Evidence for Limited Atmospheric CO 2 Rise at the Miocene Climatic Optimum

Journal article

Plain Language Summary: The Miocene Climatic Optimum (MCO), between about 17 and 15 million years ago, was a relatively warm period in Earth history. This warming was thought to originate from a rise in the CO2 concentration in the atmosphere that intensified the greenhouse effect. However, knowledge of CO2 concentrations across this time interval was not sufficient to test this hypothesis. We reconstruct atmospheric CO2 concentrations across this period by analyzing the chemistry of fossil remains of algae, which is CO2‐sensitive. This information shows that CO2 concentrations only rose by a modest amount when the MCO started.

Authors: Wubben, E; Frieling, J; Bats, YF; van Roij, L; de Haan, K

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Geophysical Union
• Journal: Paleoceanography and Paleoclimatology
• Volume: 41
• Issue: 6
• Article number: e2025PA005388
• Publication date: 2026-06-04
• Acceptance date: 2026-05-26
• DOI: 10.1029/2025pa005388
• EISSN: 2572-4525
• ISSN: 2572-4517
• Language: English
• Keywords: dinoflagellate cyst; Miocene; CO2; alkenone