Cold and Dry Outbreaks in the Eastern Mediterranean 3200 Years
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https://doi.org/10.1130/G46491.1 Manuscript received 13 May 2019 Revised manuscript received 17 July 2019 Manuscript accepted 17 July 2019 © 2019 Geological Society of America. For permission to copy, contact [email protected]. Published online XX Month 2019 Cold and dry outbreaks in the eastern Mediterranean 3200 years ago David Kaniewski1*, Nick Marriner2, Rachid Cheddadi3, Christophe Morhange4, Joachim Bretschneider5, Greta Jans6, Thierry Otto1, Frédéric Luce1, and Elise Van Campo1 1EcoLab, Université de Toulouse, CNRS, INP, UPS, 31062 Toulouse cedex 9, France 2 Laboratoire Chrono-Environnement UMR6249, Maison des sciences de l’homme et de l’environnement Claude Nicolas Ledoux USR 3124, CNRS, Université de Franche-Comté, UFR ST, 16 Route de Gray, 25030 Besançon, France 3Université Montpellier II, CNRS-UM2-IRD, ISEM, 34090 Montpellier, France 4Aix Marseille Université, CNRS, IRD, INRA, Collège de France, CEREGE, 13545 Aix en Provence, cedex 04, France 5Department of Archaeology–Ancient Near East, Faculty of Art and Philosophy, Ghent University, Sint-Pietersnieuwstraat 35, 9000 Gent, Belgium 6Near Eastern Studies, Faculteit Letteren, Katholieke Universiteit Leuven, Blijde-Inkomststraat 21, 3000 Leuven, Belgium ABSTRACT depict similar trends, evoking a severe climate Can climate affect societies? This question, of both past and present importance, is encap- shift of regional extent (Kaniewski et al., 2015). sulated by the major socioeconomic crisis that affected the Mediterranean 3200 yr ago. The Nonetheless, the quantifcation of changes in demise of the core civilizations of the Aegean and eastern Mediterranean during the Late rainfall regime and temperature has proved chal- Bronze Age and the early Iron Age (Dark Ages) is still controversial because it raises the ques- lenging until now, in part owing to the scarcity tion of climate-change impacts on ancient societies. Although evidence for this climate shift has of archives in Levantine coastal areas, where gradually gained currency, recent attempts to quantify its magnitude remain equivocal. Here social changes during the LBA crisis and the we focus on the northern Levant (coastal Syria) where the economic, political, and cultural Dark Ages were particularly acute. changes were particularly acute. We quantify past climate changes and fnd that mean annual Here, we used data from the southernmost temperatures attained anomalies of − 2.3 ± 0.3 °C to − 4.8 ± 0.4 °C compared to present-day part of the Kingdom of Ugarit (Syria), on the conditions. Rainfall regimes displayed an important shift in seasonality, with a 40% decrease alluvial plain and affuent valley of the Rumaili- in winter precipitation. A 300 yr period of dry and cool climate started ∼3200 yr ago and was ah River, near the present-day coastal town of coeval with deep social changes in the eastern Mediterranean. These “Little Ice Age”–type Jableh (Fig. 1), located west of the Jabal an conditions affected harvests, leading to severe food shortages that probably aggravated the Nuşayrīyah mountain range (Kaniewski et al., sociopolitical tensions. This crisis highlights the fragility of societies, both past and present, 2008, 2011a). The alluvial complex is over- to major climate-change episodes and their broader consequences. looked by Tell Tweini (Bretschneider and Jans, 2019). We used pollen-based assemblages to INTRODUCTION but the idea gradually lost currency because it quantify climate variables and probe climate More than fve decades ago, the American was not supported by any scientifc data. New and society during the LBA crisis–Dark Ages archaeologist Rhys Carpenter (1966) evoked a results from Tell Tweini in Syria (Fig. 1) have (Figs. 1–3). We compared the magnitude of this major climate shift ∼3200 yr ago to explain the recently revived Carpenter’s hypothesis. The site event with climate changes during the past two demise of the Mycenaean civilization. This cli- has provided evidence for a marked environmen- millennia (the Late Antiquity Little Ice Age dur- mate hypothesis was subsequently developed tal shift that is chronologically correlated with ing the Muslim Era, and the pre-industrial Little using the Palmer drought index (Weiss, 1982), the Late Bronze Age (LBA) crisis and the Dark Ice Age during the Ottoman Empire). winter climate and hemispheric circulation pat- Ages (we call the whole event “the crisis years” terns (Donlay, 1971; Bryson et al., 1974), and herein; Kaniewski et al., 2008). Since then, sev- METHODS historical climatology (Neumann and Parpola, eral records from Greece (Finné et al., 2017), Pollen Samples 1987; Alpert and Neumann, 1989). Debate at Cyprus (Kaniewski et al., 2013a), Syria (Sor- The pollen samples derive from two cores one point was heated (e.g., Neumann, 1985), rel and Mathis, 2016), Lebanon (Cheng et al., (termed TW-1 and TW-2; TW-1: 35°22′22.94″N, 2015), Israel (Litt et al., 2012; Kaniewski et al., 35°56′12.49″E, 17 m a.s.l. [above sea level]; 2013b, 2017; Langgut et al., 2013; Schiebel and TW-2: 35°22′13.16″N, 35°56′11.36″E, 16.06 m *E-mail: [email protected] Litt, 2018), and Egypt (Bernhardt et al., 2012) a.s.l.; Fig. DR1 in the GSA Data Repository1) 1GSA Data Repository item 2019333, Figures DR1–DR3 and Tables DR1–DR8, is available online at http://www.geosociety.org/datarepository/2019/, or on request from [email protected]. CITATION: Kaniewski, D., et al., 2019, Cold and dry outbreaks in the eastern Mediterranean 3200 years ago: Geology, v. 47, p. XXX–XXX, https://doi.org/10.1130/G46491.1 Geological Society of America | GEOLOGY | Volume XX | Number XX | www.gsapubs.org 1 Downloaded from https://pubs.geoscienceworld.org/gsa/geology/article-pdf/doi/10.1130/G46491.1/4813944/g46491.pdf by Natural Resources Canada Library-Ottawa user on 23 August 2019 Figure 1. Winter temper- composing that assemblage (Fig. DR3). Under ature and precipitation such a hypothesis, two plant species should not A reconstructions for Tell occur simultaneously in an assemblage if their Tweini, coastal Syria and comparison with other CRISIS YEARS overall climatic ranges do not intersect. We as- proxy records. (A) Map signed the fossil pollen taxa to modern species, Dark Ages Late Bronze Age crisis B 12 Coastal Syria, northern Levan showing location of Tell Mean winter temperature (°C) and subsequently calculated a weighted median Tweini and Jableh in the Euphrates 11 Tell Tweini Jableh 10 value and its standard deviations of the climate northern Levant. (B,C) 9 Warm range encompassed by all assigned modern spe- Winter temperature (with SYRIA 8 standard deviations) (B) 7 cies. Similar approaches have been used to infer Sea People event and winter precipitation C 6 past climate variables using the mutual climatic t 36 0 5 (with standard deviations) 34 0 4 range of insects (Elias, 1997), plant fossil re- (C) reconstructions for the 320 3 2 t mains (Mosbrugger and Utescher, 1997; Pross northern Levant. (D) Tem- 30 0 Wet peratures reconstructed 28 0 D et al., 2000), mollusks (Moine et al., 2002), and from Greenland Ice Sheet 260 Fall of Ugarit -26 ostracods (Horne, 2007) and to derive climate 240 -27 GISP2, Greenlan Project 2 (GISP2) record 220 T -28 emperature (°C) probability density functions (Kühl et al., 2002) (Kobashi et al., 2009); Winter precipitation (mm) 200 -29 from fossil pollen data. orange shading repre- Coastal Syria, northern Levan 180 -3 0 Our method (Cheddadi et al., 2017) also sents 1 standard deviation -3 1 t error. (E) Egypt’s Nile E -3 2 d accommodates the variability of pollen taxa in valley population (Butzer, 2.0 even -3 3 the fossil record by including a leave-one-out P. ) 1.8 CYCE -3 4 1976) (error bars denote n 1.6 calculation. For each fossil sample, one known the standard deviation of Egypt’s Nile valley 1.4 population taxon is removed and a weighted median (using each data point) drawn 1.2 4.2 kyr B. Populatio 1.0 the pollen percentages as a weight) of all of the with Egyptian chronol- Egypt (millions 0.8 ogy (Shaw, 2000) (Late 0.6 remaining taxa is calculated. For each sample, P.—Late Period; Third Int. Late P. Third Int. P. New Kingdom Egyptian chronology Troubled period we calculated the weighted median as many P.—Third Intermediate 4001600180010001200 40016002800 0002200 times as there are taxa in each fossil sample. Period). The Sea People YEAR (B.C.E.) “event” (Gilboa, 2006– The fnal climatic value is the median value of 2007; Killebrew and Lehmann, 2013) and the fall of the city of Ugarit (Syria; Yon, 2006) are all iterations. In addition, the standard deviation denoted as chronological bars. Crisis Years Cooling Event (CYCE) is shaded in blue. The other corresponds to the median value of all of the blue shaded bars denote periods of climate deterioration. standard deviations. The additional leave-one-out approach mini- retrieved with a percussion corer from the alluvi- Chronology mizes the effect of either over- or underrepre- al deposits (Rumailiah River and a small spring- The chronology is based on 10 accelera- sentation of some pollen species or those that fed valley) at the foot of Tell Tweini (Kaniewski tor mass spectrometry (AMS) 14C ages (Beta show large variations in the fossil record. The et al., 2008, 2010, 2011a, 2011b). We added Analytic [Miami, Florida, USA] and Poznan code was written using the software R (R Core eight new samples from the bottom of the core Laboratories [Poznan, Poland]). Full details are Team, 2014) and its various libraries (Akima and TW-2 (from 400 to 795 calibrated years Com- given in Table DR1 in the Data Repository. The Gebhardt, 2015), RMySQL (Ooms et al., 2016), mon Era [cal. yr CE]). Samples were prepared original age models are available in the litera- and the statistics that are part of the R software.