ENVIRONMENTALLY TARGETED OBJECTIVES FOR REDUCING ACIDIFICATION IN EUROPE

Integrated assessment modelling has been employed as a tool for derivi ng cost-effective strategies based on critical loads for the reduction of acidifying pollutants in Europe. Current negotiations towards a se cond European Sulphur Protocol, coordinated by the United Nations Econ omic Commission for Europe, have identified the need for additional de position targets as an intermediate step to achieving critical loads. Different applications of integrated modelling techniques are describe d, with particular emphasis on the definition of intermediate targets. These may be fixed externally to the model, or may be variable and in corporated within the optimization model. A dynamic approach to deposi tion targeting was shown to offer the greatest level of overall enviro nmental protection for a given cost. However, differences between the various targeted approaches are small relative to the alternative of f ollowing an untargeted approach, a result which illustrates the flexib ility of integrated assessment modelling as a useful policy tool.