Abstract: With the implementation of ecological projects such as “Returning Farmland to Forest and Grassland”, vegetation on the Loess Plateau has been restored, with positive consequence on the supply capacity of carbon sequestration services. However, whether the spatial distribution of this capacity matches the actual human demand remains unclear. Based on multi-source data such as land use and socio-economic data from 2000 to 2020, we used the InVEST model and population density method to quantitatively assess the supply and demand characteristics of ecosystem carbon sequestration services in northern Shaanxi, and used GeoDa to reveal their spatial matching cha-racteristics. The results showed that over the past 20 years, the area of grasslands and forests had steadily increased (by 2% and 1.6%, respectively), while cultivated land and unused land had continuously decreased (by 4.2% and 0.6%, respectively), and construction land had rapidly expanded (more than three times). The land use transition was mainly from cultivated land to ecological land (forest and grassland), and from grassland to construction land. The supply and demand of carbon sequestration services both showed upward trends, with a respective increase of 7.96×10⁶ and 34.92×10⁶ t. Spatially, the high-value areas of carbon supply were mainly distributed in the south part, while the low-value areas were mainly in the northwest part. The high-value areas of carbon demand were mainly distributed in the urban areas and showed a trend of spreading to the surrounding areas over time. Over the past 20 years, the supply and demand of carbon sequestration services were unbalanced, with the surplus area decreasing by 0.7%, and the spatial mismatch was obvious. The high-value surplus was mainly distributed in forests and grasslands, while the high-value deficit was mainly in construction land with intense human activities. Both the supply and demand of carbon sequestration services showed significant spatial aggregation characteristics. The Moran's I index of carbon supply and carbon demand fluctuated slightly, ranging from 0.431 to 0.448 and 0.780 to 0.813, respectively. The Moran's I index of supply-demand ratio gradually increased, ranging from 0.448 to 0.728. Our results could provide theoretical support for in-depth understanding of the evolution mechanism of the supply and demand of regional carbon sequestration service under the influence of ecological projects, as well as for the formulation of differentiated ecological regulation strategies.

Key words: carbon supply and demand, ecosystem service, spatial autocorrelation, northern Shaanxi