We present a model for climate change policy analysis which accounts for the possibility that technology evolves endogenously and that technical change can be induced by environmental policy measures. Both the output production technology and the emission–output ratio depend upon a stock of knowledge, which accumulates through R&D activities. Two versions of this model are studied, one with endogenous technical change but exogenous environmental technical change and the other with both endogenous and induced technical change. A third version also captures technological spillover effects. As an application, the model is simulated allowing for trade of pollution permits as specified in the Kyoto Protocol and assessing the implications in terms of cost efficiency, economic growth and R&D efforts of the three different specifications of technical change.