Assessing the Impacts of Urban Heat Islands on Vulnerable Populations in Lagos, Nigeria: A Spatiotemporal Analysis Using Remote Sensing and GIS

Project Abstract

Urban heat islands (UHIs) amplify heat exposure in rapidly expanding Lagos through dense built environments, limited green space, and complex socio-economic disparities, necessitating a spatiotemporal assessment that integrates remote sensing and GIS to quantify differential thermal exposure across vulnerable populations. This study leverages multi-year Landsat and Sentinel imagery (2015–2024) to derive land surface temperature (LST) and urban morphology indices, coupled with high-resolution socio-demographic datasets from census and household surveys to map exposure, sensitivity, and adaptive capacity indicators at the neighborhood scale. We implement a robust methodological framework that includes (i) preprocessing and atmospheric correction of satellite data, (ii) generation of LST using split-window and radiative transfer algorithms validated against in-situ thermistor data from strategically deployed meteorological stations, (iii) urban heat intensity metrics such as mean, maximum, and diurnal temperature ranges, (iv) urban green/blue space and surface albedo assessment from multispectral bands, and (v) integration with GIS-based vulnerability indices that account for age, income, housing quality, health status, and access to cooling resources. Spatial autocorrelation and hotspot analysis reveal persistent heat hotspots in high-density informal settlements, commercial corridors, and low-tree-cover districts, with pronounced diurnal and seasonal variability linked to synoptic weather patterns and urban morphology. Temporal trend analysis demonstrates accelerating UHI effects during dry seasons and heatwaves, coinciding with increased energy demand and strained public health systems. The study then couples exposure assessment with health vulnerability data to estimate differential heat-related risk, validating results through health outcome records and self-reported morbidity indicators. Scenario modeling investigates the potential mitigating impact of urban greening, reflective roof technologies, and water-sensitive urban design under varying climate projections, providing a decision-support tool for policymakers. Key findings indicate that vulnerable groups—elderly, low-income households, and residents of informal settlements—experience disproportionately higher exposure and lower adaptive capacity, with a cumulative risk index exceeding city-wide averages by up to 40% in identified hotspots. The research also uncovers spatial spillover effects where urban cooling corridors influence adjacent neighborhoods, highlighting the importance of targeted zoning and infrastructure investments. Policy implications emphasize prioritizing equity-centered UHI mitigation, expanding climate-resilient housing, expanding green and blue infrastructure, and integrating heat-health warning systems with urban planning processes. The study contributes to methodological advancements in integrating remote sensing-derived thermal metrics with socio-spatial vulnerability frameworks in a rapidly growing West African megacity, offering scalable approaches for other tropical urban contexts. Limitations include data gaps in high-resolution socio-economic datasets, sensor saturation during extreme heat events, and uncertainties in LST-to-air temperature translation, which are addressed through cross-validation, uncertainty quantification, and sensitivity analyses. The outcomes provide a comprehensive, spatially explicit understanding of how UHIs intersect with socio-economic vulnerability to shape health and well-being, informing evidence-based adaptation strategies for Lagos and similar urban environments.

Project Overview

What This Project Is About

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A straightforward study that looks at how urban areas in Lagos become hotter than surrounding areas and how this affects vulnerable groups like the elderly, children, and low-income residents. It uses simple maps and temperature data to understand where heat problems are strongest and why.

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The Problem It Addresses

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Cities often trap heat, creating urban heat islands that raise health risks and energy use. In Lagos, dense neighborhoods may experience higher heat exposure, which can worsen heat-related illnesses and reduce living comfort. The project fills gaps in local heat mapping and how it affects vulnerable people.

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Objectives of the Project

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1. Identify hotspots where temperatures are highest in Lagos.
2. Assess how different neighborhood characteristics relate to heat levels.
3. Evaluate which groups are most at risk based on population and socio-economic data.
4. Explore changes in heat patterns over time using simple, repeatable methods.
5. Provide clear, practical recommendations for reducing heat exposure in targeted areas.

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What You Will Do Step by Step

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1. Explain basic concepts of urban heat islands in plain language.
2. Collect publicly available temperature data and land-use maps for Lagos.
3. Create simple maps showing heat hotspots with basic GIS tools.
4. Combine temperature data with population information to identify vulnerable groups.
5. Analyze how built forms (like buildings and roads) relate to heat levels.
6. Summarize findings in a clear report with visual explanations.
7. Suggest low-cost strategies to reduce heat exposure in targeted areas.

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Expected Outcome

A clear set of heat hotspot maps and a short analysis showing which communities are most at risk, plus practical ideas for planners and residents to reduce heat exposure.