Evidence of non-additional pig manure offset projects

Grayson Badgley , Freya Chay

Each carbon offset represents the claim that one ton of CO₂ emissions has been avoided or removed from the atmosphere. For offsets to deliver real climate benefits, the emission reductions they represent must be “additional,” meaning they would not have occurred without financial support from the carbon market. Despite its importance, additionality has proven difficult to achieve in practice. Prior research and investigative reporting have documented widespread non-additionality throughout the carbon market, yet quantitative assessments of additionality remain rare. Here, we use offset project documentation and government statistics to evaluate the financial additionality of pig manure management projects in China that capture and burn manure-derived methane. We find that 31 percent of the anticipated annual offset credits (5.95 million of 19.2 million) from the 74 projects we analyzed are likely non-additional because they ignore the financial benefits associated with generating energy from captured methane. Notably, our analysis relies only on project-reported data and publicly available government statistics, requiring no modeled counterfactuals. Our findings suggest that current market rules require significant reform to ensure that offsets represent real climate benefits.