Rule 45. The use of methods or means of warfare that are intended, or may be expected, to cause widespread, long-term and severe damage to the natural environment is prohibited. Destruction of the natural environment may not be used as a weapon.
Volume II, Chapter 14, Section C.
State practice establishes this rule as a norm of customary international law applicable in international, and arguably also in non-international, armed conflicts. It appears that the United States is a “persistent objector” to the first part of this rule. In addition, France, the United Kingdom and the United States are persistent objectors with regard to the application of the first part of this rule to the use of nuclear weapons.
Article 35(3) of Additional Protocol I prohibits the use of “methods or means of warfare which are intended, or may be expected to cause, widespread, long-term and severe damage to the natural environment”.
This prohibition is also contained in Article 55(1) of Additional Protocol I.
These provisions were clearly new when they were adopted. Upon ratification of Additional Protocol I, France and the United Kingdom stated that the risk of environmental damage falling within the scope of these provisions must be assessed “objectively on the basis of the information available at the time”.
However, since then, significant practice has emerged to the effect that this prohibition has become customary. This prohibition is set forth in many military manuals.
Causing widespread, long-term and severe damage to the environment is an offence under the legislation of numerous States.
This practice includes that of States not, or not at the time, party to Additional Protocol I.
Several States indicated in their submissions to the International Court of Justice in the Nuclear Weapons case
and Nuclear Weapons (WHO) case
that they considered the rules in Articles 35(3) and 55(1) of Additional Protocol I to be customary.
In the same context, other States appeared to be of the view that these rules were customary as they stated that any party to a conflict must observe this rule, or must avoid using methods or means of warfare that would destroy or could have disastrous effects on the environment.
The Report on the Practice of Israel, which is not a party to Additional Protocol I, states that the Israeli Defense Forces do not utilize or condone the use of methods or means of warfare which are intended, or may be expected, to cause widespread, long-term and severe damage to the environment.
The United States, in response to an ICRC memorandum on the applicability of IHL in the Gulf region in 1991, stated that “U.S. practice does not involve methods of warfare that would constitute widespread, long-term and severe damage to the environment”.
Other relevant practice includes condemnations of States not, or not at the time, party to Additional Protocol I for their alleged “ecocide” or “massive destruction of the environment” or for having violated Articles 35(3) and 55(1) of Additional Protocol I.
The prohibition on inflicting widespread, long-term and severe damage to the natural environment is also repeated in the Guidelines on the Protection of the Environment in Times of Armed Conflict and the UN Secretary-General’s Bulletin on observance by United Nations forces of international humanitarian law.
In its working paper on war crimes submitted in 1997 to the Preparatory Committee for the Establishment of an International Criminal Court, the ICRC considered as a war crime “wilfully causing widespread, long-term and severe damage to the natural environment”.
The final text agreed for the war crime included in the Statute of the International Criminal Court defines this war crime as “intentionally launching an attack in the knowledge that such attack will cause … widespread, long-term and severe damage to the natural environment which would be clearly excessive in relation to the concrete and direct overall military advantage anticipated”.
The Statute thus establishes an additional condition with respect to the criminalization of the prohibition contained in this rule.
There is, however, a certain amount of practice that indicates doubt as to the customary nature of the rule in Additional Protocol I, in particular with respect to the phrase “may be expected to cause”. The submissions of the United Kingdom and the United States to the International Court of Justice in the Nuclear Weapons case
stated that Articles 35(3) and 55(1) of Additional Protocol I were not customary.
The Court itself appeared to consider the rule not to be customary as it only referred to the applicability of this provision to “States having subscribed to these provisions”.
Upon ratification of the Convention on Certain Conventional Weapons, which recalls, in its preamble, the rule in Articles 35(3) and 55(1) of Additional Protocol I, both France and the United States made a statement of interpretation to the effect that this was not a customary rule.
Less clear is the Final Report of the Committee Established to Review the NATO Bombing Campaign Against the Federal Republic of Yugoslavia, which stated that Article 55 of Additional Protocol I “may … reflect current customary law”.
The problem of the customary law nature of the rule, as articulated in Additional Protocol I, seems to turn on the position of France, the United Kingdom and the United States, which have a certain amount of practice indicating their acceptance of the rule provided that it applies to conventional weapons and not to nuclear weapons. This is made clear by the UK LOAC Manual and the US Air Force Commander’s Handbook,
and by the reservations made by France and the United Kingdom upon ratifying Additional Protocol I to the effect that the Protocol did not apply to nuclear weapons.
This position, combined with the statements of France and the United Kingdom that Articles 35(3) and 55(1) of Additional Protocol I are not customary,
means that the opinio juris
of these three States is that these rules, of themselves, do not prohibit the use of nuclear weapons.
Practice, as far as methods of warfare and use of conventional weapons are concerned, shows a widespread, representative and virtually uniform acceptance of the customary law nature of the rule found in Articles 35(3) and 55(1) of Additional Protocol I. The contrary practice of France, the United Kingdom and the United States in this regard is not totally consistent. Their statements in some contexts that the rules are not customary contradict those made in other contexts (in particular in military manuals) in which the rule is indicated as binding as long as it is not applied to nuclear weapons.
As these three States are not “specially affected” States as far the infliction of this type of damage is concerned, this contrary practice is not enough to have prevented the emergence of this customary rule. However, these three States are specially affected as far as possession of nuclear weapons is concerned, and their objection to the application of this specific rule to such weapons has been consistent since the adoption of this rule in treaty form in 1977. Therefore, if the doctrine of “persistent objector” is possible in the context of humanitarian rules, these three States are not bound by this specific rule as far as any use of nuclear weapons is concerned. However, it needs to be noted that this does not prevent any use of nuclear weapons being found unlawful on the basis of other rules, for example the prohibition of indiscriminate attacks (see Rule 11) and the principle of proportionality (see Rule 14).
There is extensive State practice prohibiting the deliberate destruction of the natural environment as a form of weapon. The ENMOD Convention prohibits the deliberate modification of the environment in order to inflict widespread, long-lasting or severe effects as a means of destruction, damage or injury to another State party.
The difference between this provision and the one in Additional Protocol I is that the latter refers primarily to the effects, whereas the ENMOD Convention refers to the deliberate use of a technique to modify the environment. Whether the provisions in the ENMOD Convention are now customary is unclear. On the one hand, the military manuals of Israel, South Korea and New Zealand appear to indicate that the treaty only binds parties to it.
On the other hand, Indonesia, which is not a party to the ENMOD Convention, states this rule in its military manual.
The Guidelines on the Protection of the Environment in Times of Armed Conflict includes this rule.
The UN General Assembly, in a resolution on the United Nations Decade of International Law adopted in 1994 without a vote, invites all States to disseminate these Guidelines widely.
At the Second ENMOD Review Conference in 1992, the United States stated that the Convention reflected “the international community’s consensus that the environment itself should not be used as an instrument of war”.
In addition to the specific rules contained in the ENMOD Convention, significant practice exists prohibiting a deliberate attack on the environment as a method of warfare. The legislation of several States criminalizes “ecocide”.
Estonia’s Penal Code prohibits affecting the environment as a method of warfare.
Yugoslavia condemned what it called “ecocide” in connection with the NATO attack on a petrochemical plant in 1999.
Iraq, in a letter to the UN Secretary-General in 1991, stated that it would not exploit the environment and natural resources “as a weapon”.
Kuwait, in a letter to the UN Secretary-General the same year, stated that the environment and natural resources must not be used “as a weapon of terrorism”.
During a debate in the Sixth Committee of the UN General Assembly in 1991, Sweden, referring to the destruction of the environment by Iraqi forces, said that this was an “unacceptable form of warfare in the future”.
In the same context, Canada stated that “the environment as such should not form the object of direct attack”.
Also noteworthy is the declaration adopted in 1991 by the OECD Ministers of the Environment condemning Iraq’s burning of oil fields and discharging of oil into the Gulf as a violation of international law and urging Iraq to cease resorting to environmental destruction as a weapon.
Therefore, irrespective of whether the provisions of the ENMOD Convention are themselves customary, there is sufficiently widespread, representative and uniform practice to conclude that the destruction of the natural environment may not be used as a weapon.
The applicability of both parts of this rule to non-international armed conflicts is less clear than for international armed conflicts. The proposal to include the same rule as Article 35(3) of Additional Protocol I in Additional Protocol II was adopted by Committee III of the Diplomatic Conference leading to the adoption of the Additional Protocols in 1974, but rejected in 1977.
The reason for the change of mind is not clear but may have been linked to the simplification process undertaken in the last stages of negotiations in order to ensure the adoption of Additional Protocol II. This rule is contained in other instruments pertaining also to non-international armed conflicts.
This rule is included in military manuals which are applicable in or have been applied in non-international armed conflicts.
In addition, many States have adopted legislation criminalizing “ecocide” or the wilful infliction of “widespread, long-term and severe damage to the natural environment” in any armed conflict.
There are a few condemnations in relation to environmental damage caused in non-international armed conflicts.
Most official statements condemning environmental damage in armed conflict, however, are of a general nature and do not appear to be limited to international armed conflicts.
However, even if this rule is not yet customary, present trends towards further protection of the environment and towards establishing rules applicable in non-international armed conflicts mean that it is likely to become customary in due course. This is particularly true as major damage to the environment rarely respects international frontiers, and also because the causing of such damage may violate other rules that apply equally in international and non-international armed conflicts, for example the prohibition of indiscriminate attacks (see Rule 11).
The difference between this rule and the rule requiring the application to the environment of the general rules of international humanitarian law applicable to civilian objects (see Rule 43) is that this rule is absolute. If widespread, long-term and severe damage is inflicted, or the natural environment is used as a weapon, it is not relevant to inquire into whether this behaviour or result could be justified on the basis of military necessity or whether incidental damage was excessive. It was for this reason that the expression in Additional Protocol I “widespread, long-term and severe” sets such a high threshold. The three conditions are cumulative and the phrase “long-term” was understood by the adopting States to mean decades. The Committee Established to Review the NATO Bombing Campaign Against the Federal Republic of Yugoslavia stated in its final report in 2000 that the threshold was so high as to make it difficult to find a violation. The report indicated that for this reason there was disagreement as to whether the damage in the Gulf War crossed this threshold.
In its report to Congress in 1992, the US Department of Defense questioned whether the damage met the threshold of “long-term”.
“Ecocide” is defined in the penal codes of the countries of the former Soviet Union as “mass destruction of the flora and fauna and poisoning of the atmosphere or water resources, as well as other acts capable of causing an ecological catastrophe”.
Viet Nam’s Penal Code refers to “destroying the natural environment”.
As a violation of this rule inevitably presupposes that there can be knowledge or an inference that a certain method or means of warfare will or probably will cause widespread, long-term and severe damage to the environment, there will need to be some understanding of which types of warfare will have such disastrous consequences on which types of environment. If read together with Rule 44, this means that parties to a conflict are obliged to inform themselves as far as possible of the potential results of their planned actions and to refrain from actions that could may be expected to cause widespread, long-term and severe damage to the environment. In a report submitted in 1993 to the UN Secretary-General on the protection of the environment in time of armed conflict, the ICRC states:
It is not easy to know in advance exactly what the scope and duration of some environmentally damaging acts will be; and there is a need to limit as far as possible environmental damage even in cases where it is not certain to meet a strict interpretation of the criteria of “widespread, long-term and severe”.
Unlike Additional Protocol I, the ENMOD Convention does not contain a cumulative standard, and the expression “long-lasting” is defined in that Convention as “lasting for a period of months, or approximately a season”.
The difference was made because ENMOD refers to the deliberate manipulation of the environment, rather than to an intended or expected result on the environment. It is significant that, in 1992, the parties to the ENMOD Convention adopted an interpretation of the Convention that prohibits the use of herbicides if used for environmental modification and having the effect of upsetting the ecological balance of a region.
This interpretation was based on a desire by States parties not to limit the Convention to science-fiction-type weapons, and therefore reflects an interest in providing greater protection to the environment during armed conflict.