Policy - WITCH

Model Documentation - WITCH
Model scope and methods - WITCH Model concept, solver and details - WITCH Temporal dimension - WITCH Spatial dimension - WITCH Policy - WITCH Socio-economic drivers - WITCH Population - WITCH Economic activity - WITCH Macro-economy - WITCH Technological change - WITCH Energy - WITCH Energy resource endowments - WITCH Energy conversion - WITCH Electricity - WITCH Heat - WITCH Grid, pipelines and other infrastructure - WITCH Energy end-use - WITCH Transport - WITCH Residential and commercial sectors - WITCH Industrial sector - WITCH Other end-use - WITCH Energy demand - WITCH Technological change in energy - WITCH Land-use - WITCH Agriculture - WITCH Forestry - WITCH Land-use change - WITCH Emissions - WITCH GHGs - WITCH Pollutants and non-GHG forcing agents - WITCH Carbon dioxide removal (CDR) options - WITCH Climate - WITCH Modelling of climate indicators - WITCH Climate damages, temperature changes - WITCH Non-climate sustainability dimension - WITCH Air pollution and health - WITCH Water - WITCH Appendices - WITCH Mathematical model description - WITCH Data - WITCH References - WITCH
Corresponding documentation
AIM-Hub BLUES C3IAM DNE21+ GCAM GEM-E3 GRACE IFs IMACLIM IMAGE MESSAGE-GLOBIOM POLES PROMETHEUS REMIND-MAgPIE TIAM-UCL WITCH
Previous versions
Archive of WITCH version 4.8
Model information
Model link	https://www.witchmodel.org/ https://github.com/witch-team/witchmodel https://doc.witchmodel.org
Institution	European Institute on Economics and the Environment (RFF-CMCC EIEE), Italy, http://www.eiee.org.
Solution concept	General equilibrium (closed economy)
Solution method	Optimization
Anticipation

When no policy is applied, the model is running a business-as-usual (BAU) case, which serves as a reference case with which the results with policy are compared.

WITCH can handle several types of policies:

• Quantitative climate targets on global temperature, on radiative forcing, on atmospheric carbon concentration, on greenhouse gas emissions or on carbon budget. In these case additional constraints are imposed in the model. The resulting carbon mitigation cost can be obtained in terms of loss of consumption or GDP.
• Carbon taxes can be imposed directly in the model, by adding a cost on carbon emissions.
• A carbon market can be activated, with the possibility to allow an to trade of emission permits. The temporal dimension is also taken in to account with the possibility of "banking and borrowing" over time.
• Additional subsidies, taxes and penalty on energies sources can be introduced.

The model is calibrated for some predefined policies: "BAU", "stabilisation at 450ppm", "stabilisation at 535ppm", "radiative forcing target at 3.2 W/m2" and "radiative forcing target at 2.8 W/m2".