Diagrama de Caso de Uso general del Sistema

Precaution and proportionality are key components, not only of the precautionary principle but also under IHL. However, these concepts are not entirely interchangeable under the precautionary principle and IHL.

Proportionality arises under the precautionary principle when considering the course of action for addressing the threat of harm that has arisen.176 Proportionality seeks to ensure that responses to threats of harm ‘correspond to the perceived dimen- sions of the risk involved’.177 In other words, ‘[t] he more significant or the more serious the expected environmental impact, the more rigorous preventive or abatement meas- ures may, respectively must be’.178 Should there be more than one option available and uncertainty or doubt as to which should be chosen, in keeping with the precautionary principle the option which errs on the side of protecting the environment should be selected.179

Under IHL proportionality is the ‘requirement to select the method or means of attack likely to cause the least collateral damage or incidental injury, all other things

173 ibid.

174 Iron Rhine Railway (Belgium v Netherlands) (2005) 27 RIAA 35 (Permanent Court of Arbitration), [58]. 175 Trouwborst (n 112) 16. 176 ibid. 149– 58; De Sadeleer (n 120) 155.

being equal, relative to the military advantage obtained’.180 Proportionality under the precautionary principle is similar to proportionality under IHL in that it serves to ‘[adjust] the means to the objective’ and demands that ‘a course of action is chosen that corresponds to the size of the risk involved’.181 Where it differs is in the objective that is sought. Under the precautionary principle, actors are seeking to balance the desired action, usually development, with environmental protection. In this process ‘the pre- cautionary principle posits a presumption in favour of protection of the environment and public health’.182 In IHL, the consideration of proportionality results in weighing and balancing military necessity and humanity with the benefit of the doubt generally given to military actors.183 Critically, the draft principles on protection of the environ- ment in relation to armed conflict provisionally accepted by the ILC in 2015 include recognition of the requirement to consider the environment in the application of the principle of proportionality in IHL.184

Precaution also differs in its precise meaning. While precaution under IHL with- out question ‘constitute[s] obligatory standards of conduct’185 and is enshrined in cus- tomary international law,186 the concept ‘remains relatively abstract’,187 perhaps even more so than under the precautionary principle. Whereas the precautionary principle includes thresholds such as ‘serious or irreversible harm’ and ‘reasonable grounds for concern’, precaution in IHL is merely phrased as ‘all feasible precautions’. This is worri- some because it largely leaves it to the military decision- maker to determine what the requirements for fulfilling this duty will be. It fails to provide a yardstick by which to gauge whether the duty has been fulfilled. General principles of international law, such as intergenerational equity and the precautionary principle, can and should be used to provide more of a yardstick in IHL.

Whereas scientific uncertainty triggers the precautionary principle, the duty to take precautions in IHL flows from the principle of distinction. The duty of precaution in IHL includes things such as a ‘duty to verify the nature of the target’,188 an ‘obligation to choose the military objective that involves the least danger to civilian lives and civil- ian objects’,189 and an ‘obligation to give advance warning of an attack that may affect the civilian population’.190 As ILC Special Rapporteur Marie Jacobsson has stated, ‘If the environmental effects of a particular activity are known, then the measures taken 180 Michael N Schmitt, ‘The Principle of Discrimination in 21st Century Warfare’ (1999) 2 Yale Human Rights & Development Law Journal 143, 150.

181 Trouwborst (n 112) 149– 58. 182 De Sadeleer (n 120) 203.

183 Richard A Falk, Revitalizing International Law (Ames, IA: Iowa State University Press, 1989), 168. This can also be inferred from the remark in Gary D Solis, The Law of Armed Conflict:  International Humanitarian Law in War (Cambridge:  Cambridge University Press, 2010) 263 which states ‘Military necessity trumps the modest health risks to civilians [in the context of depleted uranium weapons].’ It can also be inferred from the decision of the ICTY Prosecutor, Carla Del Ponte, not to open a criminal inves- tigation into NATO bombings in Kosovo, ‘Prosecutor’s Report on the NATO Bombing Campaign’ 13 June 2000, The Hague, at <http:// www.icty.org/ sid/ 7846> accessed 31 May 2017.

184 Report of the ILC 2015 (n 89) Draft principle II- 2 and II- 3.

185 Jean- François Quéguiner, ‘Precaution Under The Law Governing The Conduct Of Hostilities’ (2006) 88(864) International Review of the Red Cross 793, 794.

186 Jean- Marie Henckaerts and Louise Doswald- Beck, ‘Rule 22. Principle of Precautions Against the Effects of Attacks’ in Customary Humanitarian Law Vol I: Rules (Cambridge: ICRC and Cambridge University Press, 2009).

to avoid them are preventative only; if the effects are unknown, then the same meas- ure can be labelled as precautionary.’191 While Jacobsson notes this in the context of the environmental distinction between prevention and precaution, I believe that this distinction would be usefully applied in the IHL context. The nature of the obligations said to flow from precaution in IHL would seem to suggest it has more of a preventive than precautionary nature, as precaution is understood in the IEL context, since the IHL precaution provisions appear to target commonsense risks to civilians which do not attract a high degree of uncertainty. For instance, providing a warning in advance to clear an area of civilians or attacking at night when fewer civilians are out or in the area. If civilians are unaware of a pending attack they cannot take measures to protect themselves. Likewise, if an attack is conducted during the day there are likely to be more civilians in the streets, in office buildings, etc. Issuing a warning and/ or attacking at night would simply seem to be commonsense preventive measures, rather than pre- cautionary in the sense of the precautionary principle.

Meanwhile, the precautionary principle has thresholds which trigger action and is closely linked to science even if uncertainty plays a large role. Fundamentally, where precaution in IHL seems to demand certain actions/ outcomes, ‘[a] fundamental fea- ture of the precautionary principle is that it is not concerned with guaranteeing a par- ticular outcome, but rather with the process by which a decision is made’.192

While precaution and proportionality in IHL and under the precautionary princi- ple both seek to protect entities from damage, under the precautionary principle they appear to provide better protection. Both seek to balance the size of the threat with the response to the harm, but under IHL the benefit of the doubt is often given to the mili- tary actor carrying out the risky activity. Meanwhile, under the precautionary principle the benefit of the doubt lies in favour of protecting the environment. Furthermore, the precautionary principle provides more substantive content and guidelines for assess- ing precaution (threat of serious or irreversible harm and scientific uncertainty) while under IHL a general and vague duty to take ‘all feasible precautions’ is given with lit- tle guidance as to the content of that duty. The precautionary principle provides more detailed and more protective standards than precaution and proportionality under IHL.