1 On the development of international environmental protection law see K. Hulme, War Torn Environment: Interpreting the Legal Threshold (2004), 6–10.

2 See, e.g., S. M. Whitby, ‘Anticrop Biological Weapons Programs’, in M. Wheelis, L. Rόsza, and M. Dando (eds.), Deadly Cultures: Biological Weapons since 1945 (2006), 213 at 223.

3 (1976) 1108 UNTS 151. According to Art. I(1) of the ENMOD, each ‘State party undertakes not to engage 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’. Art. II of the ENMOD explains what ‘environmental modification technique’ means, namely, ‘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 of outer space’. Attached to the ENMOD is an Understanding relating to Art. II, which lists on an illustrative basis the ecological phenomena that could be caused by environmental modification techniques. For details see Dinstein, Y., ‘Protection of the Environment in International Armed Conflict’, (2001) 5 Max Planck Yearbook of United Nations Law 524Google Scholar, at 525–30; Schmitt, M. N., ‘Green War: An Assessment of the Environmental Law of International Armed Conflict’, (1997) 22 Yale Journal of International Law 1, 82–5Google Scholar.

4 1977 Protocol Additional to the Geneva Conventions of 12 August 1949, and relating to the Protection of Victims of International Armed Conflicts, 1125 UNTS 3.

5 See Schmitt, supra note 3, at 11–12.

6 1998 Rome Statute of the International Criminal Court, 2187 UNTS 3.

7 See Preamble, para. 8, Arts. 1 and 5 of the ICC Statute.

8 There are other war crimes provisions in the ICC Statute, besides Art. 8(2)(b)(iv), second alternative, which may cover certain aspects of environmental warfare, such as the prohibition of attacks against civilian objects in Art. 8(2)(b)(ii); the prohibition on destroying property of the enemy without military necessity in Arts. 8(2)(b)(xiii), (e)(xii); or the prohibition on using starvation of the civilian population as a method of warfare in Art. 8(2)(b)(xxv). An analysis of these provisions is beyond the scope of this article, which also cannot deal with the question of whether the prohibition in Art. 8(2)(b)(iv), second alternative, of the ICC Statute should be extended to non-international armed conflicts. For effective protection of the natural environment such an extension would certainly be desirable. For examples of destruction of the environment that have been condemned or prosecuted under other war crimes provisions in the past, see Hulme, supra note 1, at 3–4.

9 Dörmann, K., Elements of War Crimes under the Rome Statute of the International Criminal Court: Sources and Commentary (2003), 166CrossRefGoogle Scholar.

10 Koppe, E., The Use of Nuclear Weapons and the Protection of the Environment during International Armed Conflict (2008), 203Google Scholar.

11 See, in particular, Official Records of the UN Diplomatic Conference of Plenipotentiaries on the Establishment of an International Criminal Court, UN Doc. A/CONF.183/13 (1998), Vol. II, www.icc-cpi.int/legaltools/.

12 1969 Vienna Convention on the Law of Treaties, 1155 UNTS 331.

13 Provided that the state parties have not agreed on a different understanding as regards a specific crime, such an ‘interpretation in conformity with general international law’ is accepted also in the field of international criminal law; see Prosecutor v. Tadić, Judgement, Case No. IT-94-1-A, A.Ch., 15 July 1999, para. 287; Ambos, K., Der Allgemeine Teil des Völkerstrafrechts (2002), 381Google Scholar; Kittichaisaree, K., International Criminal Law (2001), 45Google Scholar; G. Werle, Principles of International Criminal Law (2005), margin nos. 160–1.

14 Dörmann, supra note 9, at 162.

15 See, e.g., Art. 52 of Additional Protocol I, which prohibits attacks on civilian objects.

16 Bothe, M., ‘The Protection of the Environment in Times of Armed Conflict. Legal Rules, Uncertainty, Deficiencies and Possible Developments’, (1991) 34 German Yearbook of International Law 54Google Scholar, at 56; Koppe, supra note 10, at 151. But see Verwey, W. D., ‘Protection of the Environment in Times of Armed Conflict: In Search of a New Legal Perspective’, (1995) 8 LJIL 7Google Scholar, at 13, with regard to Art. 55 of Additional Protocol I.

17 See section 3.2., infra.

18 Bellinger, J. B. III and Haynes, W. J. II, ‘A US Government Response to the International Committee of the Red Cross Study Customary International Humanitarian Law’, (2007) 89 International Review of the Red Cross 443Google Scholar, at 455.

19 See Dinstein, supra note 3, at 540; Hulme, supra note 1, at 78; Kiss, A., ‘Les Protocoles additionels aux Conventions de Genève de 1977 et la protection de biens de l'environnement’, in Swinarski, C. (ed.), Studies and Essays on International Humanitarian Law and Red Cross Principles in Honour of Jean Pictet (1984), 181Google Scholar at 187–8.

20 With regard to Arts. 35(3) and 55 of Additional Protocol I, see Witteler, S., Die Regelungen der neuen Verträge des humanitären Völkerrechts und des Rechts der Rüstungsbegrenzung mit direktem Umweltbezug. Waffenwirkung und Umwelt II (1993), 365Google Scholar. On the natural science concept of environment, see, e.g., Eisermann, A. et al. , in Spieker, H. (ed.), Naturwissenschaftliche und völkerrechtliche Perspektiven für den Schutz der Umwelt im bewaffneten Konflikt. Waffenwirkung und Umwelt III (1996), 3Google Scholar at 7–12.

21 See Hulme, supra note 1, at 13 with references.

22 Ibid., at 12. Critically as to the inclusion of humans, see Witteler, supra note 20, at 368–9.

23 In particular Art. 52 of Additional Protocol I.

24 See ILC Draft Code of Crimes against the Peace and Security of Mankind, (1991) 43(2) Yearbook of the International Law Commission 94, at 107, para. 4: ‘The words “natural environment” should be taken broadly to cover the environment of the human race and where the human race develops, as well as areas the preservation of which is of fundamental importance in protecting the environment. These words therefore cover the seas, the atmosphere, climate, forests and other plant cover, fauna, flora and other biological elements.’ See also Dinstein, supra note 3, at 534; Kiss, supra note 19, at 186; C. Pilloud and J. Pictet, in Y. Sandoz, C. Swinarski, and B. Zimmermann (eds.), Commentary on the Additional Protocols of 8 June 1977 to the Geneva Conventions of 12 August 1949 (1987), para. 2126. For more details with regard to Additional Protocol I see H. Spieker, Völkergewohnheitsrechtlicher Schutz der natürlichen Umwelt im internationalen bewaffneten Konflikt. Waffenwirkung und Umwelt I (1992), 381–392; Witteler, supra note 20, at 366–72.

25 Hulme, supra note 1, at 13; J. de Preux, in Sandoz et al., supra note 24, at para. 1451.

26 Werle, supra note 13, at margin no. 1044; S. Oeter, in D. Fleck (ed.), The Handbook of International Humanitarian Law (2008), no. 403, para. 4; W. A. Solf, in M. Bothe, K. J. Partsch, and W. A. Solf, New Rules for Victims of Armed Conflicts: Commentary on the Two 1977 Protocols Additional to the Geneva Conventions of 1949 (1982), 347.

27 Understanding Relating to Article I, www.icrc.org/ihl.nsf/WebART/460--920013?OpenDocument.

28 See Witteler, supra note 20, at 252–3 with further references.

29 Understanding, supra note 27.

30 For references see Witteler, supra note 20, at 377.

31 For references see ibid., at 325–6.

32 Bothe, supra note 16, at 57; Bouvier, A., ‘Protection of the Natural Environment in Time of Armed Conflict’, (1991) 31 International Review of the Red Cross 567CrossRefGoogle Scholar, at 575–6; Dinstein, supra note 3, at 541–2; Kiss, supra note 19, at 189; de Preux, supra note 25, at para. 1454; Witteler, supra note 20, at 253.

33 See Koppe, supra note 10, at 203 with references also from the International Law Commission.

34 Hulme, supra note 1, at 99; Schmitt, supra note 3, at 22–36.

35 Hulme, supra note 1, at 89 with references.

36 According to the preparatory works of Additional Protocol I, the three elements of the threshold damage were ‘extensively discussed’; see Hulme, supra note 1, at 91, who points out, however, that the participating delegations struggled to achieve an acceptable text. That author consequently doubts whether the three terms were ‘ever given “true” meanings’. Ibid., at 89.

37 Witteler, supra note 20, at 380–2.

38 Ibid., at 384–5.

39 Antoine, P., ‘International Humanitarian Law and the Protection of the Environment in Time of Armed Conflict’, (1992) 32 International Review of the Red Cross 517Google Scholar, at 526; Dinstein, supra note 3, at 542; Dinstein, Y., The Conduct of Hostilities under the Law of International Armed Conflict (2004), 191Google Scholar.

40 Witteler, supra note 20, at 383–7.

41 Hulme, supra note 1, at 92–3.

42 Ibid., at 93 (Hulme still contends that this was not the threshold intended in 1977); Schmitt, supra note 3, at 71–2.

43 See also Witteler, supra note 20, at 387.

44 For references see Solf, supra note 26, at 347–8; Witteler, supra note 20, at 325–6.

45 For references see Henckaerts, J.-M. and Doswald-Beck, L., Customary International Humanitarian Law (2005), II/1, ch. 14, paras. 163–187Google Scholar.

46 Supra note 32.

47 See, e.g., Additional Protocol I, Art. 51.

48 Dinstein, supra note 3, at 532; Dinstein, supra note 39, at 183; Kiss, supra note 19, at 190.

49 Dinstein, supra note 3, at 542; Kiss, supra note 19, at 190; de Preux, supra note 25, at paras. 1452, 1454; Solf, supra note 26, at 346; Witteler, supra note 20, at 390.

50 For details see Witteler, supra note 20, at 389–95. See also de Preux, supra note 25, at paras. 1452, 1454.

51 Witteler, supra note 20, at 395.

52 Hulme, supra note 1, at 94; Solf, supra note 26, at 346; for more details and references see Witteler, supra note 20, at 394–5.

53 For details, see Witteler, supra note 20, at 391–2. See also de Preux, supra note 25, at paras. 1452, 1454.

54 ICTY, Final Report to the Prosecutor by the Committee Established to Review the NATO Bombing Campaign against the Federal Republic of Yugoslavia of 14 June 2000, www.un.org/icty/pressreal/nato061300.htm, para. 17.

55 ILC Draft Code of Crimes against the Peace and Security of Mankind, supra note 24, at 107, para. 5.

56 Witteler, supra note 20, at 397.

57 Hulme, supra note 1, at 97; Witteler, supra note 20, at 397.

58 Witteler, supra note 20, at 399. In the same direction Kiss, supra note 19, at 190.

59 Hulme, supra note 1, at 96, 98.

60 Dinstein, supra note 3, at 532–3; Hulme, supra note 1, at 97.

61 Hulme, supra note 1, at 97.

62 Dinstein, supra note 3, at 531–2; Hulme, supra note 1, at 78, 96.

63 Dinstein, supra note 39, at 182; Hulme, supra note 1, at 96–8. See also Witteler, supra note 20, at 397–8, who also argues that damage of the magnitude required by the accumulation of the three criteria will usually also harm humans; ibid., at 399–400. Critically as to this approach, Richards, P. J. and Schmitt, M. N., ‘Mars Meets Mother Nature: Protecting the Environment during Armed Conflict’, (1998–9) 28 Stetson Law Review 1047Google Scholar, at 1085–6.

64 For references see Hulme, supra note 1, at 99.

65 Ibid.; Witteler, supra note 20, at 401.

66 On this problem and others relating to it see P. Lehnes, ‘Probleme der eindeutigen Ermittlung von Ausdehnung, Dauer und Schwere einer Umweltschädigung’, in Spieker, supra note 20, 23 at 30–9.

67 For details on the concept of damage see Eisermann et al., supra note 20, at 13–19; Hulme, supra note 1, at 17–40.

68 Bothe, supra note 16, at 57–8 with further references; Verwey, supra note 16, at 14.

69 Lehnes, supra note 66, at 46–53; Witteler, supra note 20, at 403.

70 Witteler, supra note 20, at 392.

71 According to the Elements of Crimes relating to Art. 8(2)(b)(iv) ICC Statute, num. 3, the perpetrator must positively know at the time of launching the attack that it will cause widespread, long-term, and severe damage to the natural environment. As to problems related to such a standard, see Verwey, supra note 16, at 11–12.

72 Hulme, supra note 1, at 79–80; Witteler, supra note 20, at 411–12; Kiss, supra note 19, at 187.

73 See Prosecutor v. D. Milosević, Case no. IT-98-29, Judgement, T.Ch. III, 12 December 2007, para. 943; Oeter, supra note 26, at no. 444.

74 See also Hulme, supra note 1, at 79–80, who points out that states in their condemnation of the Iraqi actions in the 1990–1 Gulf conflict did not refer to each act of oil spillage or oil-well fire, but to the tactic as a whole; see also Schmitt, supra note 3, at 83–4, with regard to the ENMOD.

75 Hulme, supra note 1, at 97; Witteler, supra note 20, at 394.

76 Final Report to the Prosecutor, supra note 54, at para. 15; R. Arnold, in O. Triffterer (ed.), Commentary on the Rome Statute of the International Criminal Court: Observers’ Notes, Article by Article (2008), Art. 8, margin no. 60; Schmitt, supra note 3, at 71.

77 France has submitted an official interpretative declaration to the ICC Statute, according to which the Statute does not apply to nuclear weapons; www.icc-cpi.int/legaltools/. This position may be explained against the background of a vigorous controversy that evolved during negotiations on the Statute as to whether or not to include a special war crime prohibiting the use of nuclear weapons as such. Since the delegations at the Rome Conference in 1998 could not reach an agreement on this issue, it was finally decided also to drop provisions that would have explicitly criminalized the use of biological and chemical weapons, which some states regarded as the ‘poor man's weapons of mass destruction’; see von Hebel, H. and Robinson, D., ‘Crimes within the Jurisdiction of the Court’, in Lee, R. S. (ed.), The International Criminal Court: The Making of the Rome Statute: Issues, Negotiations, Results (1999), 79Google Scholar at 116; Kirsch, P. and Holmes, J. T., ‘The Rome Conference on an International Criminal Court: The Negotiating Process’, (1999) 93 AJIL 2Google Scholar, at 7–8. As a result, the ICC Statute does not contain any express reference to these three categories of weapon. Nevertheless, their complete exemption from the scope of the Statute cannot be concluded from that. As the preparatory works clearly show, debates at the Rome Conference always focused on the prohibition of biological, chemical, and nuclear weapons per se, i.e. relating to ‘means of warfare’. The question of whether other provisions in the Statute should be applicable to them was apparently never discussed; there is at least no official proof of such a discussion. It can therefore not be assumed that biological, chemical, or, in particular, nuclear weapons were excluded. See also the declarations made by Egypt, New Zealand, and Sweden to the ICC Statute, www.icc-cpi.int/legaltools/.

78 See, e.g., Baxter, R. R., ‘Modernizing the Law of War’, (1977) 78 Military Law Review 165Google Scholar, at 179; Solf, supra note 26, 188–92; F. Kalshoven, ‘Arms, Armaments and International Law’ (1985-II) 191 RCADI 183, at 283; Meyrowitz, H., ‘Stratégie Nucléaire et Droit de la Guerre’, (1979) 83 Revue Général de Droit International Public 905Google Scholar, at 934–5; Oeter, supra note 26, at no. 433; Pilloud and Pictet, supra note 24, at para. 1858. But see H. Fischer, Der Einsatz von Nuklearwaffen nach Art. 51 des I. Zusatzprotokolls zu den Genfer Konventionen von 1949. Völkerrecht zwischen humanitärem Anspruch und militärpolitischer Notwendigkeit (1985), 145–6, 154–5; K. Ipsen, in Bothe, B., Ipsen, K. and Partsch, K.J., ‘Die Genfer Konferenz über humanitäres Völkerrecht. Verlauf und Ergebnisse’, (1978) 38 Zeitschrift für ausländisches öffentliches Recht und Völkerrecht 1Google Scholar, at 43; Witteler, supra note 20, 329–32.

79 See reservation by France to Additional Protocol I of 11 April 2001, para. 2, reservation by United Kingdom of 28 January 1998 lit. (a); as well as the ‘interpretative declarations’ by Belgium, Canada, Germany, Italy, Spain, at www.icrc.org/ihl.nsf/WebSign?ReadForm&id=470&ps=P.

80 But see the declarations by Ireland and the Holy See to Additional Protocol I, at www.icrc.org/ihl.nsf/WebSign?ReadForm&id=470&ps=P.

81 On the question whether the reservations may be invalid for reason of incompatibility with the object and purpose of Additional Protocol I, see Ipsen, supra note 78, at 43–4.

82 Green, L. C., ‘The Environment and the Law of Conventional Warfare’, (1991) 29 Canadian Yearbook of International Law 222Google Scholar, at 228.

83 Solf, supra note 26, at 188–9.

84 Ibid., at 348.

85 Koppe, supra note 10, at 172–4.

86 Hulme, supra note 1, at 97.

87 Legality of the Threat or Use of Nuclear Weapons, Advisory Opinion of 8 July 1996, [1996] ICJ Rep. 226, at 259–60, para. 86.

88 See R. Jennings and A. Watts (ed.), Oppenheim's International Law (1992), I, 275 n. 21.

89 One example is the crime of directing attacks against the civilian population in Art. 8(2)(b)(i) of the ICC Statute.

90 See Dinstein, supra note 3, at 534; Kalshoven, supra note 78, at 283.

91 Supporting an acceptance under customary international law: Henckaerts and Doswald-Beck, supra note 45, I, 152; Werle, supra note 13, at margin no. 1042; cautiously, Final Report to the Prosecutor, supra note 54, para. 15: ‘may . . . reflect current customary law’; similarly, Guldahl, C. G., ‘The Role of Persistent Objection in International Humanitarian Law’, (2008) 77 Nordic Journal of International Law 51CrossRefGoogle Scholar, at 79–80; Oeter, supra note 26, at no. 403, para. 5; rejecting a customary norm, Dinstein, supra note 3, at 534; Green, supra note 82, at 232; Koppe, supra note 10, at 224–35; Schmitt, supra note 3, at 76.

92 According to the ICJ, ‘States must take environmental considerations into account when assessing what is necessary and proportionate in the pursuit of legitimate military objectives’. Nuclear Weapons Advisory Opinion, supra note 87, at 242, para. 30. However, immediately thereafter it is stated that Arts. 35(3) and 55 of Additional Protocol I, in particular, ‘are powerful restraints for all the States having subscribed to these provisions’. Ibid., at 242, para. 31 (emphasis added).

93 Bellinger and Haynes, supra note 18, at 455–60.

94 Henckaerts and Doswald-Beck, supra note 45, I, at 154–5. According to the doctrine of persistent objection, states which do not wish to be bound by an emerging rule of customary law must persistently and openly oppose that rule from the time of its formation. If these conditions are met, the state is not bound by the rule in question. For more details see Guldahl, supra note 91, at 53–5, who argues that in this particular context, France, the United Kingdom, and the United States should rather be considered ‘specially affected states’ and, as a result, it should be concluded that there is no customary norm at all as far as the use of nuclear weapons is concerned. Ibid., at 82–3.

95 It should be noted that the legitimacy of the doctrine of persistent objection in general, and particularly its applicability to international humanitarian law, is a matter of debate. This discussion is, however, beyond the scope of this article. See Guldahl, supra note 91, at 55–62, 83–6 with further references.

96 This position seems to be taken by M. Cottier, in Triffterer, supra note 76, Art. 8, margin no. 180, who dismisses the suggestion of any relevance of reservations to the Geneva Poison Gas Protocol with regard to Art. 8(2)(b)(xviii) of the ICC Statute. However, the Geneva Poison Gas Protocol seems to be a special case. Many of the original reservations, according to which the treaty obligations ended if other states first violated the prohibition, have been withdrawn in the meantime. It can therefore be argued that the prohibition of chemical weapons now exists unconditionally under customary international law; see Henckaerts and Doswald-Beck, supra note 45, I, at 259–63.

97 See also Elements of Crimes for Art. 8 ICC Statute, Introduction, para. 2.

98 Dörmann, supra note 9, at 166–7; Werle, supra note 13, at margin no. 1044.

99 Werle, supra note 13, at margin no. 1044 n. 590.

100 Critically also Cassese, A., International Criminal Law (2008), 96Google Scholar. For arguments in support of the proportionality principle see Schmitt, supra note 3, at 72–4.

101 Dinstein, supra note 3, at 536; Oeter, supra note 26, at no. 403, para. 3; Richards and Schmitt, supra note 63, at 1061–2.

102 V. B. Broomhall, in Triffterer, supra note 76, Art. 22, margin no. 11.

103 See, e.g., Lehnes, supra note 66, at 65; G. Plant, in G. Plant (ed.), Environmental Protection and the Law of War: A ‘Fifth Geneva’ Convention on the Protection of the Environment in Time of Armed Conflict (1992), 37, at 47–8.

104 See Dinstein, supra note 39, at 194; Green, supra note 82, at 232; Hulme, supra note 1, at 170–4; Richards and Schmitt, supra note 63, at 1055–61. As to the evaluation of environmental damage caused by NATO in Kosovo 1999, see Final Report to the Prosecutor, supra note 54, at paras. 14–25.

105 But see Hulme, supra note 1, at 78.

106 Final Report to the Prosecutor, supra note 54, at paras. 19–22; Schmitt, supra note 3, at 55–61.

107 See also Final Report to the Prosecutor, supra note 54, para. 15: ‘Consequently, it would appear extremely difficult to develop a prima facie case upon the basis of these provisions, even assuming they were applicable.’