Gabčíkovo -Nagymaros Project (Hungary v Slovakia)

Gabčíkovo -Nagymaros Project (HungarylSlovakia), Judgment, I.C.J. Reports 1997, p. 7 

This contentious procedure arose out of a bilateral treaty, signed by Hungary and Slovakia in 1977, ‘Concerning the Construction and Operation of the Gabčíkovo –Nagymaros System of Locks’ (at Gabčíkovo in Slovakia and Nagymaros in Hungary), a ‘joint investment’ intended to produce hydroelectricity, improve navigation on the Danube River and protect against flooding. Additionally, Hungary and Slovakia undertook to ensure that the quality of water in the Danube was not impaired as a result of the Project and that compliance with the obligations for the protection of nature would be observed. Work on the Project began in 1978. In May 1989, as a result of the criticism that the project received in Hungary (relating to economic and environmental considerations in particular), the Hungarian government suspended the works at Nagymaros, finally abandoning the works in October 1989. Following that, Czechoslovakia took unilateral measures, intending to put Gabčíkovo into operation, by creating a diversion of the Danube, in its ‘Variant C’.

Hungary claimed that a state of ecological necessity existed in 1989, which precluded the wrongfulness of its decision to suspend and terminate work on the Project in contravention of the 1977 Treaty. The Court noted that Hungary’s concern for its natural environment amounted to an ‘essential interest’ within the meaning of Article 33 Draft Articles on the Responsibility of States for Internationally Wrongful Acts. It noted that Hungary had expressed uncertainties about the ecological impact of the project and had insisted on new scientific studies to be carried out. Nevertheless, the Court concluded that Hungary had neither established that these uncertainties amounted to ‘perils’ to the environment, nor that they were imminent, so that the condition of ‘grave and imminent peril’ for the establishment of necessity as a ground for precluding wrongfulness had not been satisfied. Having declined the plea of necessity, the ICJ held that Hungary had not been entitled to suspend and subsequently abandon works on the Project.

The ICJ went on to find that because Czechoslovakia had taken a unilateral measure to put Gabčíkovo into operation in its ‘Variant C’, it had also violated its obligations under the 1977 Treaty. It noted moreover that, while Hungary had violated its obligations under the 1977 Treaty, it had not forfeited its basic right to an equitable and reasonable sharing of the resources of an international watercourse. It quoted an excerpt from the Permanent Court of International Justice’s Judgment in the River Oder, which had defined the principle of ‘community of interest’, ‘the essential features of which are the perfect equality of all riparian States in the user of the whole course of the river and the exclusion of any preferential privilege of any one riparian State in relation to the others’ (PCIJ 1929, Series A, No. 23, p. 27), and extended that principle to non-navigational uses of international watercourses, referring also to the Convention on the Law of the Non-Navigational Uses of International Watercourses.

Hungary additionally advanced a number of reasons to support its claim that it had been entitled to terminate the 1977 Treaty by its notification of termination in 1992, one reason being that ‘new requirements of international law for the protection of the environment precluded performance of the Treaty’. Under Articles 15, 19 and 20 of the 1977 Treaty, Hungary and Slovakia were required to take such new requirements into account in order to ensure that the quality of water in the Danube was not impaired and that nature was protected. The ICJ recognised this, and noted that ‘both Parties agree on the need to take environmental concerns seriously and to take the required precautionary measures’ but expressed that they would also have to agree on the implications of their findings about new environmental norms and risks for the Project.

Before pronouncing on the legal consequences of its judgment, the ICJ noted that the Project’s impact upon, and implications for, the environment is considerable and that ‘in the field of environmental protection, vigilance and prevention are required on account of the often irreversible character of damage to the environment’.

The Court went on to pronounce for the first time, on the ‘concept’ of sustainable development, giving moreover an indication of what that concept entails (Note that Judge Weeramantry, in his Separate Opinion, argues that sustainable development is a principle of customary international law having an erga omnes character). The Court expressed that the concept entails reconciling economic development (such as the Project at issue) with protection of the environment (i.e. the principle of integration). Moreover, it noted that the concept of sustainable development involves assessing the impact of certain projects on the environment prior to initiating a project (i.e. carrying out an environmental impact assessment) and that, because environmental norms and standards must be taken into consideration and given proper weight also during the operational stage of a project, the duty to assess environmental impacts is a continuous monitoring obligation. Finally, it stated that the parties involved in a project are under an obligation to negotiate and to reach a solution that is to their mutual satisfaction, taking into account relevant sources of international environmental law, including the law of international watercourses. Notably, the Court was aloof in its use of terminology and it was only possible to deduce these procedural conditions from the manner in which the Court applied the ‘concept’ of sustainable development to the case at hand. The Court, in summing up the legal consequences of its judgment, noted that re-establishing the joint regime would also ensure that the concept of common utilisation of shared resources is satisfied (art 5(2) Convention on the Law of the Non-Navigational Uses of International Watercourses).