Adopted by Resolution 31/72 of the United Nations General Assembly on 10 December 1976, the ENMOD Convention, of which the UN Secretary-General is the Depositary, was opened for signature at Geneva on 18 May 1977 and entered into force on 5 October 1978. It consists of ten articles and an Annex concerning the Consultative Committee of Experts.
In its Article I the Convention, which is part of disarmament efforts, prohibits the Contracting Parties from engaging in "military or any other hostile use of environmental modification techniques having widespread, long-lasting or severe effects as the means of destruction, damage or injury to any other State Party". Article 2 specifies what is meant exactly by the term "environmental modification techniques".
It should be noted that the adjectives "widespread" "long-lasting" and "severe" are echoed (widespread, long-term, severe) in 1977 Protocol I additional to the 1949 Geneva Conventions (Article 35, para. 3 and Article 55, para. 1) and in preambular para. 4 to the 1980 Convention on Conventional Weapons. Whilst in these two instruments the term "environment" is preceded by the adjective "natural", the ENMOD Convention speaks of the "environment" without any attributive. In addition, the drafters of the ENMOD Convention adopted "Understandings" which are not incorporated into the Convention but which provide additional explanations with regard to some provisions (Articles I, II, III and VIII). The Understanding relating to Article I gives to the terms "widespread", "long-lasting" and "severe" an interpretation limited to the ENMOD Convention and one which is not intended to prejudice the interpretation of the same or similar terms if used in connection with any other international agreement.
Article VIII of the ENMOD Convention makes provision for review conferences to be held at intervals of not less than five years. The first Review Conference took place in Geneva in September 1984.
D.Schindler and J.Toman, The Laws of Armed Conflicts, Martinus Nijhoff Publishers, 1988, pp.164-169.