Mimi-PAGE, an open-source implementation of the PAGE09 integrated assessment model

Area of Science:

• Climate Change Economics
• Integrated Assessment Modeling
• Environmental Policy Analysis

Background:

• Integrated Assessment Models (IAMs) are crucial for evaluating greenhouse gas mitigation policies.
• Three IAMs inform the social cost of carbon dioxide (SCCO₂) used by governmental bodies in the US and Canada.
• PAGE09 is one of the key IAMs influencing current SCCO₂ estimates.

Purpose of the Study:

• To introduce Mimi-PAGE, an open-source implementation of the PAGE09 IAM in the Julia programming language.
• To ensure the new implementation adheres to best coding practices and is publicly accessible.
• To validate the accuracy and compare the performance of the new implementation against the original model.

Main Methods:

• Development of Mimi-PAGE using the Julia programming language and the Mimi modular modeling framework.
• Adherence to rigorous software development standards, including code reviews, automated testing, and documentation.
• Verification of model output against the original PAGE09 model and comparative runtime analysis.

Main Results:

• Successful creation of an open-source, modular implementation of the PAGE09 IAM (Mimi-PAGE).
• Demonstrated equivalence between Mimi-PAGE and the original PAGE09 model outputs.
• Quantified runtime performance differences between the Julia and original implementations.

Conclusions:

• Mimi-PAGE provides a transparent, accessible, and validated tool for IAM research and policy analysis.
• The open-source nature of Mimi-PAGE facilitates community engagement, inspection, and further development.
• This implementation supports more robust assessments of climate policies and the social cost of carbon.