Evaluating Climate Change Impacts and Solutions


WITCH is a global dynamic model integrating the interactions between the economy, the technological options, and climate change.

It is developed at the RFF-CMCC-EIEE European Institute on Economics and the Environment, based in Milan, Italy.


The WITCH model allows accounting for the complete dynamic of climate change mitigation and adaptation for dozens of macro-regions for the next 100 years. For a complete description of the model check out our Documentation, or if you want to see some applications of our model, browse through our our blog (Stream) here below or play with the Policy Simulator.


The model is open-source and can be freely used and modified. Collaborations and external contributions are welcome! 

The source code can be browsed and downloaded from our Github repository 

Latest news

Recent publications and results

Climate thresholds and heterogeneous regions: Implications for coalition formation

The threat of climate catastrophes has been shown to radically change optimal climate policy and prospects for international climate agreements. We characterize the strategic behavior in emissions mitigation and agreement[…]

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The role of the discount rate for emission pathways and negative emissions

The importance of the discount rate in cost-benefit analysis of long term problems, such as climate change, has been widely acknowledged. However, the choice of the discount rate is hardly[…]

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Solar radiation management in cooperative and non-cooperative settings

It’s considered as a new strategy to complement traditional climate policies, but without sufficiently strong institutions, there is a risk that some countries will unilaterally deploy climate engineering to the[…]

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