Spatiotemporal dynamics of land use/cover and its impacts on carbon stocks in a Nigerian savanna

Land use and land cover (LULC) change is a major driver of carbon loss in tropical savannas, where human activities accelerate vegetation clearance and soil degradation. This study quantified the impacts of LULC transitions on ecosystem carbon stocks in Wukari, Taraba State, Nigeria, between 2005 and 2025 using multi-temporal Landsat imagery, GIS, and field-based soil measurements. Six dominant LULC classes (dense vegetation, sparse vegetation, farmland, bare land, built-up areas, and water bodies) were mapped using Landsat scenes for 2005, 2015, and 2025. Ecosystem carbon stocks were assessed across four pools, with soil organic carbon (SOC) and bulk density derived from 87 composite soil samples. Dense vegetation declined by 31 % (166,878 ha to 113,863 ha), while farmland and built-up areas expanded by 68 % and 540 %, respectively. Total ecosystem carbon stock fell from 16.63 to 13.82 million Mg C representing a 16.9 % loss, with SOC showing the largest absolute decline (1.08 million Mg C), reflecting its high sensitivity to LULC change. To link ecological losses with economic valuation, we employed a framework coupling carbon accounting with Nigeria-specific Social Cost of Carbon (SCC), revealing an estimated economic loss of USD 362 million due to carbon depletion. These findings demonstrate that rapid LULC transitions drive both ecological degradation and economic loss, emphasizing the need to protect natural vegetation and promote agroecological practices such as agroforestry and cover cropping to restore carbon reservoirs and soil health. Future land-use planning should integrate carbon accounting as a strategic tool to mitigate climate risks and secure progress toward SDG 13 and SDG 15. • Farmland and urban expansion in Wukari LGA caused a 16.9 % decline in ecosystem carbon stocks from 2005 to 2025. • Transitions from dense vegetation caused ∼92 % of total losses, raising bulk density and reducing SOC. • Soil was the largest carbon pool but showed greatest absolute carbon loss, underscoring its vulnerability to LULC change. • Carbon depletion imposed an economic cost exceeding USD 362 million, reducing ecosystem services and resilience. • Agroforestry, cover cropping, and minimum tillage can reduce carbon losses and support SDGs 13 and 15.