Key findingsSuomeksiAerosol emissions from the European countries cause currently a negative top-of-the-atmosphere direct aerosol forcing (cooling effect). The forcing is largest in central Europe and extends to over Arctic. Compared with the present-day situation, currently agreed policies affecting air pollutant emissions will reduce the aerosol cooling effect (i.e. enhance warming) over both Europe and Arctic areas during the next couple of decades. Less future warming will be expected if emission reductions target emission sources with high share of black carbon. However, the warming will be enhanced even more if maximum technically feasible reductions of air pollutant emissions, especially sulfur dioxide, will be implemented. There is a significant reduction potential for black carbon emissions with technologies that are currently available. To reach the reductions, technology switch is required that is not substantially promoted by current emission legislation. It is not possible to reduce the emissions of black carbon alone. From the impact standpoint it is important to analyze the effects of emission reduction technologies and policies to multiple pollutants, i.e., organic carbon and sulfur emissions. Residential wood combustion is a major source of black carbon emissions in many countries, both in Europe and developing world. In addition to stove technology, user's behavior in the form of stove operation and fuel quality has substantial impact on residential wood combustion emissions. Information campaigns about proper stove operation can be used to influence user’s behavior. Black carbon emissions are at highest in winter and thus their effect on melting of snow and ice is pronounced. This was shown by the ground-based black carbon monitoring at background sites in Finland. The probable reason for this is residential wood combustion. The largest uncertainties in estimating the climatic effects of black carbon in Arctic areas arise from the difficulties in modeling the efficiency by which black carbon particles are transported from their source areas to the Arctic atmosphere, and in understanding how these particles interact with Arctic clouds. |
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