Mapping urban heat islands in Durban (2010–2025): A cross-sectional remote sensing study.

Sibonelo Thanda Mbanjwa

doi:10.51168/sjhrafrica.v7i3.2213

Authors

Sibonelo Thanda Mbanjwa Mangosuthu University of Technology P.O. Box 12363 Jacobs 4026 Durban, South Africa

DOI:

https://doi.org/10.51168/sjhrafrica.v7i3.2213

Keywords:

Urban heat islands, Remote sensing, Land Surface Temperature, Landsat, Sentinel-2, Spatio-temporal analysis, Land-cover change, GIS, Durban, Urbanization, Climate adaptation, Thermal hotspots

Abstract

Background
Urban heat islands (UHIs) occur when built-up surfaces absorb and retain heat, causing higher temperatures in urban areas than in surrounding natural environments. Durban has undergone rapid urban expansion over the past decade, potentially intensifying UHI effects and increasing heat-related risks. Remote sensing provides a reliable method to monitor long-term surface temperatures and associated land-cover changes. This study mapped spatio-temporal UHI patterns in Durban between 2010 and 2025 and examined their relationship with land-cover transformation.

Methods:

A spatio-temporal remote sensing design was used. Landsat 7, Landsat 8 (USGS), and Sentinel-2 (Copernicus) satellite images were acquired for 2010, 2015, 2020, and 2025, focusing on dry-season scenes to reduce cloud interference. Land Surface Temperature (LST) was computed using mono-window and split-window algorithms. Land-cover classes were generated through supervised classification and validated using Google Earth reference points. Change-detection techniques quantified vegetation loss, built-up expansion, and temperature shifts. Spatial analysis in the Geographic Information System was used to examine the relationship between LST and land-cover type.

Results
Surface temperatures increased steadily between 2010 and 2025. The highest LST values were concentrated in the CBD, industrial areas, and rapidly urbanising townships. Vegetated spaces and coastal zones remained significantly cooler. Classification results showed a notable increase in impervious surfaces and a corresponding decline in natural vegetation. Hotspot maps confirmed a clear expansion of UHI zones over time, strongly linked to land-cover conversion from green space to built environments.

Conclusion
Urban growth in Durban has intensified UHI effects over the last 15 years. Built-up surfaces consistently recorded higher temperatures than vegetated and coastal areas, demonstrating the moderating role of green infrastructure.

Recommendations
Urban greening, protection of remaining natural areas, and adoption of reflective or permeable building materials are recommended. Continued satellite monitoring should inform climate-adaptation and heat-risk mitigation planning.

Author Biography

Sibonelo Thanda Mbanjwa, Mangosuthu University of Technology P.O. Box 12363 Jacobs 4026 Durban, South Africa

is a dedicated lecturer in the Department of Nature Conservation at Mangosuthu University of Technology (MUT), South Africa. He holds a Ph.D. in Environmental Science and specializes in biodiversity conservation, sustainable development, and environmental education. Dr. Mbanjwa is deeply committed to community engagement, student mentorship, and the integration of indigenous knowledge systems into conservation practices. His work bridges academia and practical application, empowering students and communities through innovative teaching, research, and outreach initiatives.

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