Limiting warming by CO2 and methane mitigation in an expanded scenario space

Limiting warming by CO2 and methane mitigation in an expanded scenario space | 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 Limiting warming by CO 2 and methane mitigation in an expanded scenario space Konstantin Weber, Cyril Brunner, Lena Brun, Reto Knutti This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8863591/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 Anthropogenic methane (CH 4 ) is currently contributing over 0.5 °C to global warming, and mitigation of CH 4 emissions is a powerful option to limit warming in the near-term. However, assessments of the effect of greenhouse gas (GHG) mitigation rely on scenarios from Integrated Assessment Models (IAMs) that typically include highly non-linear emission trajectories due to economic optimization and assume similar mitigation ambition for CO 2 and CH 4 . Conversely, climate targets are often linear, with a primary focus on reducing CO 2 emissions. Here, we present a complementary approach for scenario generation to systematically map peak warming resulting from two main political choices: a linear reduction in CO 2 or GHG emissions to net zero by a certain year and the simultaneous change in CH 4 emissions. We show that without CH 4 mitigation, peak warming will inevitably exceed 1.7 °C (50% likelihood), and the likelihood of limiting warming to below 2 °C drops below 50% when net zero CO 2 emissions are achieved after 2050. Irrespective of the stringency of CH 4 mitigation, limiting warming to 1.5 °C is no longer plausible. We also show that a sustained linear reduction in CH 4 emissions by 10% (~35 MtCH 4 /year) until 2050 increases the 2 °C-compatible global remaining carbon budget by ~165 GtCO 2 . Our results emphasize both the immediate necessity and benefit of strong near-term CH 4 mitigation, and provide a basis for setting CH 4 mitigation targets compatible with different global temperature limits. Earth and environmental sciences/Climate sciences/Climate change/Climate-change mitigation Earth and environmental sciences/Climate sciences/Climate change Earth and environmental sciences/Climate sciences/Climate change/Climate and Earth system modelling Full Text Additional Declarations There is NO Competing Interest. Supplementary Files MethanepaperfirstdraftSI.pdf Supplementary Information 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-8863591","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":590368301,"identity":"3242f3b7-0edd-4e52-b966-1a0d6a291dea","order_by":0,"name":"Konstantin Weber","email":"data:image/png;base64,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","orcid":"https://orcid.org/0009-0003-5230-0283","institution":"ETH Zurich","correspondingAuthor":true,"prefix":"","firstName":"Konstantin","middleName":"","lastName":"Weber","suffix":""},{"id":590368302,"identity":"3a47c853-95f4-4c49-936c-f2e70739396a","order_by":1,"name":"Cyril Brunner","email":"","orcid":"https://orcid.org/0000-0001-8280-4253","institution":"ETH Zurich","correspondingAuthor":false,"prefix":"","firstName":"Cyril","middleName":"","lastName":"Brunner","suffix":""},{"id":590368303,"identity":"436722e8-0bc5-41ea-a27e-95eb70325525","order_by":2,"name":"Lena Brun","email":"","orcid":"","institution":"ETH Zurich","correspondingAuthor":false,"prefix":"","firstName":"Lena","middleName":"","lastName":"Brun","suffix":""},{"id":590368304,"identity":"9d13751b-2304-4f23-bf17-c3fe0b476773","order_by":3,"name":"Reto Knutti","email":"","orcid":"https://orcid.org/0000-0001-8303-6700","institution":"ETH Zurich","correspondingAuthor":false,"prefix":"","firstName":"Reto","middleName":"","lastName":"Knutti","suffix":""}],"badges":[],"createdAt":"2026-02-12 15:17:17","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8863591/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8863591/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":104402616,"identity":"e4790715-1190-4847-86e1-b75b26dbf256","added_by":"auto","created_at":"2026-03-11 12:15:55","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3561522,"visible":true,"origin":"","legend":"Article File","description":"","filename":"MethanepaperfirstdraftMAIN.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8863591/v1_covered_f0bb5eea-64d1-4aa0-b278-c761ded172a7.pdf"},{"id":102578629,"identity":"781cd86e-0a2f-4393-911e-1a98e9cb4b0a","added_by":"auto","created_at":"2026-02-13 08:46:47","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":247395,"visible":true,"origin":"","legend":"Supplementary Information","description":"","filename":"MethanepaperfirstdraftSI.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8863591/v1/f923c6071dff84407b4a625b.pdf"}],"financialInterests":"There is \u003cb\u003eNO\u003c/b\u003e Competing Interest.","formattedTitle":"Limiting warming by CO\u003csub\u003e2\u003c/sub\u003e and methane mitigation in an expanded scenario space","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-8863591/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8863591/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"Anthropogenic methane (CH\u003csub\u003e4\u003c/sub\u003e) is currently contributing over 0.5 °C to global warming, and mitigation of CH\u003csub\u003e4\u003c/sub\u003e emissions is a powerful option to limit warming in the near-term. 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We show that without CH\u003csub\u003e4\u003c/sub\u003e mitigation, peak warming will inevitably exceed 1.7 °C (50% likelihood), and the likelihood of limiting warming to below 2 °C drops below 50% when net zero CO\u003csub\u003e2\u003c/sub\u003e emissions are achieved after 2050. Irrespective of the stringency of CH\u003csub\u003e4\u003c/sub\u003e mitigation, limiting warming to 1.5 °C is no longer plausible. We also show that a sustained linear reduction in CH\u003csub\u003e4\u003c/sub\u003e emissions by 10% (~35 MtCH\u003csub\u003e4\u003c/sub\u003e/year) until 2050 increases the 2 °C-compatible global remaining carbon budget by ~165 GtCO\u003csub\u003e2\u003c/sub\u003e. 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