Related Rule
United States of America
Practice Relating to Rule 45. Causing Serious Damage to the Natural Environment
Section B. Environmental modification techniques
In 1992, in a statement at the Second ENMOD Review Conference, the United States expressed the view that:
The [1976 ENMOD] Convention is not an Environmental Protection Treaty; it is not a treaty to prohibit damage to the environment resulting from armed conflict. Rather, the [1976 ENMOD] Convention fills a special, but important niche reflecting the international community’s consensus that the environment itself should not be used as an instrument of war. 
United States, Statement of 15 September 1992 at the Second ENMOD Review Conference, Geneva, 14–21 September 1992.
In 1992, in a memorandum annexed to a letter to the Chairman of the Sixth Committee of the UN General Assembly, Jordan and the United States noted that for those States party to the 1976 ENMOD Convention, the following principles of international law provide additional protection for the environment in times of armed conflict:
The 1977 Convention (ENMOD) prohibits States parties from engaging in military or any other hostile use of environmental modification techniques (i.e., any techniques for changing – through the deliberate manipulation of natural processes – the dynamics, composition or structure of earth, its biota, lithosphere, hydrosphere and atmosphere, or of outer space) having widespread, long-lasting or severe effects as the means of destruction, damage or injury to any other State party. 
United States, International Law Providing Protection to the Environment in Times of Armed Conflict, annexed to Letter dated 28 September 1992 to the Chairman of the Sixth Committee of the UN General Assembly, UN Doc. A/C.6/47/3, 28 September 1992, § 2(e).