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A 23 m.y. record of low atmospheric CO (sub 2)

Ying Cui, Brian A. Schubert and A. Hope Jahren
A 23 m.y. record of low atmospheric CO (sub 2)
Geology (Boulder) (May 2020) Pre-Issue Publication


Current atmospheric CO2 concentration is known to be higher than it has been during the past approximately 800 k.y. of Earth history, based on direct measurement of CO2 within ice cores. A comparison to the more ancient past is complicated by a deficit of CO2 proxies that may be applied across very long spans of geologic time. Here, we present a new CO2 record across the past 23 m.y. of Earth history based on the delta 13C value of terrestrial C3 plant remains, using a method applicable to the entire approximately 400 m.y. history of C3 photosynthesis on land. Across the past 23 m.y., CO2 likely ranged between approximately 230 ppmv and 350 ppmv (68% confidence interval: approximately 170-540 ppm). CO2 was found to be highest during the early and middle Miocene and likely below present-day levels during the middle Pliocene (84th percentile: approximately 400 ppmv). These data suggest present-day CO2 (412 ppmv) exceeds the highest levels that Earth experienced at least since the Miocene, further highlighting the present-day disruption of long-established CO2 trends within Earth's atmosphere.

ISSN: 0091-7613
EISSN: 1943-2682
Serial Title: Geology (Boulder)
Serial Volume: Pre-Issue Publication
Title: A 23 m.y. record of low atmospheric CO (sub 2)
Affiliation: Montclair State University, Department of Earth and Environmental Studies, Montclair, NJ, United States
Published: 20200529
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 73
Accession Number: 2020-062907
Categories: StratigraphyGeneral geochemistry
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus.
Secondary Affiliation: University of Louisiana, USA, United StatesUniversity of Oslo, NOR, Norway
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2020, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 202018
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