4. The expanding scope of the law: global reach and international cooperation

These conceptual developments have not taken place in a vacuum, as they correspond to the actual evolution of the law and state practice.

A number of fundamental developments characterize the contemporary evolution of this body of law, and they have in turn contributed to the clarification of the extent and scope of the basic principle referred to above.

One development to note is that environmental law applies today not only to activities that cause transboundary effects between neighbouring states - as was very much the case at the time of the Trail Smelter,⁸ the Lake Lanoux,⁹ or the Gut Dam,¹⁰ but also to those that have effects at a long distance or, still more important, that have an effect upon areas beyond territorial jurisdiction. Thus the law has evolved from a purely national level in its origins to a transnational dimension and then to a properly international or global role. This geographical extension of the law, quietly developing during this century, has set the stage so that the current problems affecting the environment can be addressed.

The most significant breakthrough in this process of innovation came with the Trail Smelter decision in 1941.¹¹ Relying on principles and decisions of US courts and on the basis of identifying a general principle of international law, the arbitral tribunal concluded that "no state has the right to use or permit the use of its territory in such a manner as to cause injury by fumes in or to the territory of another or the properties or persons therein.... "¹² Such a principle meant in fact that international law had entered the field of transboundary environmental protection, albeit still limited to the territories of states. A somewhat similar conclusion was reached by the International Court of Justice in the Corfu Channel Case¹³ in relation to acts contrary to international law or the rights of other states. It should be noted, however, that in the specific domain of the utilization of rivers, a similar principle had been identified since the early part of the century.¹⁴

The Trail Smelter decision had other interesting impacts on the development of the law. First, the tribunal ordered the smelter to "refrain" from causing further damage, which involves a preventive measure to forestall harmful activities in the future. The tribunal then established a regime for the control of emissions, including technical improvements to the industry and the institutional mechanism of an ad-hoc commission of three scientists that had the power to adopt binding decisions.¹⁵

After these first steps were given specific applications, the basic principles could be found in different situations before national courts or international tribunals. Thus it was no surprise when the 1972 Stockholm Declaration included the often quoted Principle 21, which links states' sovereign rights relating to the exploitation of resources and national environmental policies to the "responsibility to ensure that activities within their jurisdiction or control do not cause damage to the environment of other States or of areas beyond the limits of national jurisdiction."¹⁶ The link had already been established under international law, which explains why there was general agreement to express it in this Principle.

Various international documents and treaties have since reaffirmed the essence of Principle 21 or further expanded it in order to cope with new situations affecting the environment. The case of the Cosmos 954,¹⁷ the EEC environmental policy adopted in 1973,¹⁸ the 1979 Convention on Long-Range Transboundary Air Pollution¹⁹ with its 1985 Protocol setting in place precise obligations for the reduction of sulphur emissions,²⁰ and the IAEA Conventions on Notification and Assistance in the case of Nuclear Accident²¹ are all cited as examples of the outreaching scope of environmental law today.²²

Principle 21 was a further step of the utmost importance because it extended the transboundary reach of the law to include areas beyond the limits of national jurisdiction, thereby improving upon the reach of the Trail Smelter decision and providing the global scale referred to above. This development has been particularly apparent in relation to the marine environment and the atmosphere. The regime established under the 1982 Convention on the Law of the Sea for the marine environment,²³ like the Convention on the Prohibition of Military or Any Other Hostile Use of Environmental Modification Techniques,²⁴ the Vienna Convention for the Protection of the Ozone Layer of 1985,²⁵ and its Montreal Protocol on Substances That Deplete the Ozone Layer of 1987²⁶ have all established broad international regimes based on the principle of responsibility. The special case of Antarctica will be discussed further below.

However, as commented upon by the Italian document referred to above, many of these developments lack precise rules on responsibility, primarily because of the difficulty in identifying a single source or establishing the causal link between conduct and damage. The traditional requirements of international law were not always well suited to meet the changing conditions of industrial activity that are at the heart of current environmental problems. However, international law has begun to respond to the new challenges, and recent international regimes have included a more elaborate set of secondary rules governing responsibility. In addition, as suggested by the Italian document, it is always possible to complement the existing treaties with protocols dealing with responsibility.²⁷

A second major development was prompted by the changing international reality. As the Restatement of the Law (Third) states, "it soon became obvious that unilateral action by states to control pollution was not sufficient, and that international cooperation and regulation to protect the environment were necessary."²⁸ Here again the legal measures evolved from the national to the binational level, then to the regional ambit, and most recently to the global level, thereby setting the appropriate stage for dealing with current issues.

As a consequence of increased international cooperation to protect the environment, new obligations have devolved upon states in the environmental field. Some examples of how these obligations have broadened the scope of the basic principle of responsibility for environmental damage are: (1) the responsibility to control activities taking place beyond the state territory - like the jurisdictional outreach provided for under IMO²⁹ and the Law of the Sea Conventions;³⁰ (2) the responsibility engaging the state for activities of private entities; (3) the need to obtain the consent of other states for given activities, as provided for under the Convention on the Control of Transboundary Movements of Hazardous Waste and Their Disposal;³¹ and (4) the more general obligation to notify and consult in environmental matters.³²

In the light of the present debate about whether treaties are an adequate source of rules of international law as to ensure the protection of the global environment, or whether more flexible procedures should be sought, it is worth remembering that treaties are not the only source of law to consider. Some of the major developments in the Law of State Responsibility in an environmental context have emerged from the operation of customary law and general principles of law as understood by international tribunals and the writings of eminent authors. In addition, the fundamental principle embodied in the maxim sic utere tuo ut alienum non laedas (use your own property so as not to injure the property of another)³³ has repeatedly been applied to the settlement of environmental disputes, on both national and international levels, and has formed the basis of the rationale inspiring the Trail Smelter decision, the work of the International Law Commission, and most of the international regimes in force for the protection of the environment. In fact, the very principle of international responsibility for environmental damage is an expression of this older general principle of law. Because the flexible use of the sources of international law has not historically been a problem, it should not really be a contemporary one either.