Life cycle greenhouse gas emission of pork production in China: Carbon inequality embodied in supply chain

Understanding feed formulation impacts and regional carbon transfer is crucial for sustainable pork supply chains. Currently, secondary greenhouse gas (GHG) emissions in the pork supply chain are often overlooked, and regional carbon transfer inequality impedes food sustainability. This study combines spatial equilibrium modeling with life cycle assessment to quantify China's 2021 pork supply emissions. Increasing pig feed crude fiber from 4 % to 10 % raised annual lifecycle GHG emissions from 275.7 to 300.8 Mt CO2eq, driven by 45 % and 13 % emission increases in farming and transportation, respectively. Additionally, carbon transfer among provinces is imbalanced, primarily flowing from southern pig farming regions to northern agricultural provinces. Hunan, Guangdong, and Jiangxi were the top three benefiting provinces, accounting for nearly 27.5 % of the total carbon transfer. Emission burden shifts through interprovincial transfers undermine reduction targets, necessitating strategies like integrating transfer responsibilities into carbon quota systems or compensation mechanisms to ensure equitable mitigation.