Proxy-based studies have linked the pre-industrial atmospheric *p*CO₂ rise of ~20 ppmv in the mid-to late Holocene to an inferred increase in the Southern Ocean overturning and associated biogeochemical changes. However, the history of polar ocean overturning and ventilation through the Holocene remains poorly constrained. This study presents absolutely dated deep-sea coral radiocarbon records from the Drake Passage and Reykjanes Ridge, suggesting surprisingly invariant ventilation in Antarctic circumpolar waters and North Atlantic Deep Water. Findings indicate that long-term, large-scale polar ocean overturning wasn't responsible for millennial atmospheric *p*CO₂ evolution, suggesting instead that continuous nutrient and carbon redistribution within the water column and changes in land organic carbon stock regulated the atmospheric CO₂ budget.

Tianyu Chen, Laura F. Robinson, Tao Li, Andrea Burke, Xu Zhang, Joseph A. Stewart, Nicky J. White, Timothy D. J. Knowles