Résumé
Contrasting the very limited scientific evidence on the forest dieback issue with the sudden adoption of policies on air pollution decided in the FRG (1983-84) and extended to the European Community (1985). we propose an interpretative framework for the real internalizationl process at work in what was tantamount to a social crisis for public opinion, the media and political actors. We conclude that open scientific controversies on some environmental issues (effects, causes, solutions) pave the way for some actors to use the issue for their own techno-industrial strategies quite alien to ecological constraints. In cases of very high uncertainties on impacts, it becomes impossible to apply conventional social cost-benefit analysis (SCBA) as an optimizing tool. We propose to develop economic analysis as a negotiation language and to give pride of place to the value of learning time and to the crucial role of technological pluralism as a condition for flexibility in the future.