DATE2022-06-22 17:09:51
TITLEWhat do past interglacials teach us about the response of climate of the Levant and the East Mediterranean to external forcing and to global climate variations?
AUTHORSYochanan Kushnir (1) ,Mordechi Stein (2) ,Yael Kiro (3) ,Steven L. Goldstein (1)
  1. 1) Lamont-doherty Earth Observatory/columbia University, Palisade, Ny (Usa) ,2) Institute Of Earth Sciences, The Hebrew University Of Jerusalem, Jerusalem (Israel) ,3) Department Of Earth And Planetary Sciences, The Weizmann Institute Of Science, Rehovot (Israel)
ABSTRACTThe Levant region, at the eastern margin of the Mediterranean Sea, has been subjected to periods of droughts and water scarcity throughout human history. This region is now undergoing a slow drying trend, together with the entire Mediterranean region, as the world warms due to increasing atmospheric greenhouse gas concentrations. A unique view of the historical and pre-historical climate of the Levant has been gleaned through the continued study of the sedimentary and geochemical records of the lakes that filled the tectonic basin of the Dead Sea. Here we revisit the sediment record retrieved during the 2010-2011 Dead Sea Deep Drilling Project. During interglacials lake levels were lower than during the adjacent glacial intervals, and thick deposits of salts accumulated at the Lake bottom, indicate significant regional aridity. In the previous interglacials, particularly during MIS 5e, around 125,000 years ago, during peak summer insolation, the conditions of regional aridity were interrupted by penetration of rains fed by tropical systems. This likely included that period intensified and more northward extended African summer monsoon. Evidence also exists that the normal winter wet period also intensified during peak summer insolation. The occurrence of summer rains was likely weaker or not present during the Holocene, which exhibited repeated severely dry intervals throughout the epoch. During the last interglacial, as summer insolation declined, and the African monsoon system contracted to its present-day state summer rains the Levant grew progressively drier and episodes of severe drying including evidence for a collapse of the winter rain regime occurred. This presentation will describe these findings in detail and their relation to the epochal insolation cycles, to the larger Mediterranean region and to global climatic variations in high and low latitudes, primarily in the Atlantic Ocean. We will discuss what these past connections imply for the projected greenhouse forced climate change.