Land-Cover Change and Predictive Modeling of Urban Heat Dynamics in Kano, Nigeria

Abstract

Urbanisation profoundly alters land-use and land-cover (LULC) patterns, often intensifying urban heat island (UHI) effects and threatening sustainable development. In rapidly growing semi-arid cities such as Kano Metropolis, Nigeria, these dynamics remain underexplored. This study investigates the relationship between LULC transitions and urban thermal dynamics over nearly four decades (1984 - 2023), while also forecasting future changes. Multi-temporal Landsat imagery was classified using the Classification and Regression Tree (CART) algorithm, achieving overall accuracies ranging from 92.1% to 98.5% and Kappa coefficients exceeding 0.85. Vegetation and built-up indices, including the Normalised Difference Vegetation Index (NDVI) and Normalised Difference Built-up Index (NDBI), were analysed alongside Land Surface Temperature (LST) to assess urban heat patterns. Predictive modelling employed the Cellular Automata Artificial Neural Network (CA-ANN) approach, which was validated with an overall accuracy of 92% and a Kappa coefficient of 0.86. Results show that built-up areas expanded from 43.06 km² (2.93%) in 1984 to 381.79 km² (25.95%) in 2023, an almost 800% increase, while bare land declined by 23.2%. Mean LST rose from 39.7°C in 1984 to 41.5°C in 2023, with peak values exceeding 52°C in 2010. A strong positive correlation was found between NDBI and LST (r = 0.57), while NDVI showed a negative correlation with LST (r = -0.32), highlighting the cooling effect of vegetation. Model simulations predict continued urban expansion through 2050, with built-up areas increasing by 6.5% and further intensification of UHI effects if unchecked. These findings emphasise the urgent need for sustainable urban planning, including the preservation of vegetation cover, the development of green infrastructure, and climate-sensitive construction practices. The study offers critical insights for policymakers and urban planners seeking to mitigate thermal stress and foster climate-resilient urban development in sub-Saharan Africa.