Evaluating the Effectiveness of the Great Green Wall Programme Using Remote Sensing in Kebbi State

The Great Green Wall initiative is Nigeria's flagship programme for combating desertification and land degradation across the Sahel belt. This study evaluates the spatial effectiveness of the Great Green Wall Programme in Kebbi State by comparing vegetation conditions within programme intervention areas against matched control sites using remote sensing. Sentinel-2 imagery from 2016 and 2023 is used to produce vegetation cover maps and compute NDVI, Fractional Vegetation Cover, and Bare Soil Index for 45 intervention and 45 matched control plots across Birnin Kebbi and Argungu LGAs. A difference-in-differences spatial analysis framework controls for pre-intervention vegetation baselines and rainfall differences. Results demonstrate statistically significant vegetation improvement in programme areas compared to control sites, with mean NDVI increasing by 0.12 units more in intervention areas over the seven-year period. However, spatial heterogeneity in outcomes is documented, with areas lacking community co-management showing limited vegetation response. Keywords: Great Green Wall, remote sensing, Kebbi State, desertification, programme evaluation