The polar ocean and glacial cycles in atmospheric CO₂ concentration

Global climate and the atmospheric partial pressure of carbon dioxide (p_co2^atm) are correlated over recent glacial cycles, with lower p_co2^atm during ice ages, but the causes of the p_co2^atm changes are unknown. The modern Southern Ocean releases deeply sequestered CO₂ to the atmosphere. Growing evidence suggests that the Southern Ocean CO₂ leak was stemmed during ice ages, increasing ocean CO₂ storage. Such a change would also have made the global ocean more alkaline, driving additional ocean CO₂ uptake. This explanation for lower ice-age p_co2^atm, if correct, has much to teach us about the controls on current ocean processes.