Southern Hemisphere and Deep-Sea Warming Led Deglacial Atmospheric CO2 Rise and Tropical Warming

Establishing what caused Earth's largest climatic changes in the past requires a precise knowledge of both the forcing and the regional responses. Here we establish the chronology of high and low latitude climate change at the last glacial termination by 14C dating benthic and planktonic foraminiferal stable isotope and Mg/Ca records from a marine core collected in the western tropical Pacific. Deep sea temperatures warmed by ~2oC between 19 and 17 ka B.P. (thousand years before present), leading the rise in atmospheric CO2 and tropical surface ocean warming by ~1000 years. The cause of this deglacial deep water warming does not lie within the tropics, nor can its early onset between 19-17 ka B.P. be attributed to CO2 forcing. Increasing austral spring insolation combined with sea-ice albedo feedbacks appear to be key factors responsible for this warming. 10.1126/science.1143791