Sources of International Environmental Law
Mostly the same ones as IL but IEL has also served as a lab to rethink these.
Statute of the International Court of Justice
The starting point traditionally. It mentions→
International Conventions/Treaties/Agreements
These terms interchangeably design the same reality, an agreement between states and sometimes between states and IOs or only IOs. These can be general or particular, as long as they establish rules expressly recognised by contesting states. In the case of IEL, the objective is to protect or basically to regulate what pertains to the environment.
International Custom
Mystical source… Basically as the evidence of a general practice accepted as law. Not always written, even though right now many treaties try to codify it (representatively). But it is by definition not written and is derived from the practice of states. This conduct must be general (majority of states), uniform (majority of states do it in the same way) and old (continuity in time, constantly).
This requires a feeling of being required by law→ an opinio iuris. Basically the psychological component. Such component can be extrapolated from declarations (different types of statements in front of courts or at the United Nations f.ex.).
Principles
Principles like that of equality before the law are common to every system of law. They also exist in IL (recognised by every nation) and, therefore, in IEL. But IEL isn’t as made… and as such, some principles can be debated in what pertains to them really being one.
Judicial decisions
And also doctrine, as they can help to interpret and determine the law. When the system was born there was a vacuum, and these helped fill it. It can be called jurisprudence or case law in what pertains to court decisions.
Soft Law
Not mentioned in Art. 38 of the statute of the ICJ, but also applicable to IEL. Sometimes a precursor.