The Pliocene (5.33–2.58 Ma) was the last period in the Earth's history when atmospheric CO₂ concentrations were similar to today (~400 ppm) and global mean temperatures were significantly warmer. In the Mediterranean, the Pliocene, and more particularly the Piacenzian (3.6–2.58 Ma), has been intensively studied but less is known about the Early Pliocene climate. This study aims at filling this gap with a high-resolution alkenone-derived sea surface temperature (SST) record of the Zanclean epoch obtained from the composite Capo Rossello section (South Sicily). This new dataset is combined with the previously published records of Beltran et al. (2011), Herbert et al. (2015) and Herbert et al. (2018), to document SST changes during major regional and global oceanographic re-organizations such as the connection with the Atlantic basin. Our SST record highlights the key transition between the warm and unstable conditions during the Zanclean and the more stable and cooler Piacenzian, around 3.8 Ma ago. We suggest that this transition results from the intensification of the Mediterranean outflow and the establishment of the Northern Hemisphere glaciation. The combined effect of these mechanisms would be responsible for cooler, more seasonal and possibly dryer conditions in the Mediterranean.

上新世（5.33–2.58 Ma）是地球历史上最后一个大气层CO _{2的时期。}浓度与今天相似（〜400 ppm），全球平均温度明显升高。在地中海地区，对上新世，尤其是Piacenzian（3.6–2.58 Ma）进行了深入研究，但对上新世早期气候的了解较少。这项研究旨在利用高分辨率的烯酮衍生海面温度（SST）记录来弥补这一空白，该记录是从复合Capo Rossello剖面（南西西里）获得的Zanclean纪元。这个新的数据集与Beltran等人先前发布的记录相结合。（2011），Herbert等。（2015年）和赫伯特等人。（2018年），以记录在主要的区域和全球海洋学重组（例如与大西洋海盆的连接）期间海表温度的变化。我们的SST记录突出显示了Zanclean期间温暖和不稳定条件与3.8 Ma之前更稳定和凉爽的Piacenzian之间的关键过渡。我们建议，这种过渡是由于地中海外流加剧和北半球冰川形成的结果。这些机制的综合作用将导致地中海地区凉爽，季节性增加，甚至可能出现干燥情况。