The climatic change is a matter of grave concern to the whole world. As a countermeasure against the climatic change convention, the Korean government has authorized the sale of diesel passenger cars since 2005. In this paper, we analyze the effects of the sales authorization of diesel passenger cars in its role as a countermeasure. Their share, carbon emissions, and pollutant emissions of each type of passenger car are analyzed using system dynamics. The result is that the carbon emissions are decreased by 5.4% but the pollutant emissions are increased by 5%. If the pollutant emissions are controlled, the sales authorization of diesel passenger cars would be a good countermeasure against the climatic change convention. (C) 2009 Elsevier Ltd. All rights reserved.