Detecting Anthropogenically Induced Changes in Extreme and Seasonal Evapotranspiration Observations

Detecting Anthropogenically Induced Changes in Extreme and Seasonal Evapotranspiration Observations | 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 Detecting Anthropogenically Induced Changes in Extreme and Seasonal Evapotranspiration Observations Marius Egli, Sebastian Sippel, Reto Knutti, Vincent Humphrey This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6521849/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 23 Jan, 2026 Read the published version in Nature Communications → Version 1 posted You are reading this latest preprint version Abstract Flash droughts are rapid-onset droughts that develop within days to a week. However, they are rarely studied through the lens of evapotranspiration (ET), the dominant flux driving changes in terrestrial water storage during such events. Here, we present a novel view on flash droughts by studying high ET extremes using both climate models and observational data. The identified high ET extremes are driven by periods with high incoming surface radiation and temperatures. Consistent with physical understanding these events are intensified by anthropogenic climate change. For the first time, we detect a robust change in extreme and seasonal ET in two observational datasets. Regionally, seasonal mean ET shows mixed increases and decreases from 1980 to 2023 depending on water supply and demand, while extreme ET universally increases due to increasing water demand. We expect regions with strong extreme ET trends to be at increased risk for flash droughts, as hydrological variability increases. Earth and environmental sciences/Climate sciences/Climate change/Attribution Earth and environmental sciences/Climate sciences/Climate change/Climate and Earth system modelling Earth and environmental sciences/Climate sciences/Hydrology Full Text Additional Declarations There is NO Competing Interest. Cite Share Download PDF Status: Published Journal Publication published 23 Jan, 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. 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-6521849","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":453877147,"identity":"6ebb12a2-601e-4a5b-a95a-b8d646641901","order_by":0,"name":"Marius Egli","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA/klEQVRIiWNgGAWjYJCCA2CSnbHxAYTPgxDEr4WZsdkAzGAjQgsEMDOwSRClRbf97MPDPH8Y5OSdmdsqPu44zMAv33v4A0PNHZxazM6kGxzmbWMwNjzM2HZz5pnDDJJtfAkGDMee4dZyII3hMG8DQ+LGZsa227xtaQwGx3gMEhgbDuPWcv4ZA8hh9SAtxX+BWuyBWg7g1XIDaAsPG0OCPDNjGxDZMBiw8Rg24NfyjOHg3DYJww3AQJbsbbPhkTiWY8yQcAyfw9KYP7z5YyMv397+8MPPNgk5/uYzxh8+1ODWAgUSDAYHICxwpDAkENIAAvINxKgaBaNgFIyCEQkAV4BSNJXWppEAAAAASUVORK5CYII=","orcid":"https://orcid.org/0000-0003-2399-9649","institution":"Institute for Atmospheric and Climate Science, ETH Zurich","correspondingAuthor":true,"prefix":"","firstName":"Marius","middleName":"","lastName":"Egli","suffix":""},{"id":453877148,"identity":"b397f5aa-87db-4687-87eb-d8d8294a25c3","order_by":1,"name":"Sebastian Sippel","email":"","orcid":"https://orcid.org/0000-0002-4510-4458","institution":"Leipzig University","correspondingAuthor":false,"prefix":"","firstName":"Sebastian","middleName":"","lastName":"Sippel","suffix":""},{"id":453877149,"identity":"f416de96-7047-4d12-a078-aaee7d9db43b","order_by":2,"name":"Reto Knutti","email":"","orcid":"https://orcid.org/0000-0001-8303-6700","institution":"ETH Zurich","correspondingAuthor":false,"prefix":"","firstName":"Reto","middleName":"","lastName":"Knutti","suffix":""},{"id":453877150,"identity":"be6e1714-1e12-456f-acb7-60de60c0386f","order_by":3,"name":"Vincent Humphrey","email":"","orcid":"","institution":"Federal Office of Meteorology and Climatology MeteoSwiss","correspondingAuthor":false,"prefix":"","firstName":"Vincent","middleName":"","lastName":"Humphrey","suffix":""}],"badges":[],"createdAt":"2025-04-24 14:52:13","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6521849/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6521849/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41467-025-67748-8","type":"published","date":"2026-01-23T05:00:00+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":101032600,"identity":"722b3d50-9eaf-49ea-b147-caf190895144","added_by":"auto","created_at":"2026-01-24 08:10:48","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4931576,"visible":true,"origin":"","legend":"Article File","description":"","filename":"extremeETmain.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6521849/v1_covered_3de7041d-a38a-4d23-91ed-053f8b4b0696.pdf"}],"financialInterests":"There is \u003cb\u003eNO\u003c/b\u003e Competing Interest.","formattedTitle":"Detecting Anthropogenically Induced Changes in Extreme and Seasonal Evapotranspiration Observations","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"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-6521849/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6521849/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"Flash droughts are rapid-onset droughts that develop within days to a week. 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