Understanding China's agricultural non‑carbon-dioxide greenhouse gas emissions: Subnational insights and global trade dynamics

Methane (CH4) and nitrous oxide (N2O) are the second and third most important greenhouse gases after carbon dioxide (CO2), with 60% and 40% of global CH4 and N2O emissions coming from agriculture, respectively. However, the global nexus of non‑carbon-dioxide greenhouse gas (NCGHG) emissions at the subnational scale in China, the world's largest producer and consumer of agricultural products, remains under-examined. To fill this gap, we nested China's provincial input-output data with global data to clarify China's subnational-scale agricultural NCGHG emissions and connected global trade-based relationships. We found that China's production- and consumption-based agricultural NCGHG emissions in 2017 constituted ∼11% and ∼ 13% of the global agricultural NCGHG emissions, respectively, and that there existed a significant spatial mismatch between production- and consumption-based agricultural NCGHG emissions. Domestic consumption drove 94% of China's agricultural NCGHG emissions, which were dominated by China's domestic supply chains related to cattle farming and rice planting. We consequently propose to reduce agricultural NCGHG emissions by improving the efficiency of critical supply chains and agricultural waste utilization.