Characterising Spatial Patterns of Exposure, Sensitivity and Adaptive Capacity to Assess Heatwave Vulnerability of Bangladesh

Considering the effects of the climate change, the heat waves are becoming one of the most significant and least researched environmental hazards in Bangladesh, while determination of the areas most vulnerable to increased temperatures and frequent heat waves is necessary for preparing firm climate adaptation plans. This study explores Bangladesh's heatwave vulnerability by developing three composite indices related to heatwave vulnerability, including- exposure, sensitivity, and adaptive capacity, and was analyzed using district-level data. Exposure was measured using land surface temperature (LST) and population density, while sensitivity included the elderly, very young, and female population, illiteracy rate, built-up area, poverty, access to water, unemployment, occupation, and disability. Adaptive capacity was calculated using vegetation cover, water resources, and electricity access (proxied by average radiance of nighttime light). Using both spatial and statistical methods, the data were normalized and aggregated to obtain indices of heatwaves. Findings revealed significant regional disparities, with a high degree of exposure found in regions where high temperatures are combined with considerable population, such as Dhaka, Rajshahi and Chattogram, and the strongest sensitivity in Rangpur and coastal regions where the population is economically vulnerable. The country could be lacking infrastructures that could moderate the effects of the enormous heat in the north and south parts of the country. The statistical validity of differences in the indices of vulnerability across the country was confirmed by the use of Kruskal-Wallis H test. The variance of sensitivity and adaptive capacity was large, with the distribution of the exposure, being less variable. In addition, a heatwave vulnerability triangle was constructed to visualize the regional disparity in the exposure, sensitivity, and adaptive capacity. The sensitivity analysis was used to confirm the strength of the indices, which revealed that LST, vegetation cover, and waterbodies are the strongest indicators that determine the vulnerability of the districts. Overall, the spatial analysis indicates in order to adapt to the heat and build the resilience to heat in Bangladesh, it is critical to prioritize the most vulnerable and least ready areas.