Spatial-temporal characteristics and driving factors of city level CO2 emissions from road passenger transport in China

Global climate change driven by carbon dioxide (CO₂) emissions has brought great challenges to countries around the world. Road transport takes an important part in CO₂ emissions from transport sector. Although many studies have explored road transport CO₂ emissions, few studies focused on CO₂ emissions from both highway transport and urban road transport at city level. To address this gap, this study examines road passenger transport CO₂ emissions across 31 provincial-level divisions and 325 cities in China using a bottom-up method, and analyzes their spatial-temporal characteristics and driving factors. The results show that road passenger transport CO₂ emissions in China increased steadily from 2010 to 2023, with a compound annual growth rate of 9.20%. The overall spatial pattern is characterized by higher emissions in the eastern regions and lower emissions in the western regions. In addition, the city level CO₂ emissions have significant spatial-temporal heterogeneity and disparities in CO₂ emissions have narrowed over time. Globally driving factors analysis indicates the population size and economic development are key factors of CO₂ emissions. At the city level, the effects of population, economy, road infrastructure, and land use on CO₂ emissions exhibit spatial-temporal non-stationarity among cities, indicating dynamic changes in CO₂ emission driving mechanisms across different periods and spaces. This study provides critical insights for policymakers aiming to reduce road transport CO₂ emissions and achieve the objectives of carbon peaking and carbon neutrality.