From emissions in Europe to critical load exceedances in Finland - uncertainty analysis of acidification integrated assessment

摘要

This paper evaluates the uncertainties in integrated assessment modeling of acidification, relates the findings to European emission reduction strategies and draws conclusions about further research priorities. The paper presents a mathematical and literature analysis of the uncertainties in the ecosystem areas at risk of acidification in finland inherent in the integrated assessment of air pollution used in the development of European emission abatement agreements. Owing to the need for relatively simple models, integrated assessment is uncertainty prone. Uncertainties in national inventories of acidifying emissions in European countries and their spatial locations, in the atmospheric transport of the pollutants and in the critical loads, characterizing the ecosystems' sensitivity, were taken into account. The relative contributions of the uncertainties in the individual modules of the integrated assessment modeling to the overall uncertainty of ecosystem protection levels were calculated for 1990 and 2010, assuming the implementation of the recent UN/ECE Gothenburg Protocol curbing long-range transboundary air pollution. The robustness of the acidification risk estimates was shown to improve significantly from 1990 to 2010, which is due to the anticipated large overall decrease in deposition levels. For most parts of Finland uncertainties in the critical loads were found to dominate the total uncertainty of integrated assessment modeling of acidification. Thus further research efforts to reduce uncertainties should be mainly focused on a more precise description of ecosystem processes. In Southern Finland and in areas close to Russian emission sources also the uncertainties in emission inventories and in the atmospheric transport and deposition modeling were shown to be significant, which emphasizes the need for high-resolution modeling when developing protection strategies for natural areas in the vicinity of significant emissions. Using a 95% confidence level, a probabilistic impact assessment of emission reduction alternatives indicates a considerably more pessimistic ecosystem protection level than the deterministic approach used in European decision-making.