Assessing the Impact of Climate Change on Land Use Dynamics in Osun River Basin Nigeria

Abstract

Gaining deep insight into how climate change shapes land use and land cover (LULC) dynamics is vital for ensuring sustainable management of watersheds, especially in sensitive environments like the Osun River Basin (ORB) in southwestern Nigeria. This research explores the spatio-temporal trends in LULC transformations across the ORB between 2002 and 2022, and critically examines how core climatic factors, including temperature, rainfall, and the Vegetation Condition Index (VCI), influence these shifts. Multi-temporal Landsat satellite imagery for 2002, 2012, and 2022 of 30m resolution was analysed using supervised classification and change detection techniques in a GIS environment, complemented by rainfall and temperature data derived from CHIRPS and MODIS. Results reveal significant LULC transformations over the two decades, with built-up areas expanding by over 154%, bare surfaces increasing by approximately 19%, while croplands and forest areas declined by 25% and 6%, respectively. The Multiple Linear Regression (MLR) model showed that climate variables collectively explain about 78% of the variance in built-up area expansion (R² = 0.78, p < 0.001). Temperature emerged as the strongest positive predictor, indicating that a 1°C rise could result in an increase of approximately 120km² of built-up land, whereas rainfall demonstrated a stabilising effect by sustaining vegetation cover. The analysis of spatial rainfall and VCI patterns further revealed a progressive decline in vegetation health, with pronounced stress observed in the basin’s central and northern regions, driven by rising temperatures, erratic rainfall, and intensified anthropogenic activities such as urbanisation, deforestation, and unsustainable land management. These combined pressures have profound implications for agricultural productivity, biodiversity conservation, and water resource sustainability in the basin.