NOAA/WDS Paleoclimatology - Western Tropical Pacific, 21Kyr BP to present, Foraminiferal Stable Isotope, Mg/Ca and SST Data

Establishing what caused Earth's largest climatic changes in the past requires a precise knowledge of both the forcing and the regional responses. We determined the chronology of high- and low-latitude climate change at the last glacial termination by radiocarbon dating benthic and planktonic foraminiferal stable isotope and magnesium/calcium records from a marine core collected in the western tropical Pacific. Deep-sea temperatures warmed by ~2°C between 19 and 17 thousand years before the present (ky B.P.), leading the rise in atmospheric CO2 and tropicalŋsurface-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 and 17 ky B.P. be attributed to CO2 forcing. Increasing austral-spring insolation combined with sea-ice albedo feedbacks appear to be the key factors responsible for this warming.

厘清地球过去重大气候变迁的成因，需精准掌握气候强迫（forcing）机制与区域气候响应特征。本研究通过对热带西太平洋海域获取的一根海洋岩芯中的底栖与浮游有孔虫稳定同位素、镁钙比记录进行放射性碳定年，确立了末次冰消期高低纬度气候变化的年代序列。深海温度在距今19至17千年（ky B.P.）间上升了约2℃，较大气CO₂浓度升高与热带表层海洋升温早约1000年。此次冰消期深海升温的成因并非源自热带区域，且其在距今19至17千年间的早期启动也无法归因于CO₂强迫。南半球春季太阳辐射增强与海冰反照率反馈的共同作用，似乎是此次升温的关键驱动因素。