Sahithi et al. (2025) Rising compound heatwave exposure in India: insights from CMIP6 climate model projections

⚠️ Warning: This summary was generated from the abstract only, as the full text was not available.

Identification

• Journal: Environmental Research Letters
• Year: 2025
• Date: 2025-10-17
• Authors: Karlapudi Sahithi, Jew Das
• DOI: 10.1088/1748-9326/ae1498

## Research Groups -

Short Summary

This study analyzes the variability of daytime-only, nighttime-only, and compound heat waves (HWs) and their impact on population exposure across India under various Shared Socioeconomic Pathways (SSPs) scenarios. The findings project significant increases in compound and nighttime-only HWs and associated population exposure, particularly in Northwest and Central Northeast India, while daytime-only HWs may decline in some regions.

Objective

• What effects might compound heatwaves have under climate change scenarios?
• How are compound heatwaves expected to impact the population in the future?

Study Configuration

• Spatial Scale: India, including Northwest India (NWI), Central Northeast India (CNI), and the Himalayan region.
• Temporal Scale: Future projections, specifically after 2060 and for the period 2061–2100.

Methodology and Data

• Models used: Climate projections from the Coupled Model Intercomparison Project Phase 6 (CMIP6) experiment, utilizing Shared Socioeconomic Pathways (SSP126, SSP245, SSP370, and SSP585) scenarios.
• Data sources: Climate model outputs from CMIP6 under SSP scenarios.

Main Results

• Compound heat waves (HWs) are projected to increase by 4.6 events annually in Northwest India (NWI) under the SSP585 scenario.
• Daytime-only HWs are expected to decline after 2060, except in the Himalayan region, potentially due to changes in monsoon patterns and increased evaporative cooling.
• Nighttime-only HWs are anticipated to uniformly increase across all regions and scenarios, with the most substantial rises observed in Central Northeast India (CNI) and NWI.
• Under the SSP370 scenario during 2061–2100, population exposure to compound HWs and nighttime-only HWs is projected to increase substantially across all regions.
• Specifically, exposure to compound HWs is anticipated to exceed historical levels by more than 30 times in most regions.
• Both the CNI and NWI regions show the highest rise in compound and nighttime-only heat wave extremes.

Contributions

• Provides a comprehensive analysis of the variability and population exposure impacts of daytime-only, nighttime-only, and critically, compound heat waves across India under CMIP6 SSP scenarios.
• Offers a substantial scientific foundation for policymakers to inform and enhance heat action plans at national, state, and local levels.

## Funding -

Citation

@article{Sahithi2025Rising,
  author = {Sahithi, Karlapudi and Manikanta, Velpuri and Das, Jew},
  title = {Rising compound heatwave exposure in India: insights from CMIP6 climate model projections},
  journal = {Environmental Research Letters},
  year = {2025},
  doi = {10.1088/1748-9326/ae1498},
  url = {https://doi.org/10.1088/1748-9326/ae1498}
}