Urbanization induced heat wave risk assessment of Khulna City, Bangladesh: A 30-years analysis of land surface temperature, climate trends and forecasting

This study examines how urbanization has influenced heatwave risk in Khulna, Bangladesh, from 1993 to 2023 by analyzing changes in land surface temperature (LST) and land use land cover (LULC) using satellite imagery and statistical methods. Over the 30‐year period, mean LST rose by 7 °C, with 23.7 % of Khulna now classified as an excessive heat zone. The Mann–Kendall (MK) test and Sen’s slope (SS) estimator confirm a significant warming trend, particularly during the warmest months. Pearson correlation (PC) analysis indicates a negative relationship between temperature and humidity, exacerbating heatwave severity. LULC results reveal that urbanized areas have expanded approximately threefold while vegetation cover has decreased by nearly 50 %. Using a seasonal-trend decomposition based on LOESS with an auto regressive integrated moving average (STL‐ARIMA) model, the study forecasts 29 additional heatwave days exceeding 36 °C over the next five years. This projection suggests a likely intensification of the urban heat island (UHI) effect driven by rapid urban growth and diminished natural spaces, heightening heat‐related hazards. The findings support the need for sustainable urban development strategies in Khulna, such as increasing green cover and improving water management to inform policy interventions aimed at mitigating rising heat risks in the city’s expanding urban environment.