Social Cost of Carbon Computing Platform: Models from the Interagency Working Group

RFF's free, open-source computing platform allows users to access, run, and modify the social cost of carbon (SCC) models used by the federal Interagency Working Group to estimate the SCC.


Feb. 10, 2021


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In its establishment of estimates of the social cost of carbon for use across the federal government, the Interagency Working Group on the Social Cost of Greenhouse Gases (IWG) utilized three integrated assessment models from the peer-reviewed literature. The IWG harmonized the inputs of the models by employing a consistent set of assumptions about future socioeconomic conditions and climate parameters. These estimates and the underlying methods are publicly documented and have been subject to multiple rounds of review by analysts, stakeholders, and the courts. The source code is available for the IWG's full suite of models, however running them has historically been complicated due to the disparate programming languages used by the three models and their reliance on proprietary software packages.

To address these obstacles and improve the transparency and the accessibility of the IWG models, RFF has released the free and open-source MimiIWG software package. This package, for the first time, allows users to easily access, run, and modify all of the model versions and specific configurations utilized by the IWG in its 2016 estimates on a common and fully open-source software platform.

  • The MimiIWG software package is available here and documentation is available here.
  • A video tutorial explaining how to install and run the MimiIWG and supporting packages is available here and embedded below.
  • For technical assistance related to MimiIWG, please visit the Mimi Framework's user forum.

About the MimiIWG Software Package

The MimiIWG software package uses and demonstrates the capabilities of the Mimi.jl software package for creating, running, and performing analyses on Integrated Assessment Models. Mimi.jl provides an easy-to-use interface for defining components and building models in a modularized, transparent way. It is implemented in the Julia programming language, which is computationally fast while maintaining accessible syntax and conventions for novice programmers.

RFF, working with a team of researchers at UC Berkeley led by David Anthoff, has developed and released Mimi.jl in response to a core recommendation from the National Academies of Sciences (NAS) report for improving the Social Cost of Carbon to create an open source computing platform to improve the transparency of the estimates and foster collaboration among the climate impacts modeling community.

Many additional integrated assessment models and climate components beyond those contained in the MimiIWG package are available using the Mimi framework. For more information, please visit the home page for the Mimi Framework at


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