Climatic variability in the Mediterranean region over the last 130 ka, sapropel formation and teleconnection with the North Atlantic and monsoon systems

• Main Authors: Sanchez Goñi, M. F., Fletcher, W. J., Landais, A.
• Other Authors: Laboratoire des Sciences du Climat et de l'Environnement (LSCE), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
• Format: Conference Object
• Language: English
• Published: HAL CCSD 2023
• Subjects: [SDU]Sciences of the Universe [physics]; Greenland; North Atlantic
• Online Access: https://hal.science/hal-04113739

International audience Since the identification of millennial-scale climatic variability in Greenland and the North Atlantic (Dansgaard-Oeschger (D-O) and Heinrich (H) events) several questions remain open regarding the expression of this variability in the Mediterranean region, the oceanic and atmospheric mechanisms involved and how other forcings such as orbital parameters affect this variability. Several high-resolution pollen-rich marine cores retrieved in the framework of the IMAGES and ODP programs and covering at least the last 50,000 years have been analysed in the last decade. An array of terrestrial and marine micropalaeontological (pollen, foraminifer), sedimentary (microcharcoal, ice rafted detritus) and geochemical (d18O and d13C) tracers from the same sample set has allowed us to establish a direct correlation between the evolution of the atmospheric and oceanic reservoirs. All the D-O events have a counterpart in western Mediterranean terrestrial and marine ecosystems. Cold sea surface temperatures (SST) were synchronous with the expansion of semi-desert landscapes indicating a decrease in winter precipitation likely related with the northward displacement of the westerlies. SST increases were contemporaneous with the expansion of this forest and, therefore, the establishment of the Mediterranean climate, i.e. wet and mild winters with warm and dry summers. The best expression of the Mediterranean climate occurred during the Eemian, D-O 24, 21, 17-16, 8-7, 1 and the Holocene. These maxima occurred always during precession minima (seasonality maxima). The comparison of Mediterranean and Atlantic terrestrial and marine palaeoclimatic records of the last glacial period with Greenland temperature changes reveals that the Mediterranean region is distinctly impacted by precession. The comparison of this contrasting latitudinal climatic scenario with the global methane record which is also modulated by precession during the last climatic cycle reveals that the amplitude of methane peaks parallels the ...