Quantifying Carbon Sequestration across Nigeria’s Vegetation Belts Using Light-Use Efficiency Model

Abstract

Quantifying terrestrial carbon sequestration is critical for climate mitigation, ecosystem management, and national carbon accounting, particularly in data-sparse regions such as West Africa. This study assessed the spatiotemporal dynamics of carbon sequestration across Nigeria’s major vegetation belts between 2001 and 2025 using a Light-Use Efficiency (LUE) model integrated with remotely sensed vegetation and climatic datasets. Net Primary Productivity (NPP) was estimated from Fraction of Photosynthetically Active Radiation (FPAR), solar radiation, rainfall, temperature, soil moisture, and drought indices derived from the European Commission Joint Research Centre ASAP platform. Spatial aggregation, trend analysis, and Generalised Additive Models (GAMs) were employed to evaluate temporal variability and climatic controls. Results showed that Nigeria sequestered approximately 72.0 billion tonnes CO₂e during the study period, confirming its significance as a major terrestrial carbon sink in sub-Saharan Africa. The Guinea Savannah (24.3 billion tonnes CO₂e) and Sudan Savannah (19.4 billion tonnes CO₂e) contributed more than 60% of national sequestration because of their extensive spatial coverage, whereas rainforest and mangrove ecosystems exhibited the highest sequestration efficiency per unit area. Annual sequestration ranged from 2,566 to 3,179 million tonnes CO₂e yr⁻¹, with strong interannual variability linked to hydroclimatic conditions, particularly rainfall deficits and drought stress. GAM analysis further revealed nonlinear ecosystem responses to climatic variability. Woody biomass accounted for the largest proportion of stored carbon (45%), underscoring the importance of maintaining long-term vegetation structure. The findings highlight pronounced ecological heterogeneity in Nigeria’s carbon dynamics and emphasise the need for region-specific conservation, restoration, and climate adaptation strategies to strengthen national mitigation efforts and carbon-monitoring systems.