China's regional CH₄ emissions: Characteristics, interregional transfer and mitigation policies

Highlights: • China's CH₄ emissions have significant contributions to global climate change. • The total CH₄ emissions in 2010 amount to 44.3 Tg, half from energy activities. • Half of the national total direct emissions are embodied in interregional trade. • 2/3 of the embodied emission transfers via domestic trade are energy-related. • A national comprehensive action plan to reduce CH₄ emissions should be designed. - Abstract: Methane (CH₄), the second largest greenhouse gas emitted in China, hasn't been given enough attention in the country's policies and actions for addressing climate change. This paper aims to perform a bottom-up estimation and multi-regional input–output analysis for China's anthropogenic CH₄ emissions from both production-based and consumption-based insights. As the world's largest CH₄ emitter, China's total anthropogenic CH₄ emissions in 2010 are estimated at 44.3 Tg and correspond to 1507.9 Mt CO₂-eq by the lower global warming potential factor of 34. Energy activities as the largest contributor hold about half of the national total emissions, mainly from coal mining. Inherent economic driving factors covering consumption, investment and international exports play an important role in determining regional CH₄ emission inventories. Interregional transfers of embodied emissions via domestic trade are equivalent to half of the national total emissions from domestic production, of which two thirds are energy-related embodied emissions. Most central and western regions as net interregional CH₄ exporters such as Shanxi and Inner Mongolia have higher direct emissions, while the eastern coastal regions as net interregional importers such as Guangdong and Jiangsu always have larger embodied emissions. Since China's CH₄ emissions have significant contributions to global climate change, a national comprehensive action plan to reduce CH₄ emissions should be designed by considering supply-side and demand-side emission characteristics, mitigation potentials and emission responsibilities.