Uncovering external drivers of methane emissions in China: A multi-perspective input-output analysis of key emission sources

As the world’s largest methane (CH4) emitter, China's efforts in CH4 mitigation are crucial for global climate action. Existing studies primarily focus on sector-specific internal mitigation from a production-side perspective, while understanding the external drivers of CH4 emissions from a consumption-side perspective is essential for developing effective mitigation strategies. This study establishes an integrated analytical framework combining the environmentally extended input-output (EEIO) model, structural path analysis (SPA), and structural decomposition analysis (SDA) to examine how external economic activities affect CH4 emissions from China's key emission sources (energy and agricultural activities) between 2002 and 2017 at sectoral, supply chain, and socioeconomic levels. Our findings reveal that most energy-CH4 emissions are induced by the final demand of the construction sector through indirect paths involving multiple intermediate steps. In contrast, agricultural-CH4 emissions are largely driven directly by final demand, while a significant proportion is also induced through indirect paths by the food & tobacco sector. Additionally, several key supply chain pathways are identified as major contributors to both energy-CH4 and agriculture-CH4 emissions. The SDA results highlight that the effects of capital formation, export, and urban household consumption are the main drivers of increased CH4 emissions, while the emission intensity effect and the production structure effect play a crucial role in mitigating emission growth. Moreover, the driving mechanisms exhibit significant variations across different time periods and emission sources, particularly in oil&gas-CH4 and livestock-CH4. These findings suggest that China needs to adopt a diversified policy mix that integrates sector-specific, supply chain-wide, and socioeconomic considerations to achieve more effective CH4 mitigation.