Spatio-Temporal Assessment of Green ‎Infrastructure Dynamics and Urban Heat Island ‎Mitigation Using Remote Sensing and GIS: Evidence ‎from Owerri Urban, Nigeria

Abstract

Rapid urbanisation has accelerated the loss of urban green infrastructure in many cities of the Global South, ‎intensifying Urban Heat Island (UHI) effects and posing significant challenges to sustainable urban development. ‎Despite growing interest in the cooling role of urban vegetation, limited attention has been given to integrating ‎long-term green infrastructure dynamics with thermal remote sensing to support spatially explicit planning ‎interventions in rapidly expanding secondary cities. This study evaluated the spatio-temporal distribution of ‎Green Infrastructure (GI) and its influence on urban thermal conditions in Owerri Urban, Nigeria, using multi-‎temporal Landsat imagery acquired in 2000, 2015, and 2025. Green Infrastructure maps, Normalized Difference ‎Vegetation Index (NDVI), and Land Surface Temperature (LST) were derived and analysed alongside correlation, ‎multiple linear regression, and spatial overlay techniques to investigate vegetation–temperature interactions and ‎identify priority greening zones. The results revealed a substantial decline in Green Infrastructure from 72.22% in ‎‎2000 to 26.43% in 2025, accompanied by a corresponding increase in non-green areas and progressively higher ‎land surface temperatures. Statistical analysis showed a strong negative relationship between NDVI and LST (r = -‎‎0.772, p < 0.001), while the regression model explained 72.9% of the spatial variation in LST (R² = 0.729), ‎confirming that vegetation density and built-up intensity are the principal determinants of urban thermal ‎conditions. Spatial overlay analysis further identified priority greening zones where strategic vegetation ‎restoration is expected to provide the greatest cooling benefits. This study demonstrates that integrating green ‎infrastructure assessment with thermal remote sensing and spatial prioritisation provides a practical decision-‎support framework for climate-responsive urban planning. The findings highlight the importance of protecting ‎and expanding urban green infrastructure as a nature-based solution for mitigating Urban Heat Islands, for ‎strengthening climate resilience, and advancing sustainable urban infrastructure‎.