Assessing the impacts of ecological governance on carbon storage in an urban coal mining subsidence area

Abstract

Carbon storage, which is considered one of the important service functions of ecosystems, plays an irreplaceable role in maintaining the regional carbon balance and regulating the climate. Regional carbon storage is closely related to regional land use and land cover (LULC). With the development and expansion of coal resource-based cities, the construction areas of cities have started to overlap with underground coal resources. Coal mining leads to regional LULC changes, such as large-scale surface subsidence and subsidence waterlogging, and LULC has changed and consequently affected carbon storage in urban coal mining subsidence areas. This study analyses the change trend of carbon storage and clarifies the effect of ecological governance being implemented in the urban coal mining subsidence area. First, the LULC change map of the ecological governance scenario was obtained via remote sensing technology. Then, the natural evolution scenario from 2000 to 2021 was simulated using the hybrid cellular automata and Markov chain, also named the CA–Markov model. Finally, combined with the subsidence waterlogging in the urban subsidence area, the InVEST model was used to analyse the spatial–temporal variation characteristics of carbon storage. The analysis results showed that LULC and carbon storage in small-scale urban coal mining subsidence areas changed dramatically between 2000 and 2021 due to coal mining and ecological governance. The subsidence waterlogging area increased by 1033.83 ha, resulting in total carbon storage decreasing by 37,560.21 t. Subsidence waterlogging is the key influencing factor in the decrease in carbon storage. The forest area increased by 1270.83 ha, resulting in a total carbon storage increase of 216,531.04 t. Forest is the crucial increasing factor in carbon storage. The changes in carbon storage in the urban coal mining subsidence area can be classified as follows: obvious improvement area, basically unchanged area, and significantly degraded area. As opposed to the natural evolution scenario, the ecological governance scenario increased the coverage of the “obvious improvement area” by 818.46 ha in the urban coal mining subsidence area. Overall, this study illustrates that ecological governance can effectively improve carbon sequestration and is conducive to the healthy development of coal resource-based cities.