China's aircraft-related CO2 emissions: Decomposition analysis, decoupling status, and future trends

In order to explore the decoupling relationship and its influence factors between the growth of China's civil aviation sector and carbon emissions, as well as to forecast future CO2 emissions, the extended log-mean Divisia index model (LMDI), Tapio decoupling model and an emission prediction model were applied in this study. The results show the following. (1) Total carbon emissions fluctuate on an overall upward trend, but the level of oil consumption per revenue tonne-kilometers (RTK) shows a steady downward trend. (2) Among the four main factors, the "transportation amount growth" factor contributed most to CO2 emissions increases; followed by transport structure adjustment effects and alternative fuel effects. The "energy consumption intensity" factor plays a major role in inhibiting CO2 emissions. (3) The decoupling state of civil aviation predominantly stayed in a weak decoupling prior to 1988, expansive coupling and expansive negative decoupling during 1988-2000, and expansive coupling post-2000, which implies that the government should take comprehensive measures to reduce CO2 emissions. (4) Based on eight scenarios, China's civil aviation sector is predicted to be responsible for 0.13 Gt of CO2 emissions by 2020. Between 2020 and 2050, CO2 emissions may increase by a factor 1.6 to 3.9.