Large emissions of greenhouse gases are expected to cause major environmental problems in the future. European policy makers have therefore declared that they aim to implement cost-efficient and fair policies to reduce carbon emissions. The purpose of this paper is to assess whether the cost of the EU policies for 2020 can be reduced through the inclusion of carbon sequestration as an abatement option while equity is also improved. The assessment is done by numerical calculations using a chance-constrained partial equilibrium model of the EU Emissions Trading Scheme and national effort-sharing targets, where forest sequestration is introduced as an uncertain abatement option. Fairness is evaluated by calculation of Gini-coefficients for six equity criteria to policy outcomes. The estimated Gini-coefficients range between 0.11 and 0.32 for the current policy, between 0.16 and 0.66 if sequestration is included and treated as certain, and between 0.19 and 0.38 when uncertainty about sequestration is taken into account and policy-makers wish to meet targets with at least 90 per cent probability. The results show that fairness is reduced when sequestration is included and that the impact is larger when sequestration is treated as certain.