¹ Institute for Environmental Studies, Cost and Benefits of the EIA Directive (2007) 12.

² Ibid, 13–14.

³ Ibid, 8.

⁴ Ibid, 9.

⁵ Ibid, 10.

⁶ 1992 Rio Declaration on Environment and Development, UN Doc. A/CONF.151/26 (vol. 1), 14 June 1992.

⁷ On the distinction between principles and rules in international environmental law see Daniel Bodansky, Jutta Brunnée and Ellen Hey, International Environmental Law (Oxford: Oxford University Press 2007) 429 et sqq. It is important to remark, however, that some scholars consider EIA as a legal requirement or an implementing measure (Alexandre Kiss and Dinah Shelton, Guide to International Environmental Law (Leiden: M. Nijhoff 2007) 113 et sqq).

⁸ Goals and principles of environmental impact assessment, UNEP Res. GC14/25, 14^th Sess. (1987).

⁹ Convention on Environmental Impact Assessment in a Transboundary Context, Espoo, 25 February 1991, in force 10 September 1997.

¹⁰ UNECE Protocol on Strategic Environmental Assessment to the Convention on Environmental Impact Assessment in a Transboundary Context, Kyiv, 21 May 2003, in force 10 July 2010.

¹¹ Convention on Biological Diversity, Nairobi, 22 May 1992, in force 29 December 1993, Art. 14.

¹² The Protocol on Environmental Protection to the Antarctic Treaty, Madrid, 4 October 1991, in force 14 January 1988, Art. 8.

¹³ International Law Commission, Prevention of Transboundary Harm from Hazardous Activities, 2001, Art. 7.

¹⁴ Gunnar Sander, “International Legal Obligations for Environmental Impact Assessment and Strategic Environmental Assessment in the Arctic Ocean” (2016) 31 International Journal of Marine and Coastal Law 88 et sqq.

¹⁵ Mariachiara Alberton, Public Participation in Environmental Decision-making in the EU and in China: the Case of Environmental Impact Assessment (Baden-Baden: Nomos 2014).

¹⁶ Jean-Roger Mercier, “The World Bank and Environmental Impact Assessment” in Kees Bastmeijer and Timo Koivurova (eds), Theory and Practice of Transboundary Environmental Impact Assessment (Leiden: Nijhoff 2008) 291 et sqq.

¹⁷ Ludwig Krämer, “Impact Assessment and Environmental Costs in EU Legislation” (2014) 11 Journal of European Environmental & Planning Law 201 et sqq.

¹⁸ Kees Bastmeijer and Ricardo Roura, “Environmental Impact Assessment in Antarctica” in Bastmeijer and Koivurova, supra note 16, 175 et sqq; Timo Koivurova, “Could the Espoo Convention become a Global Regime for Environmental Impact Assessment and Strategic Environmental Assessment?” in Robin Warner and Simon Marsden (eds), Transboundary Environmental Governance: Inland, Coastal and Marine Perspectives (Oxford: Ashgate 2012) 323 et sqq; Laura Pineschi, “The Duty of Environmental Impact Assessment in the First ITLOS Chamber’s Advisory Opinion: towards the Supremacy of the General Rule to protect and preserve the Marine Environment as a Common Value?” in Nerina Boschiero and others (eds), International Courts and the Development of International Law: Essays in Honour of Tullio Treves (The Hague: Asser Press 2013) 425 et sqq.

¹⁹ MA Fitzmaurice, “International protection of the environment” (2001) 293 Recueil des Cours de l’Académie de Droit International 280 et sqq.

²⁰ Request for an Examination of the Situation in Accordance with Paragraph 63 of the Court’s Judgment of 20 December 1974 in the Nuclear Tests (New Zealand v France) Case, 22 September 1995, Order (1995) ICJ Reports 288 et sqq. According to para. 63 of the judgment rendered in 1974, the same kind of conduct by France established the possibility for the applicant to request an examination of the situation if the basis of the judgment “were to be affected” (Nuclear Tests (New Zealand v France), Judgment, 20 December 1974, (1974) ICJ Reports 457 et sqq., at para. 63). This provision was relied upon by New Zealand following the resumption, on the part of France, of nuclear testing in the same region.

²¹ Convention for the Protection of the Natural Resources and Environment of the South Pacific Region, Noumea, 24 October 1986, in force 22 August 1990.

²² Request for an examination, supra note 20, at para. 35.

²³ Ibid, at para. 63.

²⁴ Ibid, Dissenting opinion of Judge Weeramantry, at 344.

²⁵ Ibid, at 345.

²⁶ Ibid.

²⁷ Ibid.

²⁸ Gabčikovo‐Nagymaros Project (Hungary/Slovakia), Judgment, 25 September 1997, (1997) ICJ Reports 1 et sqq, at 7. As is known, the case concerned the joint construction, by Hungary and the Czech Republic, of a system of locks. Hungary invoked the suspension of the Treaty binding the two States to carry out the activity on the basis of the environmental risks involved (at para. 37). See, among others, John Fitzmaurice, “The Ruling of the International Court of Justice in the Gabcikovo-Nagymaros Case: A Critical Analysis” (2000) 9 European Environmental Law Review 80 et sqq.

²⁹ Gabčikovo‐Nagymaros Project, Separate opinion of Judge Weeramantry, at p. 111.

³⁰ Ibid, at 113.

³¹ Ibid, at 112.

³² Pulp Mills on the River Uruguay (Argentina/Uruguay), Judgment, 20 April 2010, (2010) ICJ Reports 14 et sqq.

³³ Ibid, at paras. 22, 118.

³⁴ Ibid, at para. 83.

³⁵ Ibid, at para. 104.

³⁶ Certain Activities Carried out by Nicaragua in the Border Area (Costa Rica/Nicaragua), Judgment, 16 December 2015. The proceedings were joint with Certain Activities carried out by Nicaragua in the Border Area (Costa Rica v Nicaragua).

³⁷ Ibid, at para. 1.

³⁸ Ibid, at para. 9.

³⁹ Ibid, at para. 100.

⁴⁰ Ibid, at para. 146.

⁴¹ Ibid, at para. 104.

⁴² It is to be noted, however, that not all judges concur with this idea. It is the case, for example, that Judge Donoghue, in his separate opinion, states not to be confident that State practice and opinio juris support the existence of such a specific rule (ibid, Separate opinion of Judge Donoghue, at p. 4).

⁴³ As regards the relationship between these two categories of obligations, in the Pulp Mills case, parties posited different conceptions of such a link. Whereas, according to Uruguay, procedural obligations form a means to achieve the respect of substantive ones (Pulp Mills, supra note 32, at para. 73), according to Argentina, a breach of procedural obligations automatically entails a violation of substantive ones (ibid, at para. 72). The Court took an intermediate position in this respect, by arguing that a functional link exists between the two categories of obligations, which can in any event also be seen separately (ibid, at para. 79).

⁴⁴ Ibid, at para. 112.

⁴⁵ Ibid, at para. 119.

⁴⁶ Ibid, at para. 121.

⁴⁷ Emphasis added.

⁴⁸ Pulp Mills, supra note 32, at paras. 190, 203.

⁴⁹ Ibid, at para. 204.

⁵⁰ Pulp Mills, supra note 32, at para. 204.

⁵¹ Ibid, at para. 206.

⁵² Certain activities, supra note 36, at para. 104.

⁵³ According to the definition given by the Seabed Disputes Chamber of the International Tribunal for the Law of the Sea, the due diligence obligation is an obligation of conduct that aims to ensure the prevention of environmental harm. Such an obligation consists not only of the adoption of legislative and administrative measures, but also of undertaking efforts to ensure that private operators comply with these norms (Responsibilities and Obligations of States Sponsoring Persons and Entities with Respect to Activities in the Area, 1 February 2011, at paras. 110–111).

⁵⁴ The uncertainties relating to the definition of the obligation of due diligence clearly emerge in the separate opinions attached to the Certain Activities and Construction of a Road cases. According to Judge ad hoc Dugard, the duty of due diligence is a standard of conduct required to implement the principle of prevention, which, in turn, is implemented though a number of specific, independent obligations, which include the duty to carry out an EIA (Certain activities, supra, note 36, Separate opinion of Judge Dugard, at paras. 7–9). The autonomy of the obligation to undertake an EIA is instead opposed by Judge Owada, who states this obligation is one element in the “holistic process” that emanates from the obligation of States to use due diligence to avoid environmental harm, “rather than a separate and independent obligation standing on its own under general international law” (ibid, Separate opinion of Judge Owada, at para. 18). In the same sense, see also the opinion of Judge Donoghue, which defines due diligence as the “governing primary norm” (ibid, Separate opinion of Judge Donoghue, at para. 9). As has been underlined, Art. 12 of the Convention on the Law of the Non-navigational Uses of International Watercourses (New York, 21 May 1997, in force 17 August 2014) while imposing a notification duty on State parties, actually falls short of obliging them to conduct an EIA, which has to be included only if “available”. However, it has been suggested that the “due diligence” standard contained in the same Convention places States under an obligation to provide a certain level of information (Alistair Rieu-Clarke, “Notification and Consultation on Planned Measures Concerning International Watercourses: Learning Lessons from the Pulp Mills and Kishenganga Cases” in Ole Kristian Fauchald, David Hunter and Xi Wang (eds), Yearbook of International Environmental Law (Oxford: Oxford University Press) 102 et sqq., 109.

⁵⁵ Pulp Mills, supra note 32, at para. 205.

⁵⁶ Ibid, para. 205.

⁵⁷ Certain activities, supra note 36, at para. 104.

⁵⁸ Ibid, at para.10.

⁵⁹ Ibid.

⁶⁰ Pulp Mills, supra note 32, at para. 209.

⁶¹ Ibid, at para. 210.

⁶² Ibid, at para. 211.

⁶³ Certain activities, supra note 36, at para. 154.

⁶⁴ It is interesting to note how a similar problem arose in relation to the application of Art. 5.7 of the Agreement on Sanitary and Phytosanitary measures (SPS measures) (allowing Members to adopt a precautionary approach, and therefore to adopt trade-restrictive measures in the absence of scientific certainty) and the general obligation to ensure that SPS measures are based on a risk assessment contained in Art. 5.1 of the Agreement. In an attempt to clarify the relationship between the two provisions, the Appellate Body has affirmed that “Article 5.7 is concerned with situations where deficiencies in the body of scientific evidence do not allow a WTO Member to arrive at a sufficiently objective conclusion in relation to risk” and that the same provision, Art. 5.7 “contemplates situations where there is some evidentiary basis indicating the possible existence of a risk, but not enough to permit the performance of a risk assessment” (United States – Continued Suspension of Obligations in the EC – Hormones Dispute, Report of the Appellate Body, WT/DS320/AB/R, 16 October 2008, at paras. 677–678).

⁶⁵ Certain activities, supra note 36, Separate opinion of Judge Dugard, at para. 19.

⁶⁶ Ibid, at para. 104.

⁶⁷ See, for example, Art. 19 of the Rio Declaration (supra note 6), according to which “States shall provide prior and timely notification and relevant information to potentially affected States on activities that may have a significant adverse transboundary environmental effect and shall consult with those States at an early stage and in good faith”. See also Art. 15.2(b) of the Protocol on Environmental Protection to the Antarctic Treaty (supra note 12) and Article 14.1(c) and (d) of the Convention on Biological Diversity (supra note 11).

⁶⁸ Certain activities, supra note 36, Separate opinion of Judge Donoghue, at para. 21.

⁶⁹ Certain activities, supra note 36, at para. 168 where the Court established that: “the duty to notify and consult does not call for examination by the Court in the present case, since the Court has established that Costa Rica has not complied with its obligation under general international law to perform an environmental impact assessment prior to the construction of the road.”

⁷⁰ In this regard, see the separate opinion of Judge Donoghue, who excludes that the words of the Court can be read in terms of incorporating national legislation (ibid, Separate opinion of Judge Donoghue, at para. 15). Contra see the opinion of Judge Bhandari, according to whom this possibility is actually allowed, even if the scarcity of guidance from the Court and other sources of international law lead one to think that there are presently no minimum binding standards in this regard (ibid, Separate opinion of Judge Bhandari, at para. 29). An intermediate position is the one held by Judge Dugard, who, on the basis of the works carried out by the ILC, affirms that that same matters are inherent in the nature of an EIA and cannot, therefore, be left to national legislation (ibid, Separate opinion of Judge Dugard, at para. 18). In the sense that the content of the rule must be set by domestic law, see Pierre-Marie Dupuy and Jorge E Viñuales, International Environmental Law (Cambridge: Cambridge University Press 2015) 70.

⁷¹ Pulp Mills, supra note 32, at para. 206.

⁷² Ibid, at para. 210.

⁷³ Emphasis added.

⁷⁴ Certain activities, supra note 36, at para. 206. In this regard, the decision of the Court not to find a legal obligation to consult with the public has been defined as “surprising” in the light of the emphasis put by several modern treaties on this point (Cymie R Payne, “Pulp Mills on the River Uruguay” (2011) 105 AJIL 94 et sqq., at 100).

⁷⁵ Certain activities, supra note 36, Separate opinion of Judge Bhandari, at para. 33.

⁷⁶ Ibid, at para. 41.

⁷⁷ Ibid, at paras. 45–46.