Carbon Sequestration Dynamics and Ecosystem Service Valuation in the Borana Rangeland, Southern Ethiopia: Linking Ecology and Carbon Finance

Rangelands are pivotal for global carbon cycling, climate regulation, and rural livelihoods, yet they are increasingly threatened by overgrazing, land-use conversion, and climate variability. Carbon storage serves as a key ecological indicator, reflecting both ecosystem health and the capacity of rangelands to contribute to climate mitigation. This study assessed carbon storage and its economic value in the Borana rangelands of southern Ethiopia between 2010 and 2024. Four major carbon pools, aboveground biomass, belowground biomass, soil organic carbon, and dead organic matter, were assessed and mapped using the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model. Results showed a total-carbon storage decline from 505.18 Mt C in 2010 to 503.93 Mt C in 2024, a net loss of 1.25 Mt C (0.25% of baseline stock). Spatial analysis revealed heterogeneous change patterns: intact bushlands and woodland retained the highest carbon densities, while heavily grazed and cultivated areas experienced substantial depletion. The associated economic valuation showed a Net Present Value loss of US$ 108.16 million over the 14-year period, with per-hectare economic value of carbon loss ranging between US$ 9,174 and 18,952. Although the magnitude of losses is relatively small compared to the total stock, the trend indicates a net release of carbon to the atmosphere, reducing the rangelands’ potential to function as a carbon sink. From an ecological and management perspective, these losses serve as an early-warning signal of rangeland degradation. Continued depletion will compromise forage availability, livestock productivity, and ecosystem resilience. Implementing sustainable grazing management and integrating carbon finance and restoration initiatives could enhance local resilience, improve carbon retention, and support pastoral livelihoods, enabling Borana to transition toward a climate-resilient carbon sink, delivering ecological, economic, and social co-benefits while contributing to national and global climate objectives.