Response of atmospheric CO2 changes to the abyssal Pacific overturning during the last glacial cycle

Despite its critical role in regulating the global climate and carbon cycle, the evolution of Pacific abyssal circulation has not been fully deciphered during the last glacial cycle. Using the oxygenation and benthic δ¹³C gradient records, tracers that are sensitive to ocean circulation rates, we establish the abyssal Pacific overturning conditions since ~90 ka. Our results indicate that the intensity of abyssal Pacific overturning is closely related to atmospheric CO₂, with accelerated overturning during steps of CO₂ rise. Those depict a potential pathway of deep carbon dioxide into the atmosphere and highlight the critical roles of deep Pacific circulation in the global carbon cycle.