Tectonic degassing drove global temperature trends since 20 Ma

• Published in: Science
• Main Authors: Herbert, Timothy D., Dalton, Colleen A., Liu, Zhonghui, Salazar, Andrea, Si, Weimin, Wilson, Douglas S.
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Association for the Advancement of Science (AAAS) 2022
• Subjects: Ice Sheet
• Online Access: http://dx.doi.org/10.1126/science.abl4353; https://www.science.org/doi/pdf/10.1126/science.abl4353

The Miocene Climatic Optimum (MCO) from ~17 to 14 million years ago (Ma) represents an enigmatic reversal in Cenozoic cooling. A synthesis of marine paleotemperature records shows that the MCO was a local maximum in global sea surface temperature superimposed on a period from at least 19 Ma to 10 Ma, during which global temperatures were on the order of 10°C warmer than at present. Our high-resolution global reconstruction of ocean crustal production, a proxy for tectonic degassing of carbon, suggests that crustal production rates were ~35% higher than modern rates until ~14 Ma, when production began to decline steeply along with global temperatures. The magnitude and timing of the inferred changes in tectonic degassing can account for the majority of long-term ice sheet and global temperature evolution since 20 Ma.