To decarbonize the transport sector to attain China’s goals of carbon peaking before 2030 and carbon neutrality before 2060, the national and subnational governments in China are actively developing action plans for CO2 peaking before 2030 for key sectors, including transport.

It is crucial that subnational governments understand the current magnitude of their (particularly provincial) transport sector emissions, the historic trends, and the sources of emissions when developing contextualized transport decarbonization action plans; as the saying goes, “you can't improve what you don't measure.” However, like in many emerging economies, the lack of reliable statistical data and consistent emissions accounting methods causes subnational governments to hit roadblocks when developing transport emissions inventories and sectoral decarbonization road maps. For example, without reliable statistics and consistent emissions accounting methods in China, estimates of subnational transport CO2 emissions are uncertain and inconsistent. Therefore, it is challenging for provincial governments to evaluate the current magnitude of transport emissions, identify major emissions sources, and develop localized transport decarbonization plans. It is also difficult for national governments to understand and compare transport emissions across provinces.  

Our approach

This study uses the top-down emissions accounting method to quantify direct transport CO2 emissions for 30 Chinese provinces during 2012 and 2019. The estimated provincial emissions, emissions intensity in terms of gross domestic product (GDP), emissions per capita, sources of emissions, and driving forces of emissions growth are used to inform the development of tailored local transport decarbonization plans and to provide recommendations to improve the certainty of subnational transport emissions estimations. The top-down accounting method employs the apportioning ratios from the Guidelines on the Development of Provincial Carbon Emission Peak Action Plans (consultation version) (Ministry of Ecology and Environment 2021), which reclassifies a certain percentage of fuel consumption (from private cars, light-duty trucks, and some heavy-duty trucks) from the nontransport sectors to the transport sector. The input data are provincial energy balances (National Statistical Bureau 2013–2020) and localized carbon emissions factors. The possible causes of the uncertainty associated with provincial transport emissions estimations are also analyzed.

Policy implications

Based on estimates of transport CO2 emissions for 30 provinces between 2012 and 2019, this study reveals the following findings:

  • During 2012 and 2019, most of China’s provinces witnessed growing shares of transport CO2 emissions in the total provincial direct emissions, and the transport sector became an important source of CO2 emissions on the provincial level. For economically advanced provinces or provinces with large shares of tertiary industry, the transport sector rose to the top emissions source.
  • In 2019, the eastern region had the highest transport CO2 emissions, and the western and central regions witnessed the most rapid emissions growth. The top five provinces with the largest transport emissions were Guangdong, Jiangsu, Shandong, Liaoning, and Sichuan; together, they represented one-third of China’s transport CO2 emissions. On the other hand, the central and western provinces experiencing the most rapidly growing emissions were Guizhou, Qinghai, Hunan, and Hubei.
  • Provinces have different transport emissions breakdowns. In Shanghai and Beijing, domestic aviation was the largest source of transport emissions. In Guangdong, Zhejiang, and 12 other provinces (mainly eastern regions), passenger cars were the major contributor of transport emissions, whereas trucks were the primary contributor of transport emissions in the central and western regions.  
  • The driving forces behind transport CO2 emissions growth vary across regions. On the national level, increases in transport CO2 emissions were attributable to multiple factors, including economic and population growth,
  • economic structural shift, and urbanization. However, on the regional level, the growth in transport emissions in the central region was driven primarily by economic growth, whereas in the western and northeastern regions it was fueled by urbanization and population changes.
  • Although in most of the provinces, transport emissions intensity (in terms of GDP) had been declining, transport emissions per capita had increased rapidly.  The only exceptions were the central and western provinces: transport CO2 emissions per capita had increased rapidly, and transport CO2 emissions per unit of GDP also showed no signs of decreases.  

  • To help different provinces better quantify transport CO2 emissions and inform the development of transport decarbonization action plans, this study recommends the following actions:

  • The national government should create a standardized transport emissions accounting methodology for provincial transport emissions accounting, expanding the coverage of transport fuel consumption statistics, distinguishing among domestic and international transport fuel consumption, and mandating the quality assurance and quality control process. Official subnational transport emissions inventories should be required and updated annually from a base year.
  • For provinces where the transport sector has become the largest source of CO2 emissions, their action plans for CO2 peaking before 2030 should place greater emphasis on the transport sector. 
  • The national government should not only pay attention to the eastern provinces with the largest transport CO2 emissions but also provide resources and build capacities in the central and western provinces with the most rapid emissions growth.
  • Provincial governments should have differentiated treatments on transport sector decarbonization, based on sources of transport emissions and growth paces.