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MIMOSA 1.3.1

Status: released 21 July 2026

MIMOSA 1.3.1 makes model result names more consistent and easier to interpret. In particular, costs expressed as a fraction of GDP now use the unsuffixed name, while absolute costs in currency units use the suffix _abs. Global quantities consistently use the prefix global_.

The default configuration and model equations have not changed. However, this release renames a number of Pyomo components and CSV output rows, so existing analysis scripts and model extensions may need to be updated.

Highlights

  • Cost variables consistently distinguish fractions of GDP from absolute currency amounts.
  • Global variables consistently use global_ as a prefix.
  • Carbon-price, cumulative-emissions, emission-reduction and welfare names are harmonised.
  • Documentation, examples, calibration code and tests use the new result names.
  • The guide to variables, equations and constraints now explains index sets, equation functions, smooth helper functions and numerical-stability considerations in more detail.

Cost and transfer variables

For costs and financial transfers, the unsuffixed variable is expressed as a fraction of gross GDP. The corresponding _abs variable is expressed in the configured currency unit.

MIMOSA 1.3.0 MIMOSA 1.3.1 Meaning in 1.3.1
mitigation_costs mitigation_costs_abs Regional attributed mitigation costs in currency units
rel_mitigation_costs mitigation_costs Regional attributed mitigation costs as a fraction of gross GDP
domestic_mitigation_costs domestic_mitigation_costs_abs Regional physical mitigation costs in currency units
global_rel_mitigation_costs global_mitigation_costs Global mitigation costs as a fraction of global gross GDP
damage_relative_global global_damage_costs Global damage costs as a fraction of global gross GDP
avoided_damage_costs_global global_avoided_damage_costs Global avoided damage costs as a fraction of global gross GDP
financial_transfer financial_transfer_abs Regional financial transfer in currency units
rel_financial_transfer financial_transfer Regional financial transfer as a fraction of gross GDP

damage_costs and damage_costs_abs already followed this convention and retain their names.

Other renamed results

MIMOSA 1.3.0 MIMOSA 1.3.1
carbonprice carbon_price
global_carbonprice global_carbon_price
cumulative_global_baseline_emissions global_cumulative_baseline_emissions
cumulative_emissions global_cumulative_emissions
emission_relative_cumulative global_relative_cumulative_emissions
regional_emission_reduction regional_emission_reductions
yearly_welfare global_welfare

The model attributes cumulative_emissions_trapz and rel_mitigation_costs_min_level have similarly been renamed to global_cumulative_emissions_trapz and mitigation_costs_min_level.

Configuration compatibility

The corresponding configuration keys have not changed. Existing parameter dictionaries should continue to use:

params["emissions"]["cumulative_emissions_trapz"]
params["economics"]["MAC"]["rel_mitigation_costs_min_level"]

Only the names of the model components and exported result rows changed.

Updating analysis scripts

Code that selects rows from MIMOSA output must use the new names. For example, absolute mitigation costs are now selected with:

mitigation_costs = output.loc[output["Variable"] == "mitigation_costs_abs"]

For mitigation costs as a fraction of GDP, use:

mitigation_costs_relative = output.loc[output["Variable"] == "mitigation_costs"]

Model extensions that access renamed components directly must make the equivalent substitutions, for example m.cumulative_emissions[t] becomes m.global_cumulative_emissions[t].

Documentation improvements

The documentation for emission trading, financial transfers, effort sharing and welfare now follows the new naming convention. The extension guide also includes expanded explanations of:

  • the shared m.t and m.regions index sets;
  • how lambda functions are evaluated in regional and global equations;
  • the distinction between equations, general constraints and soft equalities;
  • soft_switch, soft_min and soft_max; and
  • choosing smooth approximations, bounds and constraints with appropriate numerical scales.