Model-data synthesis of benthic isotopes suggests a warmer Miocene Climatic Optimum

Model-data synthesis of benthic isotopes suggests a warmer Miocene Climatic Optimum | 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 Model-data synthesis of benthic isotopes suggests a warmer Miocene Climatic Optimum Feng Zhu, Jiang Zhu, Weimin Si, Jared Nirenberg, Timothy Herbert, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7124543/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted You are reading this latest preprint version Abstract The global warmth of the Miocene Climatic Optimum (MCO, ~15 Ma) offers valuable insights into warm climate dynamics and future climate change, providing a real-world testbed for validating climate models. However, the magnitude of MCO warmth remains uncertain due to the scarcity and inherent uncertainties of surface temperature proxy records. Existing estimates based on benthic isotopes, which leverage the relatively homogeneous nature of the deep ocean and therefore require fewer records, suggest that the MCO global mean surface temperature (GMST) was up to 5.8±0.7 ◦C warmer than preindustrial (PI). However, this benthic-based estimate is subject to uncertainties in seawater chemistry and is challenging to compare directly with surface temperature records. In this study, we synthesize benthic foraminiferal δ18O records with climate model simulations that feature an equilibrated deep ocean and include water isotope capability to better constrain the MCO warmth. Using a probabilistic inference framework, we estimate that the MCO GMST was most likely 8.0±0.8 ◦C warmer than PI, which is warmer than previous estimates and comparable to warming levels projected under the Shared Socioeconomic Pathway 5 (SSP8.5). In addition, our model-data-based framework provides a maximum likelihood estimation of the surface temperature field, which agrees well with independent surface proxies, thus offering a way to direct compare surface- and deep-ocean-based estimates. This study highlights the importance of equilibrated deep ocean conditions for more accurately estimating both deep ocean and surface temperatures, and our method can be applied to improve the reconstruction of global climate during other time intervals. Earth and environmental sciences/Climate sciences/Palaeoclimate Earth and environmental sciences/Climate sciences/Palaeoceanography Full Text Additional Declarations There is NO Competing Interest. Supplementary Files SI.pdf Supplementary Information for “Model-data synthesis of benthic isotopes suggests a warmer Miocene Climatic Optimum” Cite Share Download PDF Status: Under Review 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. 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-7124543","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":489226892,"identity":"dee42c64-6f49-4c64-bc08-d42550787e88","order_by":0,"name":"Feng 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Using a probabilistic inference framework, we estimate that the MCO GMST was most likely 8.0±0.8 ◦C warmer than PI, which is warmer than previous estimates and comparable to warming levels projected under the Shared Socioeconomic Pathway 5 (SSP8.5). In addition, our model-data-based framework provides a maximum likelihood estimation of the surface temperature field, which agrees well with independent surface proxies, thus offering a way to direct compare surface- and deep-ocean-based estimates. 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