{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,23]],"date-time":"2026-10-23T09:20:56Z","timestamp":1792747256449,"version":"4.5.0"},"reference-count":75,"publisher":"National Academy of Sciences","issue":"42","license":[{"start":{"date-parts":[[2022,10,10]],"date-time":"2022-10-10T00:00:00Z","timestamp":1665360000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"funder":[{"DOI":"10.13039\/100014155","name":"Heising-Simons Foundation","doi-asserted-by":"publisher","award":["2016-015"],"award-info":[{"award-number":["2016-015"]}],"id":[{"id":"10.13039\/100014155","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100014155","name":"Heising-Simons Foundation","doi-asserted-by":"publisher","award":["2016-012"],"award-info":[{"award-number":["2016-012"]}],"id":[{"id":"10.13039\/100014155","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100014155","name":"Heising-Simons Foundation","doi-asserted-by":"publisher","award":["2016-014"],"award-info":[{"award-number":["2016-014"]}],"id":[{"id":"10.13039\/100014155","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100014155","name":"Heising-Simons Foundation","doi-asserted-by":"publisher","award":["2016-011"],"award-info":[{"award-number":["2016-011"]}],"id":[{"id":"10.13039\/100014155","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100014155","name":"Heising-Simons Foundation","doi-asserted-by":"publisher","award":["2016-013"],"award-info":[{"award-number":["2016-013"]}],"id":[{"id":"10.13039\/100014155","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["www.pnas.org"],"crossmark-restriction":true},"short-container-title":["Proc. Natl. Acad. Sci. U.S.A."],"published-print":{"date-parts":[[2022,10,18]]},"abstract":"<jats:p>\n                    The Paleocene\u2013Eocene Thermal Maximum (PETM; 56 Ma) is one of our best geological analogs for understanding climate dynamics in a \u201cgreenhouse\u201d world. However, proxy data representing the event are only available from select marine and terrestrial sedimentary sequences that are unevenly distributed across Earth\u2019s surface, limiting our view of the spatial patterns of climate change. Here, we use paleoclimate data assimilation (DA) to combine climate model and proxy information and create a spatially complete reconstruction of the PETM and the climate state that precedes it (\u201cPETM-DA\u201d). Our data-constrained results support strong polar amplification, which in the absence of an extensive cryosphere, is related to temperature feedbacks and loss of seasonal snow on land. The response of the hydrological cycle to PETM warming consists of a narrowing of the Intertropical Convergence Zone, off-equatorial drying, and an intensification of seasonal monsoons and winter storm tracks. Many of these features are also seen in simulations of future climate change under increasing anthropogenic emissions. Since the PETM-DA yields a spatially complete estimate of surface air temperature, it yields a rigorous estimate of global mean temperature change (5.6\n                    <jats:sup>\u2218<\/jats:sup>\n                    C; 5.4\n                    <jats:sup>\u2218<\/jats:sup>\n                    C to 5.9\n                    <jats:sup>\u2218<\/jats:sup>\n                    C, 95% CI) that can be used to calculate equilibrium climate sensitivity (ECS). We find that PETM ECS was 6.5\n                    <jats:sup>\u2218<\/jats:sup>\n                    C (5.7\n                    <jats:sup>\u2218<\/jats:sup>\n                    C to 7.4\n                    <jats:sup>\u2218<\/jats:sup>\n                    C, 95% CI), which is much higher than the present-day range. This supports the view that climate sensitivity increases substantially when greenhouse gas concentrations are high.\n                  <\/jats:p>","DOI":"10.1073\/pnas.2205326119","type":"journal-article","created":{"date-parts":[[2022,10,10]],"date-time":"2022-10-10T15:18:59Z","timestamp":1665415139000},"update-policy":"https:\/\/doi.org\/10.1073\/pnas.cm10313","source":"Crossref","is-referenced-by-count":116,"title":["Spatial patterns of climate change across the Paleocene\u2013Eocene Thermal Maximum"],"prefix":"10.1073","volume":"119","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-9080-9289","authenticated-orcid":false,"given":"Jessica E.","family":"Tierney","sequence":"first","affiliation":[{"name":"Department of Geosciences, University of Arizona, Tucson, AZ 85721"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jiang","family":"Zhu","sequence":"additional","affiliation":[{"name":"Climate and Global Dynamics Laboratory, National Center for Atmospheric Research, Boulder, CO 80305"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5542-8106","authenticated-orcid":false,"given":"Mingsong","family":"Li","sequence":"additional","affiliation":[{"name":"Key Laboratory of Orogenic Belts and Crustal Evolution, Ministry of Education, School of Earth and Space Sciences, Peking University, Beijing 100871, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2333-0128","authenticated-orcid":false,"given":"Andy","family":"Ridgwell","sequence":"additional","affiliation":[{"name":"Department of Earth and Planetary Sciences, University of California, Riverside, CA 92521"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8486-9739","authenticated-orcid":false,"given":"Gregory J.","family":"Hakim","sequence":"additional","affiliation":[{"name":"Department of Atmospheric Sciences, University of Washington, Seattle, WA 98195"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5104-4271","authenticated-orcid":false,"given":"Christopher J.","family":"Poulsen","sequence":"additional","affiliation":[{"name":"Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2178-3476","authenticated-orcid":false,"given":"Ross D. M.","family":"Whiteford","sequence":"additional","affiliation":[{"name":"School of Earth and Environmental Sciences, University of St. Andrews, St. Andrews KY16 9AL, United Kingdom"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3904-2526","authenticated-orcid":false,"given":"James W. B.","family":"Rae","sequence":"additional","affiliation":[{"name":"School of Earth and Environmental Sciences, University of St. Andrews, St. Andrews KY16 9AL, United Kingdom"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lee R.","family":"Kump","sequence":"additional","affiliation":[{"name":"Department of Geosciences, Pennsylvania State University, University Park, PA 16802"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"341","published-online":{"date-parts":[[2022,10,10]]},"reference":[{"key":"e_1_3_4_1_2","doi-asserted-by":"publisher","DOI":"10.1146\/annurev-earth-040610-133431"},{"key":"e_1_3_4_2_2","doi-asserted-by":"publisher","DOI":"10.1098\/rsta.2017.0082"},{"key":"e_1_3_4_3_2","doi-asserted-by":"publisher","DOI":"10.1038\/nature23646"},{"key":"e_1_3_4_4_2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.2003197117"},{"key":"e_1_3_4_5_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.earscirev.2013.07.004"},{"key":"e_1_3_4_6_2","doi-asserted-by":"publisher","DOI":"10.1126\/sciadv.aax1874"},{"key":"e_1_3_4_7_2","doi-asserted-by":"publisher","DOI":"10.5194\/cp-16-1953-2020"},{"key":"e_1_3_4_8_2","doi-asserted-by":"publisher","DOI":"10.1126\/science.1109004"},{"key":"e_1_3_4_9_2","doi-asserted-by":"publisher","DOI":"10.1126\/science.aar8658"},{"key":"e_1_3_4_10_2","doi-asserted-by":"publisher","DOI":"10.1038\/nature05043"},{"key":"e_1_3_4_11_2","doi-asserted-by":"publisher","DOI":"10.1130\/G23261A.1"},{"key":"e_1_3_4_12_2","first-page":"114","article-title":"Hydrological and associated biogeochemical consequences of rapid global warming during the Paleocene-Eocene Thermal Maximum. Global Planet","volume":"157","author":"Carmichael M. J.","year":"2017","unstructured":"M. J. Carmichael , Hydrological and associated biogeochemical consequences of rapid global warming during the Paleocene-Eocene Thermal Maximum. Global Planet. Change 157, 114\u2013138 (2017).","journal-title":"Change"},{"key":"e_1_3_4_13_2","doi-asserted-by":"publisher","DOI":"10.1126\/science.aay3701"},{"key":"e_1_3_4_14_2","doi-asserted-by":"publisher","DOI":"10.5194\/gmd-12-3149-2019"},{"key":"e_1_3_4_15_2","doi-asserted-by":"publisher","DOI":"10.1126\/sciadv.1600891"},{"key":"e_1_3_4_16_2","doi-asserted-by":"publisher","DOI":"10.5194\/cp-17-203-2021"},{"key":"e_1_3_4_17_2","doi-asserted-by":"publisher","DOI":"10.5194\/gmd-7-2077-2014"},{"key":"e_1_3_4_18_2","doi-asserted-by":"publisher","DOI":"10.5194\/gmd-10-889-2017"},{"key":"e_1_3_4_19_2","doi-asserted-by":"publisher","DOI":"10.1175\/BAMS-D-12-00121.1"},{"key":"e_1_3_4_20_2","doi-asserted-by":"publisher","DOI":"10.1029\/2019MS001663"},{"key":"e_1_3_4_21_2","doi-asserted-by":"publisher","DOI":"10.1038\/s41586-020-2617-x"},{"key":"e_1_3_4_22_2","doi-asserted-by":"publisher","DOI":"10.1038\/s41586-021-03984-4"},{"key":"e_1_3_4_23_2","doi-asserted-by":"publisher","DOI":"10.1038\/37333"},{"key":"e_1_3_4_24_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0016-7037(99)00091-5"},{"key":"e_1_3_4_25_2","doi-asserted-by":"publisher","DOI":"10.1029\/2007GC001663"},{"key":"e_1_3_4_26_2","doi-asserted-by":"publisher","DOI":"10.1029\/2009PA001864"},{"key":"e_1_3_4_27_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.epsl.2011.12.042"},{"key":"e_1_3_4_28_2","doi-asserted-by":"publisher","DOI":"10.3389\/feart.2021.710036"},{"key":"e_1_3_4_29_2","doi-asserted-by":"publisher","DOI":"10.1130\/0091-7613(1994)022<0211:ASHEAT>2.3.CO;2"},{"key":"e_1_3_4_30_2","doi-asserted-by":"publisher","DOI":"10.1029\/2006PA001350"},{"key":"e_1_3_4_31_2","doi-asserted-by":"publisher","DOI":"10.1130\/G33567.1"},{"key":"e_1_3_4_32_2","doi-asserted-by":"publisher","DOI":"10.1130\/G38547.1"},{"key":"e_1_3_4_33_2","first-page":"139","article-title":"Arctic vegetation, temperature, and hydrology during Early Eocene transient global warming events. 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Working Group I Contribution to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change","author":"Forster P.","year":"2021","unstructured":"P. Forster , \u201cThe Earth\u2019s energy budget, climate feedbacks, and climate sensitivity\u201d in Climate Change 2021: The Physical Science Basis. Working Group I Contribution to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change, V. Masson-Delmotte et al., Eds. (Cambridge University Press, Cambridge, United Kingdom, 2021), pp. 923\u20131054."},{"key":"e_1_3_4_58_2","doi-asserted-by":"publisher","DOI":"10.1029\/2018PA003382"},{"key":"e_1_3_4_59_2","doi-asserted-by":"publisher","DOI":"10.1029\/2007GC001784"},{"key":"e_1_3_4_60_2","doi-asserted-by":"publisher","DOI":"10.1038\/ngeo755"},{"key":"e_1_3_4_61_2","doi-asserted-by":"publisher","DOI":"10.1038\/ngeo1179"},{"key":"e_1_3_4_62_2","doi-asserted-by":"publisher","DOI":"10.1038\/s41586-018-0272-2"},{"key":"e_1_3_4_63_2","doi-asserted-by":"publisher","DOI":"10.1038\/s41467-020-17887-x"},{"key":"e_1_3_4_64_2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.1303365110"},{"key":"e_1_3_4_65_2","doi-asserted-by":"publisher","DOI":"10.1038\/s41561-019-0310-1"},{"key":"e_1_3_4_66_2","doi-asserted-by":"publisher","DOI":"10.1175\/JCLI-D-19-0993.1"},{"key":"e_1_3_4_67_2","doi-asserted-by":"publisher","DOI":"10.1007\/s40641-019-00145-8"},{"key":"e_1_3_4_68_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.epsl.2020.116164"},{"key":"e_1_3_4_69_2","doi-asserted-by":"publisher","DOI":"10.1038\/ngeo1266"},{"key":"e_1_3_4_70_2","doi-asserted-by":"publisher","DOI":"10.1146\/annurev-earth-082420-063026"},{"key":"e_1_3_4_71_2","doi-asserted-by":"publisher","DOI":"10.1038\/nature17423"},{"key":"e_1_3_4_72_2","unstructured":"J. Tierney jesstierney\/petmDA: petmDA v1.0. Zenodo.https:\/\/zenodo.org\/record\/7096239. Deposited 20 September 2022."},{"key":"e_1_3_4_73_2","unstructured":"J. Tierney petmDA. GitHub. https:\/\/github.com\/jesstierney\/petmDA. Deposited 26 March 2022."},{"key":"e_1_3_4_74_2","unstructured":"J. King JonKing93\/DASH. GitHub. https:\/\/github.com\/JonKing93\/DASH. Deposited 11 March 2020."},{"key":"e_1_3_4_75_2","unstructured":"J. Tierney St-Andrews-Isotope-Geochemistry\/PETM_deltaCO2. GitHub. https:\/\/github.com\/St-Andrews-Isotope-Geochemistry\/PETM_deltaCO2. Deposited 26 March 2022."}],"container-title":["Proceedings of the National Academy of Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/pnas.org\/doi\/pdf\/10.1073\/pnas.2205326119","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,9,21]],"date-time":"2023-09-21T08:27:00Z","timestamp":1695284820000},"score":1,"resource":{"primary":{"URL":"https:\/\/pnas.org\/doi\/10.1073\/pnas.2205326119"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,10,10]]},"references-count":75,"journal-issue":{"issue":"42","published-print":{"date-parts":[[2022,10,18]]}},"alternative-id":["10.1073\/pnas.2205326119"],"URL":"https:\/\/doi.org\/10.1073\/pnas.2205326119","relation":{},"ISSN":["0027-8424","1091-6490"],"issn-type":[{"value":"0027-8424","type":"print"},{"value":"1091-6490","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,10,10]]},"assertion":[{"value":"2022-03-26","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2022-09-09","order":1,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2022-10-10","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}],"article-number":"e2205326119"}}