Rapid atmospheric CO2 variations and ocean circulation

Abstract

Studies on air trapped in old polar ice1,2 have shown that during the last ice age, the atmospheric carbon dioxide concentration was probably significantly lower than during the Holocene—about 200 p.p.m. rather than 270 p.p.m. Also, Stauffer et al.3 recently showed by detailed analyses of Greenland ice cores, that during the ice age, between about 30,000 and 40,000 yr BP, the atmospheric CO2 level probably varied between 200 and 260 p.p.m. These variations occurred parallel to climatic variations as indicated by δ18O of the ice; astonishingly, the changes took place within rather short times, no more than a few centuries or even less. Here we examine the hypothesis4 that CO2 variations arose from changes in ocean circulation that affected the distribution of chemical properties and thus of P CO2 in the surface waters of the world ocean. Such changes can take place in a rather short time, in contrast to changes of whole ocean properties.