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Experts from the University of California, Berkeley developed the free and open source tool with over a dozen country delegates and organizations

Berkeley, CA (09 December, 2025) — At last Friday’s Executive Committee of the Multilateral Fund for the Implementation of the Montreal Protocol, United Nations, the Multilateral Fund Secretariat and researchers at the University of California, Berkeley debuted an open source modeling tool that provides global policymakers with unprecedented analytical and computing power to reach environmental and climate goals. The Eric and Wendy Schmidt Center for Data Science & Environment (Schmidt DSE) co-designed the tool, dubbed Kigali Sim, in partnership with the United Nations, as well as numerous countries and supporting organizations. Watch an introductory video and brief simulation here.

“Kigali Sim improves global regulation of highly-potent greenhouse gases such as hydrofluorocarbons,” said Sam Pottinger, Senior Research Data Scientist at Schmidt DSE and lead developer of Kigali Sim. “The tool simulates possible outcomes of policy interventions with greater efficiency and ease than previously possible. Kigali Sim is designed for those without programming expertise to access advanced modeling techniques, including optional AI features, and can work in a web browser.”

In order to achieve environmental goals set by the United Nations’ Montreal Protocol, policymakers need more powerful analytical tools to assess consumption trends and evaluate policy interventions. The Montreal Protocol, signed in 1987, is the most successful global environmental treaty in history and is ratified by all UN member states. Historically, the agreement sidestepped a potential catastrophe with the ozone layer by regulating ozone-depleting substances and greenhouse gases. Since 2016 the treaty’s focus is to phase down the most detrimental greenhouse gases like hydrofluorocarbons (HFCs) in refrigeration, air-conditioning, and the food system. To date the UN’s Multilateral Fund has facilitated more than $4.3 billion to support developing nations (also known as “Article 5” countries) in reducing production and consumption of HCFs and ozone-depleting substances. 

Using conservative estimates, Kigali Sim could help a hypothetical, middle-income nation formulate policies that could reduce overall greenhouse gas emissions by about 5% by 2040. For context, this would be the equivalent of the US cutting half of all agriculture-related emissions.

The 5% estimated reduction would represent around 10% of that country’s target for emissions reductions under the Paris Agreement given past commitments, long term goals, and expected cooling pressures. These approximations do not factor in additional co-benefits from reductions, including a country’s transition to more sustainable energy usage, which will likely produce greater environmental benefits overall. 

Schmidt DSE and the Multilateral Fund Secretariat designed Kigali Sim in partnership with officials from UN member countries and supporting organizations tasked with environmental policy decisionmaking. The tool provides an easy-to-use interface, where users can enter country-level modeling data to analyze HFC consumption trends. They can compare policies under consideration to quickly simulate potential impacts on emissions, consumption, and equipment across multiple scenarios. Users can choose to bring in an AI assistant to more quickly process input data from various sources and formats, explore policy ideas with the computer as a partner, and rapidly analyze simulation results using simple language questions and answers. 

“Kigali Sim offers an exciting opportunity to use cutting-edge data science tools like AI to guide funding implementation under the Montreal Protocol,” said Balaji Natarajan,
Secretariat of the Multilateral Fund for the Implementation of the Montreal Protocol, United Nations Environment Programme. “This tool provided a depth of policy analysis in under three hours that would have previously taken me three days to produce.”

“With this new resource, we can make greater strides to preserve our global environment,” said Tina Birmpili, Chief Officer of the Multilateral Fund. “It’s a compelling example of how we can bridge the innovation brought by university research centers like Schmidt DSE with international policy making. » 
               
During the beta testing phase earlier this year, delegates and other experts from more than 12 countries actively used Kigali Sim and provided critical feedback for improvements. This community represented Article 5 nations, donor countries (which financially contribute to the Multilateral Fund), international nonprofits and agencies, and private consultants.                                                                                                     

Kigali Sim is free and open-source, and does not require previous coding experience. The tool can run locally in web browsers or on a desktop while allowing users to maintain privacy over their data. 

“Kigali Sim is incredibly unique in that it democratizes access to rigorous modeling techniques, and puts the latest in data science directly into the hands of decisionmakers,” said Douglas McCauley, Schmidt DSE Faculty Director & Associate Professor at the University of California, Berkeley. “Moreover, users with a variety of technical backgrounds can perform complex simulations and arrive quickly at results.”

Schmidt DSE leverages the power of modern data and environmental science to address pollution, the biodiversity extinction crisis, and other urgent climate change-caused challenges. This is the third open source policy tool that the team has developed to date; others include a model that predicts the global production, use, and fate of plastics through 2050, and a tool to help depict future corn yields in the US amidst a changing climate. Schmidt DSE is part of the College of Computing, Data Science, and Society and the Rausser College of Natural Resources at UC Berkeley.

About the Eric and Wendy Schmidt Center for Data Science & Environment at UC Berkeley: 
Schmidt DSE leverages the power of modern data and environmental science to create a healthy planet where people and nature can thrive. Launched in 2022, Schmidt DSE is a partnership between UC Berkeley’s Rausser College of Natural Resources and the College of Computing, Data Science, and Society, with the financial support of Eric and Wendy Schmidt. Read more about our work here.

About the Multilateral Fund: The Multilateral Fund spearheads global efforts under the Montreal Protocol, channeling funding, fostering collaboration, and upholding environmental stewardship in the pursuit of a sustainable future for all. Our mission is to support developing (Article 5) countries in eliminating ozone-depleting substances and greenhouse gases, bolstering climate resilience, bettering public health, and cultivating a healthier, more livable world.