WARM Public Comment

On December 26, 2023, EPA opened a comment period on the Waste Reduction Model version 16 and its supporting documentation. The comment period is now closed.

We also released the final WARM Methodology External Peer Review report and the final WARM Data Quality Assessment report. These two final reports are not open for comment. We will use public comments received on WARM version 16 and its documentation, along with the final findings of the external peer review and data quality assessment to improve the usability, integrity, and functionality of WARM.

WARM provides high-level comparisons of potential greenhouse gas emissions, energy use and economic impacts when considering different materials management practices. Materials management practices include - source reduction, recycling, anaerobic digestion, combustion, composting and landfilling. Since its launch in 1998, EPA has updated WARM many times to expand its coverage of material types, management pathways, and impact indicators, while incorporating new and improved data in the model. EPA requested comment on the following questions: 

1. How can the scientific rigor and adherence to modeling best practices and assumptions in WARM regarding biogenic carbon emissions, carbon storage in forests, soils, and landfills, and utility offsets from combustion be improved?
2. How can WARM better align with best practices in climate change modeling and assumptions?
3. How can the alignment of data, assumptions, and model components in WARM with real market practices be improved?
4. In assessing WARM, how well do the modeled management practices represent the diversity of practices typically used in the United States?
5. When evaluating WARM, how accurately does it depict the common secondary use of recycled materials in the United States?
6. What recommendations can be made for enhancing the clarity, transparency, relevance, and usability of WARM and its accompanying documentation?
7. Are there any studies or data sources that are relevant to WARM but are currently not integrated, and how could their inclusion be beneficial for future development?
8. What are the potential advantages and disadvantages of conducting future WARM model development in a more publicly accessible development environment, such as GitHub, to encourage increased transparency and public involvement?
9. What are the potential advantages and disadvantages of EPA considering the use of readily available data from public sources (such as the Federal Life Cycle Assessment Commons) in WARM, especially the use of non-waste management data, to enhance data consistency, accessibility and reliability across federal government life cycle work?

EPA welcomed comments on WARM version 16 and its supporting documentation through docket number EPA-HQ-OLEM-2023-0451 in Regulations.gov.