摘要：Since the late 1990s, the Yangtze River Delta (YRD) has experienced profound growth in economic scales and urban size. However, it is still unclear how much energy is consumed from both fossil fuel and electricity usage for transportation sectors (TCO<sub>2</sub>). We take 10 sampled cities in the YRD as examples and examine their city-level sustainable levels from 1990 to 2018. Then, we observed that SHSN (Shanghai, Suzhou, Nanjing) are in leading positions, followed by WCN (Wuxi, Changzhou, Ningbo) and NXH (Nantong, Xuzhou, Hefei). We found that the cumulative TCO<sub>2</sub> in SHSN from 1990 to 2018 is the highest among groups, which is mainly due to the earlier industrialization in history. In 2018, SHSN had the highest TCO<sub>2</sub> (623.9 × 10<sup>4</sup> t), WCN was 311.9 × 10<sup>4</sup> t, and NXH was 166.4 × 10<sup>4</sup> t. TCO<sub>2</sub> per capita in SHSN reached its minimal (≈0.12 t) in 2018 among 29 years, while WCN and NXH shared the same levels (≈0.07 t). This could be attributed to the dense population and a series of low carbon policies announced in SHSN and WCN. NXH is still in the stage of high demands on economic-centered development. The primary source for TCO<sub>2</sub> in the YRD is fossil fuels. The TCO<sub>2</sub> contributed by transportation electricity usage is continually increasing, especially after 2010. This phenomenon represents that electricity can be a significant part of the YRD’s transportation sectors’ energy consumption shortly. A complex estimation model uncovers the complexity between the economy, environment, and carbon emissions in the YRD, which indicated that the decrease of TCO<sub>2</sub> in YRD could not be regulated solely by economic or environmental interventions. This study highlighted the urgency for socio-economic adjustments from carbonized to decarbonized structures in the YRD.
