| Transfer functions applied to fossil pollen assemblages, paleoecological reconstruction from discriminant analyses, and isotope analyses were used to reconstruct the paleoclimate of the southern Levant (i.e., the region including modern Israel, Palestine and Jordan) in order to determine the rate and magnitude of climate change during the late Pleistocene, and the middle and late Holocene. These analyses, applied to stratified lake core sediments from the Dead Sea show an overall warming through the late Pleistocene (average annual temperature 17 degrees C). The middle Holocene demonstrates the greatest precipitation values (148mm annually), with annual temperatures averaging over 19 degrees C. The late Holocene shows continued summer warming, with winters cooling, and slightly decreased precipitation (128mm). Warmer summer and cooler winter temperatures produced a net result of relatively constant mean annual temperatures between the middle and late Holocene of 19 degrees C.;Transfer functions were generated from the correspondence of modern vegetation communities to modern temperatures and precipitation. Application of these transfer functions to reconstructed temperatures suggests strong short-term temperature fluctuations. Seasonal winter rainfall accounted for the majority of annual precipitation, with a minimal summer precipitation increases between the late Pleistocene and late Holocene. Additionally, July mean temperatures showed a steady increase of 3 degrees C from the late Pleistocene to late Holocene (increase from 23 to 26 degrees C), with mean January temperature warming 1.5 degrees from the late Pleistocene to nearly 11 degrees C during the middle Holocene followed by cooling to approximately 10 degrees C during the late Holocene.;Air mass temperatures inferred from changing Deuterium concentrations of fossil pollen demonstrate a modest increase of just over 3 degrees C through the late Pleistocene, from approximately 15 degrees C to just over 18 degrees C. The advent of sedentism in the Levant during the late Pleistocene benefited from a climatic optimum approximately 14,000 cal yr BP, allowing initial cultivation of cereal-type vegetation in the Dead Sea basin. |
