RELEVANT INCIDENTAL HARM FOR THE PROPORTIONALITY PRINCIPLE
2. Reverberating effects 23
Reverberating effects is not a notion defined or expressly mentioned in IHL. It is usually understood in contrast to direct effects, and sometimes also referred to as indirect effects, cascading effects, repercussions, knock-on effects, or long-term consequences.
The issue of reverberating effects has gained prominence in the last few decades, in particu-lar since the 1991 Gulf War,24 and more recently in the debates on cyber warfare, where the interconnectivity of military and civilian computer systems increases the risks that the effects of an attack spread beyond the intended target.25 This heightened attention is due to the increased interconnectedness and interdependence of modern societies,26 to technological development in targeting capabilities,27 and to the development of more sophisticated col-lateral damage estimation tools. For example, the United States Colcol-lateral Damage Estimation
22 Philippine Army Soldier’s Handbook on Human Rights and International Humanitarian Law (2010), p.
57. See also Canada military manual and Norway statement, op. cit. The Final Report by the ICTY Com-mittee Established to Review the NATO Bombing Campaign against Yugoslavia also stated that ‘Even when targeting admittedly legitimate military objectives, there is a need to avoid excessive long-term damage to the economic infrastructure (…) with a consequential adverse effect on the civilian population.’ (ICTY, Final Report to the Prosecutor by the Committee Established to Review the NATO Bombing Campaign Against the Federal Republic of Yugoslavia, paragraph 18). According to Reynolds Jefferson: ‘[a] thorough indirect collateral damage assessment must evaluate all foreseeable effects of a military operation on violence, crime, political infrastructure, housing, environment, public health, water and sanitation infrastructure, power infrastructure, poverty, economy, labour and unemployment and education.’; “Collateral Damage on the 21st Century Battlefiel”, in: Air Force Law Review, Vol. 56, 2005, p. 90. For an example of incidental economic harm not considered as relevant see US DoD, Law of War Manual, 2015, paragraph 5.12.2.1.
23 For a detailed discussion of the issue, on which this section partly draws, see Isabel Robinson, “Pro-portionality and precautions in attack: the reverberating effects of the use of explosive weapons in populated areas”, in: International Review of the Red Cross (forthcoming).
24 See e.g. Françoise Hampson, “Means and Methods of warfare”, in: Peter Rowe (ed.), The Gulf War 1990-91 in International and English Law, London, Routledge and Sweet & Maxwell, 1993, pp. 97ff.
25 See e.g. Cordula Droege, “Get off my cloud: cyber warfare, international humanitarian law and the protection of civilian”, in: International Review of the Red Cross, Vol. 94, No. 886, summer 2012, p.
572ff.
26 ICRC, International Humanitarian Law and the Challenges of Contemporary Armed Conflicts, 03/IC/09, Report, 28th International Conference of the Red Cross and Red Crescent, 2-6 December 2003, p. 13.
27 Michael Schmitt, “The Principle of Discrimination in 21st Century Warfare”, in: Yale Human Rights and Development Law Journal, Vol. 2, No. 1, 1999, p. 168.
Methodology (CDM) explains that: ‘[a]s a science, the CDM uses a mix of empirical data, prob-ability, historical observations, and complex modelling for CDE [collateral damage estimation]
analysis’.28
First, it can be noted that the proportionality rule does not expressly restrict the relevant inci-dental harm to ‘direct’, contrary to the relevant military advantage.29 Despite some exceptions, it is today generally agreed in the literature that the incidental harm relevant for the rules on proportionality and precautions in attack is not limited to the direct effects of the attack, but include the reverberating or indirect ones. A number of military manuals or other official State documents on collateral damage or targeting make reference to this30 and it is also the position taken in the Tallinn Manual.31 For example, the United Kingdom 2004 military manual states that commanders must bear in mind ‘the foreseeable effects of attack’, and gives as an example an attack on a military fuel storage depot where there is a foreseeable risk of the burning fuel flowing into a civilian residential area causing injury to the civilian population.32 The Final Declaration of the Third Review Conference of States Parties to the CCW also noted that the ‘foreseeable effects’ of explosive remnants of war on civilian populations was a factor to be considered in applying the principle of proportionality and precautions.33
The question of reverberating effects is of particular importance for urban warfare, especially when explosive weapons with a wide impact area are used, as will be discussed in the last panel of this Colloquium. Beyond the mere buildings and roads, cities are an intricate web of interconnected infrastructure, in particular with regard to water and electricity. The use of explosive weapons against lawful targets in cities might incidentally damage an underground drinking water or sewage pipe, or an electricity line supplying the water treatment plant or a
28 US Chairman of the Joint Chiefs of Staff Instruction, No-Strike and the Collateral Damage Estima-tion Methodology, CJCSI 3160.01, 2009, p. D-1. In addiEstima-tion, the InstrucEstima-tion states: ‘The CDM is not an exact science. The supporting technical data and processes of the methodology are derived from physics-based computer models which generate statistical results, weapons test data, and operational combat observations’ (p. D-2).
29 See Robin Geiss, “The Conduct of Hostilities in Asymmetric Conflicts”, in: Journal of International Law of Peace and Armed Conflicts, Vol. 3, No. 23, 2010, pp. 122ff, p. 128.
30 See e.g. Australian Defence Force Publication 3.14 Targeting (2009), paragraph 1.21; USA, The Com-manders Handbook on the Law of Naval Operations NWP 1-14M, July 2007, paragraph 8.11.4;
31 Tallinn Manual, op. cit., p. 160, paragraph 6 on Rule 51. See also Sassoli/Cameron, op. cit., p. 65.
32 UK: The Joint Service Manual of the Law of Armed Conflict, JSP 383, 2004 (amended in 2013), para-graph 5.33.4.
33 Third Review Conference of the High Contracting Parties to the Convention on Prohibitions or Restric-tions on the Use of Certain Conventional Weapons Which May Be Deemed to Be Excessively Injurious or to Have Indiscriminate Effects, Final Declaration, 17 November 2006, preambular paragraph 11, CCW/
CONF.III/11 (Part II), p. 4.
hospital. This risks causing health problems to the civilian population and possibly increasing the mortality rate.34
It is obviously not possible to foresee all the effects of an attack. But the ICRC’s position is that foreseeable reverberating effects must be taken into consideration under the rules on proportionality and precautions.35 This is subject to a standard of reasonableness, as stated by the International Criminal Tribunal for the former Yugoslavia.36 However, there is no specific cut-off point in time or space beyond which the incidental effects would be irrelevant for the proportionality principles when they are reasonably expected. The 1974-77 Diplomatic Confer-ence indeed rejected attempts to limit the incidental loss to those in the immediate vicinity of the military objective.37 Obviously, the more indirect the effects are, the less reasonably expected they become, and some remote possible effects will not be considered reasonably expected. However, this is contextual – and it may change with the increase in knowledge or collateral damage estimation methodology and tools. The only relevant criteria in our view remains whether they can be reasonably expected.
A key related issue is the obligation of the parties to ‘do everything feasible to assess wheth-er the principle of proportionality will be respected’.38 As was discussed yesterday, ‘“Feasible precautions” are those precautions which are practicable or practically possible taking into account all circumstances ruling at the time, including humanitarian and military consider-ations’.39
Numerous States have expressed the view that military commanders and others responsible for planning, deciding upon or executing attacks necessarily have to reach decisions on
34 See ICRC, Urban services during protracted armed conflict: a call for a better approach to assisting af-fected people, Geneva, 2015, in particular p. 31ff available at: < https://www.icrc.org/eng/assets/
files/publications/icrc-002-4249.pdf>.
35 ICRC 2015 IHL Challenges report, op. cit., p. 52.
36 In Galić, the ICTY Trial Chamber held that ‘in determining whether an attack was proportionate it is necessary to examine whether a reasonably well-informed person in the circumstances of the actual perpetrator, making reasonable use of the information available to him or her, could have expected excessive civilian casualties to result from the attack.’ Prosecutor v. Galić IT-98-29-T, Judgement, 5 December 2003 paragraph 58. See also Final Report, op.cit., paragraph 50.
37 Michael Bothe, Karl Josef Partsch and Waldemar Solf, New Rules for Victims of Armed Conflicts, Commen-tary on the Two 1977 Protocols Additional to the Geneva Conventions of 1949, Leiden/Boston, Martinus Nijhoff Publishers, 2nd edn. 2013, paragraph 2.6.2 on Art. 57, p. 406.
38 ICRC Customary IHL Study, op. cit., Rule 18.
39 Protocol on Prohibitions or Restrictions on the Use of Mines, Booby-Traps and Other Devices (Protocol II), 1980, Art. 3(4); Protocol on Prohibitions or Restrictions on the Use of Incendiary Weapons (Pro-tocol III), 1980, Art. 1(5); Pro(Pro-tocol on Prohibitions or Restrictions on the Use of Mines, Booby-Traps and Other Devices as amended on 3 May 1996 (Protocol II to the 1980 CCW Convention), Art. 3(10).
the basis of their assessment of the information from all the sources which are available to them at the relevant time. Many military manuals also underline that the commander must obtain the best possible intelligence, including information on concentrations of civilian persons, important civilian objects, specifically protected objects, the natural environment and the civilian environment of military objectives.40 As rightly put by Boothby, when at-tacks in urban areas ‘may be expected to damage utilities on which the civilian population relies, an assessment should be made of how long it is likely that the relevant services will remain out of action and what damage, injury, and death civilians are likely to suffer during that period as a result’.41 One needs therefore not only to estimate the foreseeable damage as such, but also the capacity and time required to repair the damage and recover the service. The protracted nature of the conflict, the death or displacement of the technicians or lack of spare parts because of sanctions may mean that it is difficult to fully repair damaged civilian objects for many years. When services and infrastructure are already under stress because of the con-flict – think of war wounded in hospitals for example – to incidentally damage infrastructure delivering essential services can have a very serious impact on the civilian population.
In conclusion, let me underline that it is a positive development that more and more infor-mation is available about the incidental harm caused by attacks, through collateral damage assessments after a particular operation and through more in-depth studies after a conflict.
Collateral damage estimate methodology will continue to improve accordingly, which in turn will raise the bar of what will be considered as feasible in terms of assessing the potential excessiveness of the expected incidental harm. This is not to say that technology will remove the fog of war and that commanders will have a perfect grasp of all possible consequences of each operation. However, the ability to anticipate the reverberating effects of an opera-tion will continue to improve, and this will bear on what can be expected from a reasonable military commander.
40 ICRC, Customary IHL Study, op. cit., p. 54.
41 William Boothby, The Law of Targeting, Oxford, Oxford University Press, 2012, p. 414.