Abstract
<title>Abstract</title> <p>Rapid urbanization and climate change are intensifying urban heat stress in many developing countries, particularly in densely populated and climate-vulnerable regions. In Khulna City Corporation (KCC), Bangladesh, rapid land use and land cover (LULC) transformation has increased exposure to the Urban Heat Island (UHI) effect, posing growing threats to public health, livelihoods, and urban sustainability. However, the combined influence of urban expansion, thermal dynamics, and heatwave-induced socio-economic vulnerability remains insufficiently understood. The spatiotemporal relationship between LULC change, land surface temperature (LST), UHI intensity, and socio-economic vulnerability using Google Earth, statistical analyses, principal component analysis (PCA), and household survey data are presented. Vegetation cover shrank from 72.21% to 45.09% while built-up areas expanded from 10.12% to 32.16% from 1995 to 2025. LST over 40°C increased from 44% in 2015 to 67% in 2025. Correlation analysis showed a high positive association between LST and UHI intensity (r ≈ 0.99) while NDVI was negatively correlated with LST, implying a cooling effect of vegetation. PCA showed LST, NDBI, and LULC were the most significant factors determining urban thermal variation. Survey results showed sleep disruption (36.7%) and heat-related discomfort (35.6%) were the most common impacts. Pregnant women (55.2%), elderly people (31.6%), and outdoor workers (27.5%) were identified as the most vulnerable groups. Heatwaves also reduced productivity and worsened water shortages (40%), food prices (23.8%), and power shortages. Results show that fast urban expansion and loss of green space are increasing heat exposure and socio-economic vulnerability in KCC. The study provides evidence to support climate-sensitive urban planning, green infrastructure development, and targeted adaptation strategies to improve urban resilience in fast-growing coastal cities.</p>