Assessing carbon stock and sequestration potential under land use and land cover dynamics in the Upper Blue Nile River Basin, Ethiopia

Abstract

The rapid expansion of agricultural and pastoral lands into natural ecosystems accelerates terrestrial carbon loss and intensifies carbon emissions. This study quantifies carbon stock dynamics in Ethiopia’s Abbay Basin from 2000 to 2023, driven by land use and land cover (LULC) changes. The LULC was classified using a random forest classification approach from Landsat 7 (2000) and 8 (2015, 2023) imagery. Biomass carbon density data, encompassing both above- and below-ground carbon, were obtained from the Distributed Active Archive Center (DAAC), while soil organic carbon (SOC) (0–30 cm depth) was derived from World Soil Information System. Carbon stock changes were assessed using the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model. The results reveal substantial LULC changes: agricultural land expanded from 38.86% to 42.69%, urban areas increased from 0.37% to 3.11%, while shrublands and grasslands declined. These shifts dramatically reduced total carbon stock, from 32.1 million tons in 2015 to 15.3 million tons in 2023, primarily due to deforestation and agricultural conversion. The findings indicate the urgent need for integrated land management strategies that reconcile economic development with ecosystem conservation to maintain carbon stocks and mitigate climate change.