Related Rule
New Zealand
Practice Relating to Rule 45. Causing Serious Damage to the Natural Environment
New Zealand’s Military Manual (1992) states:
Care shall be taken in warfare to protect the natural environment against widespread, long-term and severe damage. This protection includes a prohibition of the use of methods or means of warfare which are intended or may be expected to cause such damage to the natural environment and thereby to prejudice the health or survival of the population. 
New Zealand, Interim Law of Armed Conflict Manual, DM 112, New Zealand Defence Force, Headquarters, Directorate of Legal Services, Wellington, November 1992, §§ 505(1) and 614(1).
[emphasis in original]
Under New Zealand’s International Crimes and ICC Act (2000), war crimes include the crimes defined in Article 8(2)(b)(iv) of the 1998 ICC Statute. 
New Zealand, International Crimes and ICC Act, 2000, Section 11(2).
In its written statement submitted to the ICJ in the Nuclear Weapons case in 1995, New Zealand stated:
Protection of the global environment is now a major concern of the international community, with widespread support for progressive development of international treaty law in this area. The condemnation of the large-scale environmental damage wreaked upon Kuwait by Iraqi forces during the “Gulf War” in 1991 was in part a reflection of this concern. It would be a matter for consideration by the Court whether the avoidance of widespread, long-term and severe damage to the environment during war could yet be regarded as itself a rule of customary law. 
New Zealand, Written statement submitted to the ICJ, Nuclear Weapons case, 20 June 1995, § 73.
In its oral pleadings before the ICJ in the Nuclear Weapons case in 1995, New Zealand invoked a principle of IHL whereby “parties to a conflict must not use methods or means of warfare which are intended or may be expected to cause widespread, long-term and severe damage to the natural environment”. 
New Zealand, Oral pleadings before the ICJ, Nuclear Weapons case, 9 November 1995, Verbatim Record CR 95/28, p. 27.
New Zealand’s Military Manual (1992) states:
Parties to the [1976 ENMOD] Convention have undertaken not to engage in any military or hostile use of environmental modification techniques which would have widespread, long-lasting or severe effects as the means of destruction, damage or injury to any other States Party to the Convention.
“Environmental modification techniques” are defined by ENMOD as any technique for changing, through the deliberate manipulation of natural processes, the dynamics, composition or structure of the earth, including its biota, lithosphere, hydrosphere and atmosphere or outer space. Care shall be taken in warfare to protect the natural environment against widespread, long-term and severe damage. This protection includes a prohibition of the use of methods or means of warfare which are intended or may be expected to cause such damage to the natural environment and thereby to prejudice the health or survival of the population. 
New Zealand, Interim Law of Armed Conflict Manual, DM 112, New Zealand Defence Force, Headquarters, Directorate of Legal Services, Wellington, November 1992, §§ 505(2)–(3) and 614(2)–(3).
[emphasis in original]