Precautionary in International Law: A Customary Principle or a General Principle of Law?

It took humankind a long time to realize its inability to understand different aspects of environmental risks and find that it would bear irreversible damage if such a risk occurs.
Knowing the vulnerability of the environment and the limitations of science to accurately predict threats to it, led to emerging the precautionary principle. This concept has stemmed from domestic legal systems and is being developed in international law. Various Formulations of the principle and its including in binding and nonbinding international instruments in varied fields have resulted in controversial discussions between states, Tribunals and Commentators on Its legal status in International law. They are at least divided into two groups: some who are on customary status of the principle and some who entitle it as a general principle of law.
This paper examines different views towards the legal status of the precautionary principle in International law and try to give a reasonable opinion at the end.