This Working Paper presents a summary description of the OECD ENV-Linkages General Equilibrium model. This model has been developed by the Environment Directorate of the OECD Secretariat in order to assess the economic impact of abating Greenhouse Gases using several different economic instruments. The paper is divided into two parts. The first provides a brief description to the structure of the ENV-Linkages model and of its main equations. The second section describes the calibration method, first to fit the model on base year data, and second to dynamically produce a baseline emissions projection.