 uncertainty: we never know the whole truth and, in addition, at every moment new factors can appear, so that scientists must always be prepared to revise their position. However, such considerations must not prevent the adoption of legal rules. If we had waited for unanimous approval by all the scientists in the world before adopting safety regulations for nuclear activities, today there would by practically no such rules in this field. At a certain moment decision makers must make up their mind: their action will be strongly influenced by the awareness that the public may have of the problem. Thus, the process is a complex one composed of different sequences: facts - scientific findings- knowledge -awareness - decision-making, and the formulation of legal rules.
Taking into account these considerations, we may speak of a global challenge for international law. In the process that has been represented, we arrive now at the last stages, at least as far as certain aspects of global change are concerned: In some cases some legal rules already exist2 and must be further developed; in others, decisions still must be taken and translated into international legal rules.3 Anyway, even by now it can be useful to ask the question, what are the implications of global change on the international legal system, and what developments may be expected for the coming decades?
It is submitted that global change modifies the functions of the international legal system. Legal rules must be drafted in new fields, using new methods; existing rules must be implemented, sometimes by unusual means. Thus, new developments in the exercise of these functions are to be examined. However, such changes may also have an impact on the very structures of the international system. Reflections on the different aspects of such implications will form the second part of the present study.
The impact of global change on different functions in international law
In all legal systems different functions have to be fulfilled: legislation, execution, and control over the interpretation and the implementation of rules. One of the main characteristics - and one of the causes of the shortcomings - of international law is that although these functions exist, there are no corresponding organs that would ensure them on a generally obligatory basis. Law-making is still an occasional operation, based on the will of states; there is no executive power in the international field and international jurisdiction can only function with the consent of the concerned governments. Thus, modifications in the functions of international law may have a different scope than in the national legal systems.
Two aspects of such modifications due to global change seem to be of particular significance: the modifications in the law-making process on one side, and those in the implementation of rules on the other.
A. Implications of global change for the law-making process
The most dramatic change that occurred in international relations in the second half of the century was the expansion of the realm of international legal rules. These now cover large fields that formerly either fell into the exclusive jurisdiction of states, or did not exist at all as a matter for legal regulation. Examples are numerous in both categories. One may mention for the first field the protection of human rights, the improvement of labour conditions, health care, in addition to a number of economic activities; while for the second field one immediately thinks of the development of poor countries, the control of the production, trade, and use of drugs, the fight against terrorism and, of course, the protection of the environment.
It must be noted that in all these fields bilateral cooperation, which has been the general rule for international law, now only plays a secondary role: most actions need a multilateral approach. It seems that this fact is not sufficiently well understood. Environmental protection is a good example. At the end of the 1960s and the beginning of the 1970s, when growing environmental awareness h