Toward a Cenozoic history of atmospheric CO 2 .
null nullBärbel HönischDana L RoyerDaniel O BreeckerPratigya J PolissarGabriel J BowenMichael J HenehanYing CuiJennifer C McElwainJennifer C McElwainMatthew J KohnAnn PearsonSamuel R PhelpsKevin T UnoAndrew RidgwellEleni AnagnostouJacqueline AustermannMarcus P S BadgerRichard S BarclayPeter K BijlThomas B ChalkChristopher R ScoteseElwyn de la VegaRobert M DeContoKelsey A DyezVicki FerriniPeter J FranksClaudia F GiuliviMarcus GutjahrDustin T HarperLaura L HaynesMatthew HuberKathryn E SnellBenjamin A KeislingWilfried KonradTim K LowensteinAlberto MalinvernoMaxence GuillermicLuz María MejíaJoseph N MilliganJohn J MortonLee NordtRoss D M WhitefordAnita Roth-NebelsickJeremy K Caves RugensteinMorgan F SchallerNathan D SheldonSindia SosdianElise B WilkesCaitlyn R WitkowskiYi Ge ZhangLloyd AndersonDavid J BeerlingClara T BoltonThure E CerlingJennifer M CottonJiawei DaDouglas D EkartGavin Lee FosterDavid R GreenwoodEthan G HylandElliot A JagnieckiJohn P JasperJennifer B KowalczykLutz KunzmannWolfram Michael KürschnerCharles E LawrenceCaroline H LearMiguel A Martínez-BotíDaniel P MaxbauerPaolo MontagnaB David A NaafsJames William Buchanan RaeMarkus RaitzschGregory J RetallackSimon J RingOsamu SekiJulio SepúlvedaAshish SinhaTekie F TesfamichaelAradhna TripatiJohan van der BurghJimin YuJames C ZachosLaiming ZhangPublished in: Science (New York, N.Y.) (2023)
The geological record encodes the relationship between climate and atmospheric carbon dioxide (CO 2 ) over long and short timescales, as well as potential drivers of evolutionary transitions. However, reconstructing CO 2 beyond direct measurements requires the use of paleoproxies and herein lies the challenge, as proxies differ in their assumptions, degree of understanding, and even reconstructed values. In this study, we critically evaluated, categorized, and integrated available proxies to create a high-fidelity and transparently constructed atmospheric CO 2 record spanning the past 66 million years. This newly constructed record provides clearer evidence for higher Earth system sensitivity in the past and for the role of CO 2 thresholds in biological and cryosphere evolution.