Uncertainties around reductions in China's coal use and CO2 emissions

Chinese coal consumption dropped 2.9% in 2014 according to preliminary official statistics(1) released in 2015. This was hailed as historic after China's meteoric growth in the 2000s(2). The International Energy Agency used it to estimate similar to 1.5% reduction in Chinese fossil CO2 emissions for 2014(3), and an unprecedented 0.2% reduction in global emissions(4). Similar preliminary coal consumption statistics are announced every year, and will be watched closely after China's recent slowdown in emissions growth and pledge to peak emissions in 2030 or earlier. However, Chinese energy statistics are frequently revised and often contain large anomalies(5,6), implying high uncertainty. For example, BP used different Chinese data to estimate a 0.9% increase in 2014 CO2 emissions(7,8). Here, we analyse these preliminary announcements, with an approach that can be used to assess the robustness of similar future announcements. We show that the preliminary 2.9% reduction in coal consumption is inappropriate for estimating CO2 emissions, that coal-derived energy consumption stayed flat but is likely to have decreased in 2015, and that Chinese fossil CO2 emissions probably increased similar to 0.8% in 2014. We also analyse recent revisions of official energy statistics, and find that they imply 925 MtCO(2) (11.2%) higher emissions for 2013, and 7.6 GtCO(2) (9.2%) higher total emissions for 2000-2013.