Integrated assessment models as a basis for air pollution negotiations

During the last decade the issue of integrated assessment has received attention both in the scientific literature and in the negotiation of international air pollution agreements. More than often this literature does not differentiate between the integrated assessment as a process and the development and use of models as a tool for calculating the potentials of various scenarios. This paper describes the difference between the process and the tool, and illustrates this using the negotiations leading to the Second Sulfur Protocol (June 1994, Oslo). The situation in Europe (with a highly visible interaction between science and policy) will be compared with the United States (where new legislation was passed before the integrated assessment was finished). Further, the role of integrated assessment models in these negotiations will be discussed with special attention for the interaction between model builders and model users. Lessons from the recent European experience will be drawn. These include lessons for future protocols on acidification, and combined ozone/acidification/eutrophicationprotocols. These lessons will deal with the scale of the problem, the scope of the integrated assessment models, the development of models in parallel with scientific development and the various modes of interaction with the policy community.