Carbon dioxide (CO₂) emission, responsible for more than 60% of green house effects, was proved to be the leading contributing factor for global warming. China, which has been experiencing a remarkable growth of gross domestic product (GDP), has surpassed the United States and became the largest CO₂ emitter, sharing 24.2% of the world's total amount. Therefore, it is important to develop a reliable city-level CO₂ emission inventory for making viable CO₂ mitigation polices.

    Dr. CHEN Xiuzhi from South China Botanical Garden together with Dr. Su Yongxian from Guangzhou Institute of Geography et al. (2014) developed a normalized approach for assessing China's city-level CO₂ emissions of energy consumptions using DMSP/OLS nighttime light imageries and explored major driving forces for proposing feasible mitigation policies.

    China's CO₂ emission process was always consistent with its economic development and was classified into two rapid periods (1999–2002 and 2007–2010) and two slow periods (1992–1999 and 2002–2007). Most cities in Western, Central and Northern China belonged to the slow growth type, while most cities in Eastern China belonged to the rapid growth type. Cities with huge CO₂ emissions mainly congregated in southern and eastern coastal areas. Contrarily, cities with small amount of CO₂ emissions were mainly located in southwestern inlands. The CO₂ emission per capita (PCCE) in Northeastern and Eastern China was higher than that of Western and Central China. While the CO₂ emission per GDP (PGCE) of Northeastern and Western China was higher than that of Eastern and Central China. GDP increment was the major factor determining the carbon-emission growth rate, while industry structures and energy efficiencies were the major factors influencing regional CO₂ emission intensities.

   Therefore, in order to decrease the growth rate of China's CO₂ emissions but not hinder its economic development, major efforts should be focused on optimizing the industrial structures in Eastern and Central China where industries mainly belonged to technology- intensive, labor-intensive and light industry types, and guiding companies to increase the energy efficiencies in Northeastern and Western China, where industries mainly belonged to heavy and energy-related types. In particular, more attention should be paid to prevent the CO₂ emissions per energy consumption (PECE) of underdeveloped cities or provinces from increasing rapidly rather than only focusing on reducing the PECE of developed regions.

Reference: 

Su, Y., Chen, X.(co-first author), Li, Y., et al. (2014). China׳ s 19-year city-level carbon emissions of energy consumptions, driving forces and regionalized mitigation guidelines. Renewable and Sustainable Energy Reviews, 35, 231-243.