This chapter explores international law relating to the protection of the environment, a relatively new field of international law that covers a broad range of concerns. The pollution of the oceans and the seas, the extinction of animal species, deforestation, and climate change: these are all concerns addressed by international environmental law. This chapter begins by providing a brief overview of the evolution of international environmental law and explains the principal characteristics of this field of international law. It further considers the interrelationship with the concept of sustainable development, which is central to modern approaches toward protecting the environment. It then explores two of the principal concerns addressed by international environmental law: first, the conservation of flora and fauna; and, second, the prevention of pollution and related environmental harm. Furthermore, the chapter discusses compliance and enforcement mechanisms. Lastly, because environmental protection measures often have implications for international trade, it briefly deals with the interrelationship between international environmental law and trade law.

The chapter focuses on the distinction between treaties and other kinds of international instruments. It addresses issues such as why it is necessary to distinguish between treaties and other kinds of international instruments, and what can go wrong when a State or an IO fails to do so. It identifies other kinds of international instruments that are not treaties, their binding status, different scenarios in which it may be difficult to differentiate such instruments and how to overcome such situations. The chapter also offers some suggestions on handling treaties and other kinds of international instruments.