Climate Change Impact on the Heat Index in India: Seasonal and Spatial Analysis Using CMIP6 Projections

Climate Change Impact on the Heat Index in India: Seasonal and Spatial Analysis Using CMIP6 Projections | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Climate Change Impact on the Heat Index in India: Seasonal and Spatial Analysis Using CMIP6 Projections M. O. Molina, P. M.M. Soares, A. Agarwal, R. M. Trigo This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7022442/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 16 Jan, 2026 Read the published version in Scientific Reports → Version 1 posted 10 You are reading this latest preprint version Abstract This study investigates the climate change signal on mean and extreme temperatures in India, adding new insight by using the state-of-the-art CMIP6 projections to quantify the seasonal and spatial evolution of the Heat Index (HI) across India.; offering one of the first national-scale assessments combining temperature and humidity under Shared Socioeconomic Pathways (SSPs) scenarios. To assess the recent past climate change signal on those properties, ERA5 reanalysis data are used. CMIP6 models realistically reproduce historical warming patterns during winter (DJF) and pre-monsoon (MAM) seasons but tend to underestimate extreme summer (JJA) conditions. Results show a significant warming trend since 1980, characterized by an increased frequency of hot extremes, particularly during winter, with an increase of monthly hot anomalies of 2.15%. Then, future daily HI is calculated from mean temperature and relative humidity from CMIP6 global climate models (GCMs). Future projections indicate a substantial increase in both the frequency and persistence of dangerous HI levels across India, driven by rising temperatures and regionally variable humidity trends. By mid-21st century (2041–2070), the annual number of days with dangerously high HI values (27º and 32ºC) is projected to rise by more than 20 and 10 days, respectively, compared to 1971–2000. By the late century (2071–2100) under the SSP5-8.5 scenario, the HI will be above 27ºC (32ºC) during more than 75 (5) absolute days per year in JJA and more than 20 (1) days in MAM. Critical HI days will be highest in coastal regions in winter and more northern regions in summer, increasing towards northern latitudes with the emission scenario. These findings underscore the importance of region-specific adaptation strategies, as heat stress future anomalies will differ across India. Understanding these spatiotemporal patterns is critical for effective climate adaptation and public health policies aimed at mitigating the increasing risks associated with extreme heat events. Earth and environmental sciences/Climate sciences Earth and environmental sciences/Environmental sciences heat-index CMIP6 India climate change extremes Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 16 Jan, 2026 Read the published version in Scientific Reports → Version 1 posted Editorial decision: Revision requested 06 Oct, 2025 Reviewers agreed at journal 25 Aug, 2025 Reviews received at journal 07 Aug, 2025 Reviewers agreed at journal 09 Jul, 2025 Reviewers agreed at journal 09 Jul, 2025 Reviewers invited by journal 09 Jul, 2025 Editor assigned by journal 09 Jul, 2025 Editor invited by journal 07 Jul, 2025 Submission checks completed at journal 04 Jul, 2025 First submitted to journal 04 Jul, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7022442","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":483198815,"identity":"f1ecabc3-308e-4881-bb20-573d1334b66d","order_by":0,"name":"M. O. 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