Heatwaves, Human Thermal Stress and Socioeconomic Vulnerability: A District‐Level Heat‐Risk Assessment of Bundelkhand, India

ABSTRACT

Heatwaves are amongst the most severe climate‐related hazards in semi‐arid regions, posing increasing threats to human health, livelihoods and environmental sustainability. This study investigated the spatiotemporal characteristics of heatwaves and human thermal stress across the Bundelkhand region of India during 1981–2024 using the India Meteorological Department (IMD) heatwave criteria and the universal thermal climate index (UTCI). Heatwave characteristics were integrated with thermal stress exposure, socioeconomic vulnerability and long‐term trend analyses to develop a district‐level composite heat‐risk assessment. Bundelkhand experienced persistent and spatially heterogeneous heatwave conditions, with a mean annual frequency of 1.80 ± 1.26 (IMD) and 1.73 ± 1.18 (UTCI) independent heatwave events, corresponding to 11.61 ± 8.41 and 11.41 ± 8.13 heatwave days year ⁻¹ , respectively. Mean heatwave duration exceeded 5.8 days, whilst maximum event intensity reached 5.05°C ± 2.16°C above the IMD threshold and 3.10°C ± 1.48°C above the UTCI threshold. The pre‐monsoon season (April–June) represented the period of greatest thermal stress, with mean monthly maximum temperature reaching 41.15°C ± 1.24°C in May and mean UTCI exceeding 36°C. Mann–Kendall analysis identified significant ( p  < 0.05) increases in annual maximum UTCI across seven districts and in extreme heat‐stress exposure across eight districts, with Hamirpur exhibiting the strongest increase (Sen's slope = 7.91, p  = 0.001). Lalitpur (0.80), Chitrakoot (0.77), and Chhatarpur (0.70) were identified as the most critical heat‐risk hotspots based on the composite index. These findings demonstrate that heat‐related risk in Bundelkhand is shaped by the combined effects of increasing heatwave activity, intensifying thermal stress and socioeconomic vulnerability, providing a robust scientific basis for district‐level heat adaptation planning, early‐warning systems and climate‐resilient public health interventions.