Amendment of treaties – general rules
General rules regarding the amendment of treaties are embodied in the Vienna Convention on the Law of Treaties (1969).
A treaty may be amended by agreement between its Parties. Unless provided otherwise in a treaty, every Party to a treaty, whether a Convention or a Protocol thereto, is entitled to participate in the negotiations of an amendment to that treaty. Following adoption of an amendment, and unless provided otherwise in the treaty, any Party to the treaty may express its consent to be bound by the new amendment.
Amendment of the Basel Convention (Article 17 (5))
Amendment of the Basel Convention is dealt with in Article 17 of the Convention. Entry into force of amendments of the Convention is dealt with under paragraph 5 of that Article, which provides that:
"Instruments of ratification, approval, formal confirmation or acceptance of amendments shall be deposited with the Depositary. Amendments adopted in accordance with paragraphs 3 or 4 above shall enter into force between Parties having accepted them on the ninetieth day after the receipt by the Depositary of their instrument of ratification, approval, formal confirmation or acceptance by at least three-fourths of the Parties who accepted them or by at least two thirds of the Parties to the protocol concerned who accepted them, except as may otherwise be provided in such protocol. The amendments shall enter into force for any other Party on the ninetieth day after that Party deposits its instrument of ratification, approval, formal confirmation or acceptance of the amendments."
By decision BC-10/3 adopted in 2011 by the tenth meeting of the Conference of the Parties, Parties agreed, without prejudice to any other multilateral environmental agreement, that the meaning of paragraph 5 of Article 17 of the Basel Convention should be interpreted to mean that “acceptance of three-fourths of those parties that were parties at the time of the adoption of the amendment is required for the entry into force of such amendment, noting that such an interpretation of paragraph 5 of Article 17 does not compel any party to ratify the Ban Amendment.”