Open source integrated assessment models

Integrated assessment models (IAM) are used extensively to support IPCC assessment reports. Moreover, there is an increasing interest in the connections and overlaps between IAMs and energy system models.

As with energy system models, the IAM projects have been progressively adopting open source development.

This posting logs some of those changes. It is also wikipost so others can update and extend the information provided.

IAM Repository License Comment
GCAM GitHub ECL‑2.0 license is OSI approved
GLUCOSE GitHub Apache‑2.0 repo given is for OSeMOSYS base
IMAGE development team working towards open source 1
MESSAGEix GitHub Apache‑2.0
REMIND GitHub AGPL‑3.0‑or‑later  with addition permissions related to GAMS interpreter 
WHICH GitHub Apache‑2.0


  1. personal comment on 22 May 2023

The model names given in full, as per the above order:

  1. Global Change Analysis Model
  2. Global Least-cost user-friendly CLEWs Open-Source Exploratory model
  3. Integrated Model to Assess the Global Environment
  4. Model for Energy Supply Strategy Alternatives and their General Environmental Impact (where the “ix” refers to a particular modeling platform)
  5. REgional Model of INvestments and Development
  6. World Induced Technical Change Hybrid

These IAMs are often coupled to secondary models, which capture say land usage in more detail. I have not noted these related models here.

My thanks to Hun for providing some background and impetus.

The Global Least-cost user-friendly CLEWs Open-Source Exploratory model (GLUCOSE) model, publication here, CC-BY-4.0 licensed model data here, built on Apache 2.0 licensed OSeMOSYS

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