The anticipated implications of international environmental policy strategies are critical for the success or failure of international negotiations on climate change policies. In this paper, we discuss the complex modeling issues related to the incorporation of international environmental policy measures in one of the popular applied general equilibrium models for international trade, the so-called GTAP model. Special attention is paid to an extended version of this model addressing environmental and energy problems, viz. the GTAP-E model. Various numerical results of simulation experiments with this model at a worldwide scale will be presented. In particular, we will address the question how to include the frequently discussed instruments of International Emission Trading, Joint Implementation and Clean Development Mechanisms in a computable general equilibrium model such as the GTAP-E model. © 2005 Elsevier B.V. All rights reserved.