Dr. Emmanuel Guillerm
Affiliated Postdoctoral researcher
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Dr. Emmanuel Guillerm is currently a postdoctoral researcher at the GFZ in Potsdam (Germany) He was an Azrieli Postdoctoral Fellow at the lab during 2022-2023. He conducts research in the field of paleoclimatology and paleoenvironments. His work focuses on saline lakes and their sedimentary salt deposits throughout the geological record. Using a wide range of experimental and numerical modelling methods, Emmanuel harnesses these salt deposits and lake water archives to produce quantitative reconstructions of past climate variables (temperature, river discharge, etc.) which are then used to better grasp the evolution of atmospheric and oceanic circulations throughout geological times. By increasing knowledge on the evolution of past climate and its causes, Emmanuel hopes to contribute to a more accurate prediction of the climatic consequences of human activities. His research project at the PetroLab focuses on the climate of the Dead Sea over the last 200,000 years.
Emmanuel was born in Brest, France. After graduating from the École Nationale Supérieure de Géologie (ENSG), he spent a sabbatical in the French Alps where he roamed the mountains, increased his knowledge of flora and fauna, and worked as a guide and activity leader in a natural history museum to convey his concern and passion for nature to young and old. He completed his PhD at the Université de Lyon under the direction of geologist Dr. Véronique Gardien and physicist Prof. Frédéric Caupin. Emmanuel shares his passion for nature and physical and social sciences with his partner, with whom he often discusses their latest read over a glass of good wine. Together they love hiking and bird-watching.
He also sings and plays the guitar.
Current Research
Current Research
Dead Sea temperature and hydrology during the Last Interglacial witness insolation-paced westerly winds in the Northern Hemisphere
Wintertime westerlies are a key climatic driver in the extratropical Northern Hemisphere. They have strengthened and shifted north throughout the last six decades, amplifying the impacts of global warming in terms of drought, temperature increase and storminess. This recent trend remains unmatched by climate models. Thus, understanding what controlled wintertime westerlies over the geological past is key to predict their evolution, but currently suffers from the scarcity of reliable archives of winter temperature and rainfall. In the current project, Manu aims to reconstruct winter climate variables during the Last Interglacial (LIG, ~130-115 ka BP) in the Dead Sea, based on speed of sound in fluid inclusions in halite crystals. Initial results show that wintertime westerlies appear to have been driven by the latitudinal temperature gradients of air and sea surface, controlled by winter and autumn insolations, respectively. They exceeded modern strength and latitude soon after the LIG onset, culminated around 120 ka BP, before a fast weakening and southward retreat. This atmospheric mechanism, which resembles an orbital-scale North Atlantic Oscillation (NAO), solves major inconsistencies in the narrative of the LIG. It explains excess warmth in northern Eurasia, the persistent interglacial conditions in Southern Europe, the late advection of Atlantic warm waters to the eastern North Atlantic and Nordic Seas as opposed to the northwest North Atlantic, the minimum ice sheet volume occurring ~6 millennia later in Greenland compared with Antarctica, and the fast waxing of Eurasian ice sheets out of phase with summer insolation.
Map showing the Azores High (H), the Icelandic Low (L), their associated air circulation (small arrows), and the westerlies when strong and weak (solid and dashed large arrow, respectively). Black rectangle in a enlarged in b, showing the Dead Sea and its watershed (pale blue area). Regional rainfall contours in mm yr-1. c, Alternations of coarse (bh) and cumulate fine (cc) halite crystals from depth 257.8 meter below lake floor in core 5017-1-A. d, FIs in bottom-growth coarse halite from core 5017-1-A. Brillouin thermometry is based on the comparison of speed of sound in the monophasic (e) and biphasic (f) FI.
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