Theoretical reconstructing the Green Sahara periods over the Quaternary

Theoretical reconstructing the Green Sahara periods over the Quaternary | 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 Research Article Theoretical reconstructing the Green Sahara periods over the Quaternary Hang Wang, Hu Yang, Xiaoxu Shi, Jiping Liu, Gerrit Lohmann, Jiawang Wu, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9553965/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract As Earth’s largest desert, the Sahara experienced periodic greening periods in the geological past, which has nurtured the earliest human civilizations. Traditionally, orbital forcing, particularly precession, has been considered the main control. However, geological records indicate that the Green Sahara periods (GSPs) were skipped in many precession cycles. In this study, we conducted a series of climate sensitivity simulations to quantify different forcings in contributing GSPs. Results reveal that, even though changes in Earth’s orbit exhibit the dominant contributor in regulating the pace of GSP, variations in atmospheric CO 2 , and ice sheet extent also play a modifying role. Using quantitative estimation, we developed a simple theoretical model to reconstruct the pace of GSPs by integrating only a few metrics, including Earth’s orbit parameters, atmospheric CO 2 level and eustatic sea level. In agreement with geological records, our theoretical reconstruction suggests that the skipped GSPs occurs more frequent throughout the Quaternary due to global cooling. Furthermore, we predict that the GSP will very likely skip again within the next precession cycle unless the atmospheric CO 2 emissions reach∼3,840 Pg. These findings provide a scientific basis for reconstructing Saharan paleoclimate and offer valuable insights for predicting its future climate change. Green Sahara periods Orbital forcing CO2 Ice sheet Full Text Additional Declarations The authors declare no competing interests. Supplementary Files supplementary.pdf Cite Share Download PDF Status: Posted 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. We do this by developing innovative software and high quality services for the global research community. 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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-9553965","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":631060753,"identity":"67a0df45-318a-444e-b231-80d789dd1ec5","order_by":0,"name":"Hang Wang","email":"","orcid":"https://orcid.org/0009-0006-9713-1999","institution":"School of Atmospheric Sciences, Sun Yat-Sen University and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai)","correspondingAuthor":false,"prefix":"","firstName":"Hang","middleName":"","lastName":"Wang","suffix":""},{"id":631060754,"identity":"0b8544bd-fc00-4e51-9b0c-a60aa4d85371","order_by":1,"name":"Hu Yang","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA3ElEQVRIiWNgGAWjYJACZgYGGwYGdjDjAAMbkVrSwCRJWg4jtBAEBsfPHn5d2HbeXreZgflzYdsdeT4G5mcP8Go5k5dmPbPtduI2oEXGM9ueGbYxsJkb4NVyIMfMmLftdoLZYf4PybxthxnbGHjYJPBqOf8GpOWcvRnQlsNALfaEtdzIMX7M23aAEegwxmaglkSCWiRvvDFj5jmXDPILM5BxOLmNmc0Mrxa+8znGn3nK7OzNjjcwAxmHbee3Nz/Dq0UBGHdoCpjxqQcC+QYG5g8E1IyCUTAKRsFIBwASvETLB8dJMwAAAABJRU5ErkJggg==","orcid":"","institution":"School of Atmospheric Sciences, Sun Yat-Sen University and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai)","correspondingAuthor":true,"prefix":"","firstName":"Hu","middleName":"","lastName":"Yang","suffix":""},{"id":631060755,"identity":"d4e5cd28-a2ef-4e91-906d-aee1d27a66c6","order_by":2,"name":"Xiaoxu Shi","email":"","orcid":"","institution":"School of Atmospheric Sciences, Sun Yat-Sen University and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai)","correspondingAuthor":false,"prefix":"","firstName":"Xiaoxu","middleName":"","lastName":"Shi","suffix":""},{"id":631060758,"identity":"c8d59a84-d513-47ba-8d7e-9004ddff6405","order_by":3,"name":"Jiping Liu","email":"","orcid":"","institution":"School of Atmospheric Sciences, Sun Yat-Sen University and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai)","correspondingAuthor":false,"prefix":"","firstName":"Jiping","middleName":"","lastName":"Liu","suffix":""},{"id":631060759,"identity":"a2535d77-dee8-4858-ad34-8e2951c15455","order_by":4,"name":"Gerrit Lohmann","email":"","orcid":"","institution":"Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research","correspondingAuthor":false,"prefix":"","firstName":"Gerrit","middleName":"","lastName":"Lohmann","suffix":""},{"id":631060762,"identity":"7cb58fd5-387f-4b17-bc97-9d64334d5fb2","order_by":5,"name":"Jiawang Wu","email":"","orcid":"","institution":"School of Marine Sciences, Sun Yat-Sen University and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai)","correspondingAuthor":false,"prefix":"","firstName":"Jiawang","middleName":"","lastName":"Wu","suffix":""},{"id":631060765,"identity":"cd67e03b-15cd-4850-b23c-22407ef288dd","order_by":6,"name":"Jun Tian","email":"","orcid":"","institution":"State Key Laboratory of Marine Geology, Tongji University","correspondingAuthor":false,"prefix":"","firstName":"Jun","middleName":"","lastName":"Tian","suffix":""},{"id":631060766,"identity":"ef10b091-d4ba-4543-8ddc-1f54b94a09ab","order_by":7,"name":"Francisco W. 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Traditionally, orbital forcing, particularly precession, has been considered the main control. However, geological records indicate that the Green Sahara periods (GSPs) were skipped in many precession cycles. In this study, we conducted a series of climate sensitivity simulations to quantify different forcings in contributing GSPs. Results reveal that, even though changes in Earth’s orbit exhibit the dominant contributor in regulating the pace of GSP, variations in atmospheric CO\u003csub\u003e2\u003c/sub\u003e, and ice sheet extent also play a modifying role. Using quantitative estimation, we developed a simple theoretical model to reconstruct the pace of GSPs by integrating only a few metrics, including Earth’s orbit parameters, atmospheric CO\u003csub\u003e2\u003c/sub\u003e level and eustatic sea level. In agreement with geological records, our theoretical reconstruction suggests that the skipped GSPs occurs more frequent throughout the Quaternary due to global cooling. Furthermore, we predict that the GSP will very likely skip again within the next precession cycle unless the atmospheric CO\u003csub\u003e2\u003c/sub\u003e emissions reach∼3,840 Pg. 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