Comparative evaluation of multi-scale spatiotemporal variability and drivers of carbon storage: An empirical study from 369 cities, China

Under the background of global climate change, the role of carbon storage in mitigating the increase of atmospheric CO2 concentrations is of paramount importance. However, land use and land cover change (LULC) resulting from urban sprawl disturbs the level and distribution of carbon storage. This study aims to explore the spatiotemporal variability of carbon storage and the correlations between that and urban development for China's 369 cities in 2000, 2010, and 2020. The InVEST model and several multiple linear regression models are employed and the results show that: (1) Cities in western China sequester a large amount of carbon (maximum greater than 2000 TgC) and only some of them, from 2010 to 2020, can maintain a positive change in carbon storage. The rest of China shows a negative change, but a higher carbon storage per area (maximum greater than 0.01 TgC/km2 in the east). Moran's I shows that such variability has a significant spatial autocorrelation. (2) The intensification of the population, the growth of economy, and urbanization are the main factors influencing carbon storage, which are not only reflected on the national scale but also have different local characteristics in different regions. Cities in China's inland regions (e.g., western, some central, and northeastern China), most of which are developing cities, show more diversified impacts of their urban development on carbon storage. However, in developed cities, mostly concentrated in the eastern region, such impacts and variations show a more unified trend. Considering that environmental policy is often a national action, therefore, to strengthen the carbon sequestration capacity of cities, it is necessary to formulate not only a unified leading policy from the national level but also the practical policies of local governments of cities that match their development stages.