CO2 emission of urban passenger transportation in China from 2000 to 2014

This study reviewed the urban passenger transportation (UPT) development of seven typical cities in China from 2000 to 2014, estimated the UPT CO2 emission, analyzed the structure, and discussed the main factors of UPT CO2 emission. Results showed that increases of GDP, population, and UPT scale of the cities have speeded up. The most significant development of UPT is that the growth of private vehicles is greatly faster than that of public transportation. The total and per-capita UPT CO2 emissions both increased. The share of private vehicles emission to total UPT CO2 emission has increased, with the share in range of 65%-88% in 2014, exponentially leading to the increases of total and per-capita UPT CO2 emission. Although UPT CO2 emission structure with more share of public transportation would slow down the UPT CO2 emission increase, private vehicle CO2 emission is recognized as the dominated driving factor. Contributions of driving factors, such as GDP, population, private vehicle CO2 emissions, to UPT CO2 emission are different among the cities. Private vehicle CO2 emission is the dominated factor for UPT CO2 emission in Beijing and Taiyuan. Besides private vehicle CO2 emission, GDP also plays an important role in UPT CO2 emissions of Chengdu, Shanghai, Guangzhou, and Urumqi. Contributions of private vehicle CO2 emission and GDP to UPT CO2 emission are almost same in Xi'an.