Climatic and socioeconomic conditions jointly drive the carbon emissions of the urban passenger transport sector

Because of the dramatic rise in vehicle holdings, 21% of global energy consumption and nearly a quarter of carbon emissions now come from the transportation sector. However, the carbon emissions of the urban passenger transport sector ( CEUPT ) in provincial regions across different climatic zones and the influence of climate conditions on the CEUPT remain ambiguous. Herein, the CEUPT values of 31 provinces in China are quantified by constructing a “bottom-up” calculation model. Then, we elucidate the mechanisms through which climate and socioeconomic conditions jointly influence CEUPT . China’s CEUPT amounted to 483.7 Mt CO2, with a carbon intensity of 0.108 kgCO2/km in 2019. Private cars and motorcycles are the primary sources of carbon emissions, accounting for 295.8 Mt CO2 (61.2%) and 105.66 Mt CO2 (21.9%), respectively. Climate conditions determine people’s initial choice of travel mode, whereas socioeconomic conditions enable people to choose their preferred mode of travel, leading to spatiotemporal variations in the CEUPT . These findings should serve as references for government departments in regions with diverse climates to more extensively consider climate and socioeconomic conditions when formulating energy-saving policies for the urban passenger transport sector, thereby developing more targeted strategies to control the CEUPT .