{"NOAAStudyId":"24290","contactInfo":{"address":"325 Broadway, E/NE31","city":"Boulder","constraints":"Please cite original publication, online resource, dataset and publication DOIs (where available), and date accessed when using downloaded data. If there is no publication information, please cite investigator, title, online resource, and date accessed. The appearance of external links associated with a dataset does not constitute endorsement by the Department of Commerce/National Oceanic and Atmospheric Administration of external Web sites or the information, products or services contained therein. For other than authorized activities, the Department of Commerce/NOAA does not exercise any editorial control over the information you may find at these locations. These links are provided consistent with the stated purpose of this Department of Commerce/NOAA Web site.","country":"USA","dataCenterUrl":"https://www.ncdc.noaa.gov/data-access/paleoclimatology-data","email":"paleo@noaa.gov","fax":"303-497-6513","longName":"National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce ","phone":"303-497-6280","postalCode":"80305-3328","shortName":"DOC/NOAA/NESDIS/NCEI","state":"CO","type":"CONTACT INFORMATION"},"contributionDate":"2018-05-27","dataPublisher":"NOAA","dataType":"CLIMATE FORCING","dataTypeInformation":"https://www.ncdc.noaa.gov/data-access/paleoclimatology-data/datasets/climate-forcing","difMetadataLink":"http://www1.ncdc.noaa.gov/pub/data/metadata/published/paleo/dif/xml/noaa-forcing-24290.xml","doi":null,"earliestYearBP":63000000,"earliestYearCE":-62998050,"entryId":"noaa-forcing-24290","funding":[{"fundingAgency":"US Department of Energy","fundingGrant":"DE-FG02-13ER16412"}],"investigators":"Cui, Y.; Schubert, B.A.","mostRecentYearBP":52980000,"mostRecentYearCE":-52978050,"onlineResourceLink":"https://www.ncdc.noaa.gov/paleo/study/24290","originalSource":null,"publication":[{"abstract":"Knowledge of the past concentrations of atmospheric CO2 level (pCO2) is critical to understanding climate sensitivity to changing pCO2. Towards this, a new proxy for pCO2 has been developed based on changes in carbon isotope fractionation (D13C) in C3 land plants. The accuracy of this approach has been validated against ice-core pCO2 records, suggesting the potential to apply this proxy to other geological periods; however, no thorough uncertainty assessment of the proxy has been conducted. Here, we first analyze the uncertainty in the model-curve fit through the experimental data using a bootstrap approach. Then, errors of the five input parameters for the proxy are evaluated using sensitivity analysis; these include the carbon isotope composition of atmospheric CO2 (d13CCO2) and that of the plant material (d13Corg) for two time periods, a reference time (t = 0) and the time period of interest (t), and the value of pCO2 at time t = 0. We then propagated the errors on the reconstructed pCO2 using a Monte Carlo random sampling approach that combined the uncertainties of the curve fitting and the five inputs for a scenario in which the reference time was the Holocene with a target period for the reconstructed pCO2 during the Cenozoic. We find that the error in the reconstructed pCO2(t) increases with increasing pCO2(t), yet remains <122% (positive error) and <40% (negative error) for pCO2(t) < 1000 ppmv. The error assessment suggests that it can be used with confidence for much of the Cenozoic and perhaps the majority of the last 400 million years, which is characterized by pCO2 levels generally less than 1000 ppmv. Towards this, an application of this uncertainty analysis is presented for the Paleogene (52-63 Ma) using published data. The resulting pCO2(t) levels calculated using this method average 470 +288/-147 ppmv (1sigma, n = 75), and overlap with previous pCO2(t) estimates determined for this time period using stomata, liverwort, and paleosol proxies. The analysis presented here assumes that the paleoenvironment in which the plants grew is unknown and is determined to be the largest source of error in the reconstructed pCO2(t) levels; errors in pCO2(t) could be reduced provided independent determination of the paleoenvironmental conditions at the fossil site.","author":{"name":"Ying Cui, Brian A. Schubert"},"citation":"Ying Cui, Brian A. Schubert. 2016. Quantifying uncertainty of past pCO2 determined from changes in C3 plant carbon isotope fractionation. Geochimica et Cosmochimica Acta, 172, 127-138. doi: 10.1016/j.gca.2015.09.032","edition":null,"identifier":{"id":"10.1016/j.gca.2015.09.032","type":"doi","url":"http://dx.doi.org/10.1016/j.gca.2015.09.032"},"issue":null,"journal":"Geochimica et Cosmochimica Acta","pages":"127-138","pubRank":"1","pubYear":2016,"reportNumber":null,"title":"Quantifying uncertainty of past pCO2 determined from changes in C3 plant carbon isotope fractionation","type":"publication","volume":"172"}],"reconstruction":"N","scienceKeywords":null,"site":[{"NOAASiteId":"22723","geo":{"geoType":"Feature","geometry":{"coordinates":["-90","90","-180","180"],"type":"POLYGON"},"properties":{"easternmostLongitude":"180","maxElevationMeters":null,"minElevationMeters":null,"northernmostLatitude":"90","southernmostLatitude":"-90","westernmostLongitude":"-180"}},"locationName":"Geographic Region>Global","mappable":"N","paleoData":[{"NOAADataTableId":"35973","coreLengthMeters":null,"dataFile":[{"NOAAKeywords":["earth science>paleoclimate>climate forcing>carbon dioxide"],"fileUrl":"https://www1.ncdc.noaa.gov/pub/data/paleo/climate_forcing/trace_gases/Paleo-pCO2/cui2016c3.txt","linkText":"Paleogene C3 Plants pCO2 Calibration Data","urlDescription":"NOAA Template File","variables":[{"cvAdditionalInfo":null,"cvDataType":"CLIMATE FORCING","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"million years ago","cvWhat":"age variable>age"},{"cvAdditionalInfo":"from d13C organic matter","cvDataType":"CLIMATE FORCING","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":"atmospheric material>bulk atmosphere","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"parts per million","cvWhat":"chemical composition>compound>inorganic compound>carbon dioxide"}]},{"NOAAKeywords":["earth science>paleoclimate>climate forcing>carbon dioxide"],"fileUrl":"https://www1.ncdc.noaa.gov/pub/data/paleo/climate_forcing/trace_gases/Paleo-pCO2/cui2016c3.xlsx","linkText":"Paleogene C3 Plants pCO2 Calibration Data","urlDescription":"Excel File","variables":[]}],"dataTableName":"Cui2016C3","dataTableNotes":null,"earliestYear":63000000,"earliestYearBP":63000000,"earliestYearCE":-62998050,"mostRecentYear":52980000,"mostRecentYearBP":52980000,"mostRecentYearCE":-52978050,"species":[],"timeUnit":"cal yr BP"}],"siteName":"Global"}],"studyCode":null,"studyName":"Paleo-pCO2 Database Paleogene C3 Plants pCO2 Calibration Data","studyNotes":"Calibration of Paleo-CO2 estimation from Paleogene C3 plants, contributed to the Paleo-pCO2 Database","version":"1.0","xmlId":"22434"}