The Southern Ocean plays a prominent role in the Earth's climate and carbon cycle. Changes in the Southern Ocean circulation may have regulated the release of CO 2 to the atmosphere from a deep-ocean reservoir during the last deglaciation. However, the path and exact timing of this deglacial CO 2 release are still under debate. Here we present measurements of deglacial surface reservoir 14 C age changes in the eastern Pacific sector of the Southern Ocean, obtained by 14 C dating of tephra deposited over the marine and terrestrial regions. These results, along with records of foraminifera benthic-planktic 14 C age and δ 13 C difference, provide evidence for three periods of enhanced upwelling in the Southern Ocean during the last deglaciation, supporting the hypothesis that Southern Ocean upwelling contributed to the deglacial rise in atmospheric CO 2. These independently dated marine records suggest synchronous changes in the Southern Ocean circulation and Antarctic climate during the last deglaciation. © 2013 Macmillan Publishers Limited. All rights reserved.