World Induced Technical Change Hybrid (WITCH) Model

World Induced Technical Change Hybrid (WITCH) Model is a software model designed to assist in the study of the socio-economic dimensions of climate change and to help policy makers understand the economic consequences of climate policies. The model that incorporates a hybrid top-down optimization structure with a detailed bottom-up energy sector input component. The model can track all of the actions which impact the level of mitigation—such as R&D expenditures, investment in carbon-free technologies and adaptation, purchases of emission permits, or expenditures for carbon taxes—and thus allows for the evaluation of the equilibrium responses stimulated by different climate policy tools.