Related Rule
United States of America
Practice Relating to Rule 147. Reprisals against Protected Objects
Section E. Natural environment
The US Air Force Commander’s Handbook (1980), under the heading “Persons and Things Not Subject to Reprisals”, lists a number of persons and objects protected under the 1949 Geneva Conventions against whom reprisals are prohibited. It adds, however: “A Protocol to the 1949 Geneva Conventions would expand this list to include … the natural environment. The United States signed this Protocol in 1977, but has not yet ratified it. Consult the Staff Judge Advocate for further guidance.” 
United States, Air Force Pamphlet 110-34, Commander’s Handbook on the Law of Armed Conflict, Judge Advocate General, US Department of the Air Force, 25 July 1980, § 8-4(c).
In 1987, in submitting the 1977 Additional Protocol II to the US Senate for advice and consent to ratification, the US President announced his decision not to ratify the 1977 Additional Protocol I, stating, inter alia, that the Additional Protocol I “fails to improve substantially the compliance and verification mechanisms of the 1949 Geneva Conventions and eliminates an important sanction against violations of those Conventions”. 
United States, Message from the US President transmitting the 1977 Additional Protocol II to the US Senate for advice and consent to ratification, Treaty Doc. 100-2, 29 January 1987.
In 1987, the Deputy Legal Adviser of the US Department of State stated that the United States did not support “the prohibition on reprisals in article 51 [of the 1977 Additional Protocol I] and subsequent articles” and did not consider it part of customary law. 
United States, Remarks of Michael J. Matheson, Deputy Legal Adviser, US Department of State, The Sixth Annual American Red Cross-Washington College of Law Conference on International Humanitarian Law: A Workshop on Customary International Law and the 1977 Protocols Additional to the 1949 Geneva Conventions, American Journal of International Law and Policy, Vol. 2, 1987, p. 426.
In 1992, prior to the adoption of a UN General Assembly resolution on the protection of the environment in times of armed conflict, Jordan and the United States submitted a memorandum entitled “International Law Providing Protection to the Environment in Times of Armed Conflict” which provided, inter alia:
For States parties the following principles of international law, as applicable, provide additional protection for the environment in times of armed conflict: Article 55(2) of Additional Protocol I prohibits States parties from attacking the natural environment by way of reprisals. 
Jordan and 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(d).
In its written statement submitted to the ICJ in the Nuclear Weapons case in 1995, the United States stated:
Various provisions of Additional Protocol I contain prohibitions on reprisals against specific types of persons or objects, including … the natural environment (Article 55(2)) … These are among the new rules established by the Protocol that … do not apply to nuclear weapons. 
United States, Written statement submitted to the ICJ, Nuclear Weapons case, 20 June 1995, p. 31.