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<p>Rapid urbanization in South Asia has significantly altered urban land surface characteristics, intensifying thermal stress and environmental degradation. This study aims to conduct a comparative geospatial assessment of urban environmental conditions and thermal stress across three major Pakistani cities: Lahore, Karachi, and Islamabad. The analysis is based on Landsat 8 satellite imagery (June 2024) and integrates four remote sensing indices: Normalized Difference Vegetation Index (NDVI), Normalized Difference Bareness Index (NDBaI), Land Surface Temperature (LST), and Urban Thermal Field Variance Index (UTFVI). Spatial analysis was performed using ArcGIS, with data acquired from the USGS Earth Explorer platform to ensure consistent cross-city comparison under uniform seasonal conditions. Islamabad demonstrated the most environmentally balanced conditions, with NDVI ranging from − 0.1338 to + 0.5777 and LST between 19.73&#xa0;°C and 36.69&#xa0;°C, indicating strong vegetation cover and lower thermal stress. Karachi exhibited the highest environmental degradation, with low NDVI (–0.1381 to + 0.5947), high impervious surface dominance, and elevated LST values (25.48&#xa0;°C to 41.19&#xa0;°C), reflecting severe urban heat stress. Lahore showed intermediate but more extreme thermal conditions, with the highest recorded LST range (26.34&#xa0;°C to 48.17&#xa0;°C), indicating significant urban heat island intensity despite moderate vegetation cover. UTFVI patterns further confirmed strong spatial variability in thermal stress across all cities. The study is based on a single-season Landsat dataset, which provides a spatially representative but temporally limited snapshot of urban thermal conditions. Additionally, uncertainties related to spatial resolution and emissivity correction may influence absolute temperature values.</p><p><b>Practical value</b>: The findings provide actionable insights for urban planners, supporting green infrastructure development, reflective building materials, and heat mitigation strategies aligned with sustainable urban development goals (SDGs 11 and 13).</p><p><b>Originality/Significance</b>: This study contributes a comparative multi-city geospatial framework that integrates vegetation, bare land, and thermal indicators, addressing a critical gap in spatially explicit urban environmental assessments in Pakistan.</p>

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Geospatial assessment of urban environmental and mitigation strategies for thermal stress in Lahore, Karachi, and Islamabad

  • 期刊论文

  • 发表日期：

    2026年6月18日

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  • Fizza Ejaz,
  • Anila Kausar,
  • Intikhab Ulfat,
  • Sergij Vambol,
  • Vladyslava Vambol,
  • Olena Lyndiuk

摘要

Rapid urbanization in South Asia has significantly altered urban land surface characteristics, intensifying thermal stress and environmental degradation. This study aims to conduct a comparative geospatial assessment of urban environmental conditions and thermal stress across three major Pakistani cities: Lahore, Karachi, and Islamabad. The analysis is based on Landsat 8 satellite imagery (June 2024) and integrates four remote sensing indices: Normalized Difference Vegetation Index (NDVI), Normalized Difference Bareness Index (NDBaI), Land Surface Temperature (LST), and Urban Thermal Field Variance Index (UTFVI). Spatial analysis was performed using ArcGIS, with data acquired from the USGS Earth Explorer platform to ensure consistent cross-city comparison under uniform seasonal conditions. Islamabad demonstrated the most environmentally balanced conditions, with NDVI ranging from − 0.1338 to + 0.5777 and LST between 19.73 °C and 36.69 °C, indicating strong vegetation cover and lower thermal stress. Karachi exhibited the highest environmental degradation, with low NDVI (–0.1381 to + 0.5947), high impervious surface dominance, and elevated LST values (25.48 °C to 41.19 °C), reflecting severe urban heat stress. Lahore showed intermediate but more extreme thermal conditions, with the highest recorded LST range (26.34 °C to 48.17 °C), indicating significant urban heat island intensity despite moderate vegetation cover. UTFVI patterns further confirmed strong spatial variability in thermal stress across all cities. The study is based on a single-season Landsat dataset, which provides a spatially representative but temporally limited snapshot of urban thermal conditions. Additionally, uncertainties related to spatial resolution and emissivity correction may influence absolute temperature values.

Practical value: The findings provide actionable insights for urban planners, supporting green infrastructure development, reflective building materials, and heat mitigation strategies aligned with sustainable urban development goals (SDGs 11 and 13).

Originality/Significance: This study contributes a comparative multi-city geospatial framework that integrates vegetation, bare land, and thermal indicators, addressing a critical gap in spatially explicit urban environmental assessments in Pakistan.