Spatiotemporal Change and Prediction of Carbon Storage in Nanjing Ecosystem Based on PLUS Model and InVEST Model

Change of land use has important impacts on change of carbon storage in terrestrial ecosystems. Studying the spatial layout of land use change and carbon storage can benefit the optimization of territorial space layout and the coordination of relationships between ecological protection and land development and utilization. Based on the land use data of Nanjing from 2000 to 2020, the changes of land use and carbon storage in Nanjing in the 20 years were analyzed using InVEST model, and the carbon storage distributions of Nanjing in 2040 were predicted using PLUS model for different development scenarios. The results show that: (1) Land use change had direct effects on the carbon storage in Nanjing. From 2000 to 2020, the urban construction land increased by 65.62% while the farmland, forest land and grassland reduced; and the carbon storage reduced by 2.62 × 10⁶ t. (2) By 2040, the predicted carbon storage will decline by 2.44 × 10⁵, 1.56 × 10⁶, 1.78 × 10⁶ and 1.62 × 10⁶ t in the scenarios of farmland protection, ecological protection, urban development and natural development, respectively. These predictions indicate that the policies of farmland protection and ecological protection can effectively control the reduction of carbon storage. (3) The spatial distribution of carbon storage was consistent with that of land use distribution. Areas with high carbon storage generally had less construction land and more ecological land. These results suggest that to improve the regional carbon storage level and achieve the goal of carbon neutrality, farmland and ecological land should be protected while construction land expansion should be restricted in the territorial planning in future.