The Impact of Climate Change on Land Degradation in Najaf Governorate, Iraq

Land degradation in dryland regions is strongly influenced by climate variability and limited water availability. However, long-term relationships between climate drivers and vegetation dynamics remain poorly understood in many dryland regions of Iraq. This study investigates the influence of precipitation and land surface temperature (LST) on vegetation dynamics and land degradation in Najaf Governorate using 22 years of satellite observations (2001–2022), climate datasets, and land cover-specific analyses. The NDVI from MODIS, precipitation from CHIRPS, and LST from MODIS were used and validated with ground-based meteorological stations. The Aridity Index (AI) was calculated to characterize regional dryness, confirming that Najaf remains arid. Climate–vegetation relationships were evaluated at the regional scale, across 64 sampling points, and among ten land cover classes using 448 ground truth points. Results show that precipitation had a weak but detectable relationship with NDVI at the regional scale (R = 0.25), while LST showed a weak negative relationship with NDVI (R = −0.30), mainly reflecting seasonal differences between vegetation growth and temperature conditions rather than direct thermal limitation. However, land cover-specific analysis revealed stronger responses: palm showed a positive response to precipitation (R = 0.35), irrigated cropland showed strong sensitivity to LST (R = −0.85), and shrubland showed a weak precipitation response (R = 0.23). Partial correlation analysis confirmed that precipitation had significant independent effects on palm (R = 0.61) and shrubland (R = 0.48), whereas LST showed significant relationships mainly with water bodies (R = 0.87) and shrubland (R = 0.44). These results indicate that precipitation is the dominant climatic control on vegetation variability in Najaf, while LST effects are spatially variable and mainly dependent on land cover characteristics. This study provides a long-term assessment of climate–NDVI relationships in a dry environment and establishes a baseline for understanding climate-driven land degradation under increasing water limitations.