Methane emissions of energy activities in China 1980–2007

As the largest CH4 emitter, China produces CH4 at an increasing rate, especially from its energy activities. Presented in this paper is a detailed inventory and analysis of CH4 emissions from energy activities in China from 1980 to 2007 covering all the significant sources. The total energy-related CH4 emissions in China tripled during the period with an average annual increase rate of 4.7% and reached 21,943.1 Gg in 2007, 2.4 times of that in USA. As the largest emission source, coal mining increased its share from 69.2% (4559.5 Gg) in 1980 to 85.8% (18,825.5 Gg) in 2007; The second biggest source was fuel combustion, mainly bio-fuel combustion (2370.3 Gg in 2007); Oil and natural gas system leakage was a minor source but at a rapidly increasing rate. This transient emission structure is quite different from the steady structure of USA, which is dominated by the fugitive emissions from natural gas and oil systems. According to the lower IPCC Global Warming Potential, the annual energy-related CH4 emissions were equivalent to 9.1%–11.7% of China′s energy-related CO2 emissions, amounting to 548.6 Mt CO2-eq in 2007 which is greater than the nationwide gross CO2 emissions in many developed countries.