Sustained methane emissions from China after 2012 despite declining coal production and rice-cultivated area

Abstract China's anthropogenic methane emissions are the largest of any country in the world. A recent study using atmospheric observations suggested that recent policies aimed at reducing emissions of methane due to coal production in China after 2010 had been largely ineffective. Here, based on a longer observational record and an updated modelling approach, we find that China's growth in methane emissions did decline (0.3±0.1 (±1σ) Tg CH4 yr-2 for 2012-2017, as compared to 0.77±0.2 Tg CH4 yr-2 for 2010-2012). We find that the decrease in growth rate after 2012 can in part be attributed to a decline in China's coal production. However, coal mine methane emissions have not declined as rapidly as production, implying that there may be substantial fugitive emissions from abandoned coal mines that have previously been overlooked. We also find that emissions over rice-growing regions do not show a negative trend (0.13±0.05 Tg CH4 yr-2 for 2010-2017) despite reports of shrinking rice paddy areas, implying potentially significant emissions from new aquaculture activities, which are thought to be primarily located on converted rice paddies.