Building a Household Heat Vulnerability Index for Farming Communities: Evidence from Two Case Study Sites in Rural Bangladesh

Extreme heat is an emerging threat to rural livelihoods in South Asia, yet existing heat vulnerability assessments often overlook household-level experiences. This study develops and validates a Household Heat Vulnerability Index (HHVI) based on subjective heat-risk perceptions for farming communities in Bangladesh. Survey data from 362 farming households in drought-prone Natore and salinity-prone Khulna were used to construct the HHVI from 22 indicators representing exposure, sensitivity, and adaptive capacity dimensions of the IPCC AR4 vulnerability framework. Indicators were identified through literature review, qualitative interviews, and pilot testing, then normalized and aggregated into a composite index. Households in both regions experienced high heat exposure; however, vulnerability differs substantially across locations and households. Mean HHVI scores were higher in Natore (0.531 ± 0.057) than in Khulna (0.484 ± 0.059; p < 0.001). While exposure and sensitivity varied only modestly across sites, adaptive capacity showed the largest difference among the vulnerability dimensions. Differences in irrigation practices, access to early warning information, housing conditions, and exposure to compound hazards highlight how local environmental and household circumstances contribute to contrasting vulnerability. The positive association between HHVI scores and subjective heat-risk perceptions supports the index’s validity. These findings demonstrate that similar heat exposure can produce unequal vulnerability outcomes. Household-level assessments provide insights that could be missed by temperature-based or census-derived approaches. Moreover, household approaches can support more targeted heat adaptation planning for farming communities facing increasing climate extremes.