Interactions Between Climate Change and Human Activities During the Early to Mid-Holocene in the Eastern Mediterranean Basins
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Clim. Past, 12, 1847–1877, 2016 www.clim-past.net/12/1847/2016/ doi:10.5194/cp-12-1847-2016 © Author(s) 2016. CC Attribution 3.0 License. Interactions between climate change and human activities during the early to mid-Holocene in the eastern Mediterranean basins Jean-Francois Berger1, Laurent Lespez2, Catherine Kuzucuoglu˘ 3, Arthur Glais4, Fuad Hourani5, Adrien Barra6, and Jean Guilaine7 1Université de Lyon, CNRS, Université Lyon 2-Lumière, UMR 5600 EVS, 69007, France 2Université Paris Est Créteil (UPEC), UMR CNRS 8591 LGP, France 3Université Paris 1-Panthéon Sorbonne, UMR CNRS 8591 LGP, France 4Université Caen-Basse Normandie, UMR CNRS 6554 LETG-Caen, France 5University of Jordan, Faculty of Archaeology and Tourism, Amman, Jordan 6Université de Lyon, CNRS, Université Lyon 2-Lumière, UMR 5600 EVS, 69007, France 7Collége de France, Paris, France Correspondence to: Jean-Francois Berger ([email protected]) Received: 8 January 2016 – Published in Clim. Past Discuss.: 23 February 2016 Accepted: 24 June 2016 – Published: 12 September 2016 Abstract. This paper focuses on early Holocene rapid cli- 1 Introduction mate change (RCC) records in the Mediterranean zone, which are under-represented in continental archives (9.2 Expected to have had a large impact on past societies, rapid to 8.2 ka events) and on their impact on prehistoric soci- climate changes (RCCs), which start abruptly within one eties. This lack of data handicaps the general interpreta- decade or two at the most (in polar records) and most of- tion of climate impacts on human societies, which flourished ten concern a period of 150 to 400 years, are often consid- in recent years. Key questions remain about the impact of ered one of the main environmental factors causing socio- early Holocene cooling events on the Mediterranean climate, economic and cultural changes, migrations, and even col- ecosystems and human societies. In this paper, we discuss lapses (Weiss et al., 1993; Cullen et al., 2000; Staubwasser some examples from river and lake systems from the east- and Weiss, 2006; Weninger et al., 2006). According to this ern to central Mediterranean area (central Anatolia, Cyprus, climatic determinism, a RCC would be much harder (if not northeastern and northwestern Greece) that illustrate some impossible) for a human society to adapt to, thus leading to palaeohydrological and erosion variations that modified the radical societal transformations. In the course of this debate, sustainability of the first Neolithic populations in this region. recent and ongoing research on Neolithic societies points to Results allow us to present direct land–sea correlations and to the necessity to focus simultaneously on (i) the economic, reconstruct regional long-term trends as well as millennial- to socio-cultural, technological and cognitive transformations centennial-scale climatic changes. In this context, we ques- of the human group living on site(s); (ii) the sharpening of tion the socio-economic and geographical adaptation capac- old and new chronological series within the site(s); (iii) the ities of these societies (mobility, technology, economic prac- development of contextual analyses associated with geoar- tices, social organisation) during the “early Holocene” inter- chaeological researches; and (iv) investigating, with a high- val (11.7 to 8.2 ka), which corresponds partly to the Sapropel resolution and multi-proxy approach, the palaeoenvironmen- 1 deposition in the eastern Mediterranean sea. tal records available in the vicinity of Neolithic sites and their connections with the sites, an approach that is at present poorly utilised. Such an approach and methodology are in- deed the most appropriate for reconstructing and interpreting Published by Copernicus Publications on behalf of the European Geosciences Union. 1848 J. F. Berger et al.: Interactions between climate change and human activities the relationships between environmental and societal event Belfer-Cohen, 1989) and Anatolia (Özdogan,˘ 2011; Kuzu- records which have accompanied (or not) a rapid climate cuoglu,˘ 2014). This early Holocene phase was neverthe- change and to better estimate adaptability to changing en- less interspersed by several pluricentennial wetter/drier cli- vironments. As a matter of fact, a lack of a RCC signature in matic pulsations. Compared to today, the climate was then the climatic and environmental proxies studied in any sed- much more sensitive to freshwater forcing than to solar ac- iment record may have several meanings: an incorrect as- tivity (Teller and Livingston, 2002; Fletcher et al., 2013). sessment of a signal, an insufficient chronological control, For example, in the Greenland ice cores, three “rapid events” a disconnection between the locus studied and neighbouring (RCCs) caused by meltwater pulses are recorded at ca. 10.2, areas where sedimentary archives would be more favourable 9.2 and 8.2 ka, together with at least 11 other similar events for recording a rapid climate change, etc. These are the rea- documented for the entire early Holocene (Teller et al., 2002; sons why it is often suspected that the absence of signature of Fleitmann et al., 2008). In the eastern Mediterranean, exten- a RCC event in continental archives is more often due to the sion of the Siberian anticyclone to the eastern Mediterranean low temporal resolution of the available records rather than (regular influx of cold air masses) also played a major role the absence of the climatic signal on the local scale. This during the Holocene period. For example, cold air from the problematic situation is now increasingly addressed by new Siberian High (SH) extension created a rapid SST cooling results focusing on high-resolution analyses and chronolo- (Rohling et al., 2002) (Fig. 1). The multi-centennial variabil- gies, as well as on records linking both the archaeological ity in the GISP2 terrestrial potassium (KC), a proxy record- sites and their surrounding geomorphologic/environmental ing the strength and temporality of the SH (Mayewski et al., archives. In this paper, the goal is to highlight the variety of 1997), shows a stronger SH during some Holocene cold peri- occurrences of early Holocene RCC records using (i) inter- ods in the eastern Mediterranean, with repetitive impacts on connected water-related systems (rivers and wetlands) asso- the Anatolian/Aegean areas (Rohling et al., 2002; Weninger ciated with Neolithic sites in contrasting areas of the eastern et al., 2006, 2014). These latter authors identify a “RCC cor- Mediterranean Basin and (ii) the characteristics of the main ridor”, which runs from Ukraine, through southeastern Eu- morphogenic and hydrosedimentary responses to RCC on the rope, and into the Aegean and large parts of Anatolia and catchment or lacustro-palustrine scales. We present below the Levant, as well as onto the islands of Cyprus and Crete. four recently investigated continental fieldwork areas where Rogers (1997) linked cyclogenesis in the Mediterranean with new data have been acquired concerning the 9.5 to 7 ka time positive (strong) SH anomalies, while eastern Mediterranean span. These data are discussed in the context of their prox- flood activity shows periodically a positive relationship with imity to excavated archaeological sites or regional cultural an increasing trend in the KC proxy (Benito et al., 2015). trends on the regional scale (central Anatolia, Cyprus, eastern The potential impact of the 9.2 ka abrupt climatic event Macedonia, Corfu). Using different spatial scales, from the on human societies during the Neolithic “revolution” has site to the region and from the eastern to the central Mediter- rarely been explored (Borrell, 2007; Flohr et al., 2016), in ranean, the hydrogeomorphic and ecological impacts of these any case much less so than the 8.2 ka event. In this de- early Holocene RCCs are evaluated, along with their poten- bate, the effects of the worldwide “8.2” climatic event on the tial impacts on the first Neolithic societies. Mesolithic and Neolithic societies have been under discus- sion for a decade, with interpretations varying from abandon- ment of sites to collapse, and from large-scale migration to 2 The state of the art sustainability of occupation and social adaptation (for a com- plete overview, see Gehlen and Schön, 2005; Staubwasser During the first half of the Holocene, the eastern Mediter- and Weiss, 2006; Weninger et al., 2006, 2014; Berger and ranean regions experienced a climate regime significantly Guilaine, 2009; Flohr et al., 2016). Climatic records show wetter than today, coherently indicated by regional marine that the 8.2 ka event resulted in some of the most extreme and terrestrial isotopes (Bar-Matthews et al., 1997; Roberts environmental perturbations of the Holocene. For this rea- et al., 2008; Robinson et al., 2006), the Dead Sea level max- son, it has often been a subject in the literature since being imum (Migowski et al., 2006) and the Sapropel 1 formation first discussed (Alley et al., 1997). Extended over a time span period in the eastern Mediterranean Sea favoured by fresh- of 100–150 years in GISP2-GRIP polar archives (Thomas et water high runoff of tropical monsoonal origin (Rossignol- al., 2007), its duration has been found to be longer in nu- Strick, 1999; Rohling et al., 2015). During this period, merous marine and continental proxies (Fig. 1). In the east- changes in Mediterranean cyclogenesis would have been po- ern Mediterranean and other regions, the RCC interval be- tentially influenced by lower sea surface temperature (SST) tween 8.6 and 8.0 ka spans a longer time period than in the and evaporation (Brayshaw et al., 2011; Rohling et al., ice record, supporting the idea of an enhanced Siberian high- 2015). The general trend toward climate amelioration after pressure anticyclone over Asia (Rohling and Pälike, 2005; the Younger Dryas favoured the development and diffusion Weninger et al., 2014) controlling a global intensification of of agriculture from nuclear areas in the eastern Mediter- atmospheric circulation with cooler temperatures in polar re- ranean (Willcox et al., 2009), the Levant (Bar-Yosef and gions (Mayewski et al., 2004) and drier and cooler condi- Clim.