Urban Heat Island Hazard and disaster risk in major Pakistani cities: Spatiotemporal analysis, vulnerability assessment, and risk reduction strategies

Urban Heat Islands (UHI) represent a growing climate-associated disaster risk in rapidly urbanizing cities, where expanding impervious surfaces, declining vegetation, and weak governance intensify thermal hazard and population vulnerability. This study presents a spatiotemporal analysis of UHI hazard, vegetation-temperature dynamics, and urban expansion across four Pakistani cities using MODIS and Landsat 8 imagery, Pakistan Meteorological Department records, and urban planning documents spanning 2000 to 2023, integrated through GIS spatial analysis, Pearson correlation, and linear regression. Karachi recorded the highest urban-rural temperature differential at 4.5 °C, followed by Lahore (4.1 °C), Faisalabad (3.8 °C), and Islamabad (2.5 °C). A strong inverse NDVI-LST correlation (mean r = −0.76, p < 0.01) was confirmed across all cities, establishing vegetation loss as the primary controllable driver of thermal hazard. Annual temperatures rose 0.12 to 0.16 °C per year, heatwave days doubled in Lahore and Faisalabad, and urban expansion ranged from 34% to 62% between 2000 and 2022 without green infrastructure integration. All four cities lack heat action plans, climate-sensitive zoning, and mandatory green coverage standards, with low-income settlements bearing disproportionate thermal exposure. A multi-tiered disaster risk reduction framework aligned with the Sendai Framework 2015–2030 is proposed, encompassing urban greening mandates, heat early-warning systems, climate-resilient zoning, and ecological buffer preservation. • Karachi shows highest UHI intensity at 4.5 °C urban-rural differential (2000–2023). • NDVI-LST inverse correlation ( r = −0.76) confirmed across all four Pakistani cities. • Urban expansion of 34–62% occurred without any green infrastructure integration. • No city has a heat action plan despite heatwave days doubling in Lahore and Faisalabad. • Sendai-aligned DRR framework proposed linking thermal hazard to governance gaps.