Integrated Assessment Modeling in Canada: The Case of Acid Rain

In the past, environmental decision making has been based on analysis of policy options with respect to emission reduction, deposition or concentration of pollutants and the design of preventive strategies using disparate single-model and discipline results. It was impossible to obtain optimal solution to environmnetal problems because it is difficult to conduct a coherent, systematic and sound analysis of environmental problems using a single disciplinary model. Thus, a need arises for an integrated approach in environmental policy making. The trend in environmental management is a move from single pollutant/single-effect to multi-pollutant/multi-effect approach and to the inclusion of socioeconomic issues for the purposes of determining the interaction of the environment with the economy. Integrated assessment modeling (IAM) enables us to examine these kinds of issues by creating logical and scientific relationship between the functioning of various ecosystems and the manner in which they respond to external stimuli. Recognizing the crucial role that an integrative approach could play in the development of sound environmental decision making, Environment Canada and other government agencies have jointly participated in the development of IAM. Using data on emissions, depositions, source-receptor matrix, costs of emission abatement, models describing the functioning of aquatic and terrestrial ecosystems, IAM can be used to identify optimal emission reduction strategies that benefit both the economy and ecology. The purpose of this paper is to demonstrate how economic aspects of emission abatement can be incorporated into IAM using acid rain as a case. The present study compared findings of optimal abatement strategies when economic abatement costs are included and when they are not. The findings indicate that i) a strong long-term commitment is required to provide 100% proetction and allow the rejuvenation of acidified lakes, ii) major reductions in emissions of SO2 are still required from the USA, iii) inter-regional trading with the USA can play a major role in reducing emission of SO2 , and iv) polluters, as well as the society, would be better-off when emission abatement strategies incorporate abatement costs than when not. This is particularly important in ensuring the integration of the economy with environment, and the attainment of sustainable development.