Developed countries should find cost-effective ways to decrease Green House Gas (GHG) emissions to comply with their Kyoto Protocol targets by year 2012. The target can be achieved either by domestic emission reduction or by buying quotas in international markets. Policy makers have to choose between these policy options and decide to what extend and when to use them. In democratic countries these choices may be constrained by limited information and misperception among voters and politicians. Bias in the decisions may occur because the choice of policy is complicated by dynamics and uncertainty. To explore the possibility of misperceptions we perform a laboratory experiment where subjects are asked to make this difficult policy decision during 12 years preceding 2012. Biases in the implementation of the policies were found.