Climate models exaggerate the impact of greenhouse gases on recent interhemispheric temperature contrast and tropical climate

Climate models exaggerate the impact of greenhouse gases on recent interhemispheric temperature contrast and tropical climate | 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 models exaggerate the impact of greenhouse gases on recent interhemispheric temperature contrast and tropical climate Chengfei He, Amy Clement, Mark Cane, Alex Gonzalez, Young-Oh Kwon, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6760163/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 27 Feb, 2026 Read the published version in Nature Communications → Version 1 posted You are reading this latest preprint version Abstract The interhemispheric thermal contrast (IHTC), represented by sea surface temperature (SST) differences between the northern (NH) and southern (SH) hemispheres, crucially influences the tropical climate. Current CMIP6 climate models, however, struggle to accurately simulate the IHTC and associated tropical climate variability. Here, we show that simulated long-term trends since 1950 in models are consistently higher, with more warming in the NH compared to the SH, than in observations. This systematic discrepancy arises from overly dominant role of greenhouse gases in models that yields a positive IHTC through wind-evaporation-SST feedback. Conversely, the observed trend, primarily driven by anthropogenic and natural aerosols, is negative. This discrepancy suggests that current models is overly sensitive to greenhouse gases, and actual equilibrium climate sensitivity (ECS) may be lower than CMIP6 model predictions. Nevertheless, the modeled multidecadal IHTC variability aligns with observations, enabling a constrained estimate of effective radiative forcing due to aerosol-cloud interactions (ERFaci) at -0.6±0.3 W/m^2, with a “likely” range 57% narrower than the latest IPCC report. Our study further suggests that future tropical rain belt shifts are likely to be less pronounced than predicted by CMIP6 models with the high ECS. Earth and environmental sciences/Climate sciences/Climate change Earth and environmental sciences/Climate sciences/Atmospheric science Full Text Additional Declarations There is NO Competing Interest. Supplementary Files SupplementalTable1.xlsx CMIP6 models used in present study ExtendedDataFig.pdf Fig. S1-S11 Cite Share Download PDF Status: Published Journal Publication published 27 Feb, 2026 Read the published version in Nature Communications → Version 1 posted 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. 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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-6760163","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":465819377,"identity":"fe45fb5f-53ce-4d8a-ab40-2118eb8bfd34","order_by":0,"name":"Chengfei He","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA5UlEQVRIiWNgGAWjYDACCQY2BoYKEIsHSZQHh2qEljNABhtYmQGRWhjbSNHCP7uB7cHHeXfkzOf3Hnzw488fOfPZDYwP3rbhseTOAXbDmdueGcsc40s27G0zMJa5c4DZcC4eLQYSCWzSvNsOJ85g4zGT4G0wSJwBFiGk5e8csBbzn3/+GNQDtbD/JqiFsQFiCzMPm0GCBFCEGZ8WiRuJbZI9xw4bS7DlGEvLthkbzpBIbJaccw63Fv4ZycckftQclpNgPmP48c0fOXkJieSDH96U4dbCwMDYQFhkFIyCUTAKRgGJAACdHUgePbhNCwAAAABJRU5ErkJggg==","orcid":"https://orcid.org/0000-0003-1453-9691","institution":"Northeastern University","correspondingAuthor":true,"prefix":"","firstName":"Chengfei","middleName":"","lastName":"He","suffix":""},{"id":465819378,"identity":"6f484825-e621-4ee0-9ae8-2810423816e8","order_by":1,"name":"Amy Clement","email":"","orcid":"https://orcid.org/0000-0002-0105-0961","institution":"University of Miami","correspondingAuthor":false,"prefix":"","firstName":"Amy","middleName":"","lastName":"Clement","suffix":""},{"id":465819379,"identity":"b5e074a4-de33-45a1-a285-ed74a8e7b006","order_by":2,"name":"Mark Cane","email":"","orcid":"https://orcid.org/0000-0001-5408-2388","institution":"Columbia University","correspondingAuthor":false,"prefix":"","firstName":"Mark","middleName":"","lastName":"Cane","suffix":""},{"id":465819380,"identity":"2a1e8a0b-3212-4b6f-b896-bd1ae82c5904","order_by":3,"name":"Alex Gonzalez","email":"","orcid":"","institution":"Woods Hole Oceanographic Institution","correspondingAuthor":false,"prefix":"","firstName":"Alex","middleName":"","lastName":"Gonzalez","suffix":""},{"id":465819381,"identity":"7875fd2d-3fc8-4c7a-995e-bab569bedadd","order_by":4,"name":"Young-Oh Kwon","email":"","orcid":"https://orcid.org/0000-0002-1241-2817","institution":"Woods Hole Oceanographic Institution","correspondingAuthor":false,"prefix":"","firstName":"Young-Oh","middleName":"","lastName":"Kwon","suffix":""},{"id":465819382,"identity":"585b0309-04b5-4f79-8ec4-0945aff1078e","order_by":5,"name":"Jia-Rui Shi","email":"","orcid":"","institution":"Courant Institute - 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