Sea level consequences of greenhouse gas emissions imply urgency of net negative emissions

Sea level consequences of greenhouse gas emissions imply urgency of net negative emissions | 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 Physical Sciences - Article Sea level consequences of greenhouse gas emissions imply urgency of net negative emissions Jan Zika, John Church This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9207136/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 Sea-level rise is one of the most impactful consequences of anthropogenic climate change. It results principally from thermal expansion of sea water and the transfer of mass from glaciers and ice sheets to the ocean 1 . Net-zero emissions of carbon dioxide, the dominant greenhouse gas, would likely stabilise surface temperatures at a level proportional to total emissions 2,3 . However, the immense inertia of the ocean 4 and cryosphere 5,6 mean global mean sea level (GMSL) will continue to rise for centuries to millennia 1,7,8 . Here, we demonstrate how past and future GMSL rise are related to a simple policy relevant metric: the product of how much carbon has been emitted and how long ago those emissions occurred, termed Carbon Air Time (CAT). Observations and GMSL projections 1,2 collapse onto the same GMSL versus CAT curve with each Tt of Carbon causing an ongoing 30 to 70 cm of rise per century. GMSL rises as CAT increases, even after net emissions are reduced to zero. Halting continued multi-century GMSL rise will require halting increases in CAT, only possible with negative emissions that reduce warming to near preindustrial levels. The Carbon Air Time model is a potentially valuable policy tool for estimating how future emissions drive sea level change, and for guiding mitigation goals, notwithstanding the possibility for abrupt ice-sheet collapse 1,9 . Earth and environmental sciences/Climate sciences/Climate change/Projection and prediction Earth and environmental sciences/Climate sciences/Climate change/Climate-change impacts/Governance Earth and environmental sciences/Climate sciences/Climate change/Climate-change mitigation Earth and environmental sciences/Climate sciences/Ocean sciences/Physical oceanography Full Text Additional Declarations There is NO Competing Interest. 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-9207136","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Physical Sciences - Article","associatedPublications":[],"authors":[{"id":616619034,"identity":"2bfcad01-9c1e-4cc3-90b5-f3c5cdc14ad4","order_by":0,"name":"Jan Zika","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA00lEQVRIiWNgGAWjYBAC9gb+BwcbGGygXDYitDA2MCQAtaSRqAWID5Om5eDBGTXnE7fznzFg+FB2mIF/RgIhLYwNBzccu524c0aOAeOMc4cZJG4Q1MLMcPAB2+3EDTd4NzDztgFdSFgLG1DLv3OJG86f3cD8F6hFnpAWwQYehoMb2w4kbjiQu4GZEajFgJAWaWaglpl9ycYbbuR/ONhzLp3H8MwD/Fr42Psff+z5Zie74fyxxAc/yqzl5I4TsIWBGYl9AIh5CKgfBaNgFIyCUUAMAADDPUye8wbSYAAAAABJRU5ErkJggg==","orcid":"https://orcid.org/0000-0003-3462-3559","institution":"UNSW Sydney","correspondingAuthor":true,"prefix":"","firstName":"Jan","middleName":"","lastName":"Zika","suffix":""},{"id":616619035,"identity":"7d9ab64d-14ed-478d-b7cf-a5026e75a25e","order_by":1,"name":"John Church","email":"","orcid":"https://orcid.org/0000-0002-7037-8194","institution":"University of New South Wales","correspondingAuthor":false,"prefix":"","firstName":"John","middleName":"","lastName":"Church","suffix":""}],"badges":[],"createdAt":"2026-03-24 05:50:08","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9207136/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9207136/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":106096934,"identity":"e46b2964-8882-4d21-bcd2-78f78b8a7bfe","added_by":"auto","created_at":"2026-04-03 11:57:17","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":906794,"visible":true,"origin":"","legend":"Article File","description":"","filename":"Sealevelconsequencesofgreenhousegasemissionsy2026m03d24.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9207136/v1_covered_a0e27982-1372-46ca-8350-3875bad5218b.pdf"}],"financialInterests":"There is \u003cb\u003eNO\u003c/b\u003e Competing Interest.","formattedTitle":"Sea level consequences of greenhouse gas emissions imply urgency of net negative emissions","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"nature-portfolio","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"","title":"Nature Portfolio","twitterHandle":"","acdcEnabled":false,"dfaEnabled":false,"editorialSystem":"ejp","reportingPortfolio":"","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-9207136/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9207136/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eSea-level rise is one of the most impactful consequences of anthropogenic climate change. 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