Climate cycles in the southern Levant and their global climatic connections

The history of Levant paleo-hydrology, which is expressed by the absolute water level record of the Dead Sea over the last 70 kyrs, has been shown to be closely coupled with global climate patterns, and specifically argued to be modulated by northern hemisphere climate systems. Here, this coupling is rigorously tested and the absolute lake level curve is compared with a variety of globally distributed climate archives and used to deconvolve the processes controlling regional climate and hydrology. Considering that different archives are based on different sampling resolutions, and hence might have inherently different recording sensitivities, each of the chosen archives was interpolated and then smoothed at varying temporal resolutions. The synthetic curves, ranging between temporal smoothing resolutions between 10 years and 15 kyrs were compared to the similarly processed lake level record over the last 60 kyrs. The best fit to the Dead Sea lake level was found to be with Antarctica temperatures and atmospheric CO₂ levels. Greenland temperatures and proximal archives such as the Soreq Cave and the Dead Sea lithological record, all yielded weaker correlations to the lake level curve. An exception to the strong correlation between Levant climate and atmospheric CO₂ concentrations, is observed during Marine Isotope Stage (MIS) 5e, at a time when the Dead Sea watershed was exposed to very weak Mediterranean westerly systems that imposed hyperarid conditions, and a superposition of southern derived systems that delivered short but intense precipitation to the region. At this time, Antarctic temperatures cross a temperature threshold beyond 1 °C above present. It is suggested that this exceptional warming phase induces a reorganization of global and regional climate systems influencing the Levant. These results have two important implications. The first is the understanding that global temperatures and atmospheric CO₂ concentrations impose the first order control over Levant climate. The second, is that the Antarctic records can be used as synthetic lake level proxies, extending the absolute lake level curve to ca. 800 ka, compared with its current span of 70 kyrs. Considering the importance of the Dead Sea lake level curve as a regional paleo-climatic-hydrologic recorder, the new synthetic curve provides a prominent proxy of Levant hydro-climate history.