Chinese researchers have developed a comprehensive inventory of methane emissions and found that human activity is the largest contributor. 

Methane is one of the most important greenhouse gases in the world. Effective control of atmospheric methane concentration can remarkably slow the rate of global warming. 

The observed atmospheric methane concentration has grown rapidly in recent years, said the research, showing marked spatial-temporal variation. 

The existing inventories, most of which are yearly, provincial and incomplete, have failed to reflect the spatial variation and seasonal trends of methane emissions. 

Researchers from the Aerospace Information Research Institute, Chinese Academy of Sciences (CAS), aimed to develop a high-resolution monthly inventory of methane emissions across China in 2015 from eight major natural and anthropogenic sources. 

They found that the annual methane emissions across China were 61.65 teragram (Tg), of which 85 percent was associated with anthropogenic emissions. 

Energy activities, livestock, and paddy fields were the largest contributors, accounting for more than 70 percent of the total methane emissions, followed by vegetation, wetlands, wastewater, municipal solid waste and biomass burning. 

The researchers noted that the paddy fields, vegetation and wetlands emitted the most methane in summer and least in winter. 

The inventory of methane emissions is expected to improve people's understanding on the spatial-temporal variation of methane concentration in the atmosphere, said Shi Yusheng, an associate professor with the CAS, as well as formulating regional-seasonal-specific emission reduction policies. (Xinhua)