Spatio-temporal characteristics of the relationship between carbon emissions and economic growth in China's transportation industry.

The economic and social development of a country rely heavily on transportation. In China, it has become the third largest energy consumption sector and generates substantial amounts of carbon emissions. In the present study, direct and indirect carbon emissions from the transportation industry throughout China's 30 provinces during 1997-2017 were calculated. Further, to reveal the spatio-temporal characteristics of the relationship between carbon emissions and economic growth, the standard deviational ellipse and Tapio decoupling method were employed. The main results are as follows. (1) The total carbon emissions from the transportation industry increased from 132.79 million tons (Mt) in 1997 to 849.64 Mt in 2017, with an average annual growth rate of 9.72%; direct carbon emissions accounted for approximately 86% of the total. (2) Carbon emissions as well as the added value of the transportation industry had the same spatial distribution characteristics, presenting a northeast-southwest pattern during 1997-2017. Although their spatial distribution patterns were mainly in the north-south direction, the development in the east-west direction became increasingly obvious. (3) The decoupling index in the transportation industry was greater than 0.8 for most years, with an expansive negative decoupling state or an expansive coupling state. The differences in carbon emissions and economic growth between various provinces showed a spatio-temporal disparity of the decoupling states in the transportation industry. The obtained results are of considerable interest for China's policymakers to set more reasonable carbon emission reduction goals and implement targeted policies according to the carbon emission situation at a local scale.