S.M. Miller, A.M. Michalak, R.G. Detmers, O.P. Hasekamp, L.M.P. Bruhwiler and S. Schwietzke
An important aspect of reducing greenhouse gas emissions is understanding how effective regulations and policies designed to reduce emissions actually are. In this study we use atmospheric observations of methane to look at trends in human-produced and natural methane emissions in Asia as well as perform a sectoral breakdown of emission trends for China and India. Despite regulations aimed at reducing methane emissions from coal mining, we found that China's coal sector emissions continue to grow at rates comparable to those before the new regulations were implemented. Investigating what sectors are producing large amounts of greenhouse gases and how those emissions change over time allows for better mitigation strategies to be implemented.
Figure: Emissions trends by sector. a, b show the estimated emissions trend by sector for China and India, respectively. The coal sector appears to be driving the trend in China. No clear trends are obvious for India. Note that all trends in this figure are driven by GOSAT observations, not by the EDGAR anthropogenic emissions inventory used in the inverse model; the inventory estimate is constant with time. The EDGAR inventory does not include uncertainty estimates for the sector-specific breakdown of emissions, and uncertainty estimates are therefore not included here.
Anthropogenic methane emissions from China are likely greater than in any other country in the world. The largest fraction of China’s anthropogenic emissions is attributable to coal mining, but these emissions may be changing; China enacted a suite of regulations for coal mine methane (CMM) drainage and utilization that came into full effect in 2010. Here, we use methane observations from the GOSAT satellite to evaluate recent trends in total anthropogenic and natural emissions from Asia with a particular focus on China. We find that emissions from China rose by 1.1 ± 0.4 Tg CH4 yr−1 from 2010 to 2015, culminating in total anthropogenic and natural emissions of 61.5 ± 2.7 Tg CH4 in 2015. The observed trend is consistent with pre-2010 trends and is largely attributable to coal mining. These results indicate that China’s CMM regulations have had no discernible impact on the continued increase in Chinese methane emissions.
Miller, S.M., A.M. Michalak, R.G. Detmers, O.P. Hasekamp, L.M.P. Bruhwiler, S. Schwietzke (2019) "China’s coal mine methane regulations have not curbed growing emissions," Nature Communications, 10 (303), doi:10.1038/s41467-018-07891.