World Induced Technical Change Hybrid (WITCH) Model

WITCH is an integrated assessment model designed to assess climate change mitigation and adaptation policies. WITCH consists of a dynamic global model that integrates, in a unified framework, the most important elements of climate change. The economy is modeled through an intertemporal optimal growth model, which captures the long-term economic growth dynamics. A compact representation of the energy sector is fully integrated (hard linked) with the rest of the economy so that energy investments and resources are chosen optimally, together with the other macroeconomic variables. Land use–mitigation options are available through a soft link with a land use and forestry model (GLOBIOM). A climate model (MAGICC) is used to compute the future climate. Climate change impacts the economic output through a damage function, depending also on the rate of investments in adaptation, which allows the model to account for the complete dynamic of climate change mitigation and adaptation.

WITCH was developed and is maintained by the RFF-CMCC European Institute on Economics and the Environment.