Exploring the effect of urban sprawl on carbon dioxide emissions: An urban sprawl model analysis from remotely sensed nighttime light data

The easily and effectively exploration of the effect of urban sprawl on carbon dioxide emissions (EUC) is highly important for developing a sustainable urban spatial structure and a low-carbon urban planning system in a country. However, the comprehensive understanding of EUC and its transmission factors remain inadequate because previous studies were mainly concentrated on a single city, stage, and region based on the statistical data and traditional optical remotely sensed images. Thus, taking 41 typical cities in Southwest China as examples, an urban sprawl (US) model was developed for quantifying US from remotely sensed nighttime light data. The degree of EUC were then verified in different city sizes, stages, and regions. The transmission factors of EUC were further evaluated. Results show that US can aggravate carbon dioxide emissions (CE), and the robust analysis further confirms the positive effect of US on CE. US in small cities has the strongest effect on CE, whereas that in medium cities has the weakest effect. In addition, EUC is greater in pre-stage (2000–2009) than that in post-stage (2010–2018). EUC in Guizhou, Yunnan, and Sichuan–Chongqing gradually decreases. The transmission factor results indicate that US can aggravate CE through the urban transport, construction industry, and urban heat island. It is suggested that more attention should be paid to US environmental problems with China's future urban development.