Fossil-Fuel and Food Systems Equally Dominate Anthropogenic Methane Emissions in China.

Understanding fossil-fuel/food production and consumption patterns is the first step toward reducing the climate impacts of associated methane (CH4) emissions but remains unclear in China. Here, based on the bottom-up method, whole-industrial-chain CH4 emission in China (CH4-CHINA) is developed to track CH4 emissions from production to use and finally to disposal. The estimated Chinese national CH4 emissions in 2020 are 39288.3 Gg (25,230.8-53,345.7 Gg), with 50.4 and 49.6% emissions generated from fossil-fuel and food systems, respectively. ∼130,000 point sources are included to achieve a highly resolved inventory of CH4 emissions, which account for ∼53.5% of the total anthropogenic CH4 emissions in 2020. Our estimate is 36% lower than the Chinese inventory reported to the UNFCCC and 40% lower than EDGAR v6.0, mainly driven by lower emissions from rice cultivation, waste management, and coal supply chain in this study. Based on the emission flow, we observe that previous studies ignored the emissions from natural gas vehicles and residential appliances, coke production, municipal solid waste predisposal, septic tanks, biogas digesters, and food sewage treatment, which totally contribute ∼12.4% of the national anthropogenic CH4 emissions. The results discussed in this study provide critical insights to design and formulate effective CH4 emission mitigation strategies.