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13.06.2022: Ocean Circulation and Climate Dynamics Colloquium
Dr. Thomas Chalk, Centre européen de recherche et d'enseignement de géosciences de l'environnement (CEREGE), Aix-Marseille Université/CNRS/IRD/INRAE: "A(n almost) continuous 1,500 kyr record of atmospheric CO2 from boron isotopes"
When? Monday, 13. June 2022 at 11 am
Where? ZOOM meeting room: https://geomar-de.zoom.us/j/85359286971?pwd=bkRCYTI0WE9PSytvbzJQWXdlQWd6QT09
Meeting-ID: 853 5928 6971
Kenncode: 093073
During the past 1,500 thousand years (kyrs) Earth’s climate has undergone major changes, key among these being the Middle Pleistocene Transition (MPT). The MPT was a gradual change in the climate system that seemingly occurred without a significant change to external climate forcing, thus implicating internal climate feedbacks as the principal driver(s). Ice core CO2 data are only continuous for the last 800 kyrs meaning no high quality CO2 data covers this last great climate transition. To access information about the movement of carbon between the atmosphere and oceans through the MPT, reliable records of both atmospheric and oceanic carbon content are required. I will present a near continuous compilation of boron isotope-derived pH-CO2 records from low-latitude ocean sites over the past 1,500 kyrs, doubling the extent covered by high-resolution ice core records. I will show evidence for a close coupling of oceanic-pH and atmospheric CO2 over the ice core interval, confirming that the δ11B-pH proxy is well placed to extend the CO2 record beyond the reach of ice cores and validating our longer record. Combining CO2 with global temperature and sea level records, we can investigate changes to Earth System and Climate Sensitivities over the Pleistocene.
