Climate, history, and demography

A case-study from the Balikh Valley, Sy ria

Arne Wossink1

Introduction

Archaeologists have long debated the role of climate change in human history (Issar, Zohar 2004; Rosen 2007). One of the hotly debated issues is the hypothesis that a severe and abrupt drought at the end of the third millennium BC, the so-called 4.2 ka BP event, caused large-scale abandonment of settlements across the Near East and Eurasia (Weiss et al. 1993; most recently Staubwasser, Weiss 2006). The hypothesis that urban collapse in the Near East was partially or entirely the result of climate change has however remained controversial for the last 15 years (Akkermans, Schwartz 2003). Recent evidence from Tell Mozan and Tell Brak for example indicated that this disruption was perhaps less drastic than suggested earlier (Dohmann-Pfälzner, Pfälzner 2001; Oates D., Oates J. 2001). The present paper intends to (1) review the debate on the 4.2 ka BP event and its social consequences, (2) present evidence for localized adaptation responses using a demographic approach, and (3) look in detail at a case-study of human-environment relations to identify social mechanisms that can explain the observed changes in the archaeological record. To achieve these goals, this paper will draw on material derived from excavations and surveys in northern Mesopotamia (fig. 1).

The debate on the 4.2 ka BP event

Palaeoclimate proxy records show that Holocene climate was subject to considerable variation. The 4.2 ka BP event stands out as one of several globally recognized Holocene abrupt climate changes (Mayewski et al. 2004). For various reasons, however, the impact of the 4.2 ka BP event has remained controversial among archaeologists. The debate focuses on (1) the evidence for climate change, (2) the synchronicity of climate change and archaeologically observed material culture change, and (3) the relation between climate change and socio-cultural change. Several scholars consider the evidence for late third millennium BC climate change to be ambiguous and dismiss climate change on that basis. The causes of the 4.2 ka BP event are as yet uncertain (Staubwasser, Weiss 2006). The interpretation of the event ranges from a volcanic eruption, to prolonged drought, to a “ dust fallout event” resulting from a “ violent air blast that caused multi-site ignition and widespread wild‑fires”. Signals for such events are however rarely observed at archaeological sites, and their interpretation is disputed (Weiss et al. 1993; Courty 2001; Matthews 2003). Further, some climate proxy records, notably pollen records, do not document the 4.2 ka BP event (Gremmen, Bottema 1991).