近年来观测数据显示，虽然大气CO2浓度持续快速上升，但是全球变暖趋势近乎停滞，地球气候系统中温度（水热循环）和大气CO2（碳循环）之间的内在联系仍存许多未知。上新世暖期（约3-5 Ma）是地质历史时期距今最近的一个持续性暖期，恢复该时期的海洋碳循环以及海水温度演化特征，有助于我们更好地预测未来气候的演变趋势。本项研究以南海北部大洋钻探U1501C站为研究对象，利用浮游有孔虫B/Ca、Mg/Ca指标方法，定量重建上新世暖期南海北部轨道尺度至千年尺度的上层海水pCO2、温度记录，并与晚第四纪相关记录（具有显著冰期-间冰期旋回特征）进行比较，尝试挖掘在不同气候背景下海水pCO2对于温度的响应机制，为预测全球变暖趋势下的未来气候变化提供线索。

In recent years, observation data reveal that although atmospheric CO2 concentration continues to rise rapidly, global warming trend nearly stopped. The internal relationship between temperature (hydro-thermal cycle) and atmospheric CO2 (carbon cycle) of the earth’s climate system is not completely understood. The Pliocene warm period (~3-5 Ma) is the most recent persistent long-term warm period in geological history. Reconstructions of marine carbon cycle and seawater temperature history will help us to better predict the evolution pattern of the future climate change. Based on the sediment core at IODP site U1501C from the northern South China Sea, our study intends to reconstruct the pCO2 and temperature records of surface-subsurface waters at the orbital to millennial time-scales by planktonic foraminiferal B/Ca and Mg/Ca, respectively. By comparing these records with those of the late Quaternary (characterized by typical glacial-interglacial cycle), our study tries to explore the response mechanisms of seawater pCO2 to temperature under different climate conditions and provide a clue for predicting the future climate change under the background of global warming.