The sixth millennium before present (BP) was a period of profound climatic and environmental change, and a growing body of palaeoclimatic and palaeoenvironmental evidence suggests that the 6th millennium BP represents the last period of systematic global climatic reorganisation (Brooks, 2010). Throughout the northern hemisphere sub-tropics and adjacent regions, monsoon rainfall declined and collapsed, resulting in a shift from humid to arid conditions (Damnati, 2000; Guo et al., 2000; Brooks, 2006). In middle and high latitudes, and at high altitudes, cooling was associated with glacial advances (Magny et al., 2006; Thompson et al., 2006). Evidence from South America indicates the re-establishment of a regular El Niño after a long period of quiescence in the early part of the 6th millennium BP (Sandweiss et al., 2007). In the North Atlantic, the meridional overturning circulation was at its weakest since the climatic reversal of the Younger Dryas (McManus et al., 2004). Globally, there is growing evidence that this 6th millennium climatic transition was bracketed by episodes of abrupt climate change around 6000-5800 BP and 5300-5100 BP.
The 6th millennium was also a time of profound social change that saw the emergence of the world’s first cities and states in Egypt and Mesopotamia, and their precursors in many other world regions. In many parts of the world human societies became more complex and hierarchical against a backdrop of deteriorating environmental conditions and a decline in the availability and extent of key natural resources, such as water and grazing land (Brooks, 2006, 2010). Across the world, key periods of cultural transition coincided with periods of severe climatic and environmental change, particularly those centred around 5900 BP and 5200 BP (Brooks, 2010).
While the archaeological and palaeoenvironmental evidence strongly indicates that environmental changes played a key role in driving cultural changes in the 6th millennium BP some regions (such as Egypt and the Sahara), and is highly suggestive of links between environmental and cultural changes during this period in others (e.g. Mesopotamia, China and South Asia), more high-resolution studies are required to establish the extent to which key changes in human societies were mediated by environmental factors (Brooks, 2006, 2010). Crucially, more precise archaeological and environmental chronologies are needed, coupled with detailed studies of specific locations that can illuminate processes of change and mechanisms through which environmental changes may have influenced the development of human societies and communities.
The first workshop of the Environmental Change in Prehistory Network (ECPN) will review the existing archaeological and palaeoenvironmental data relating to the 6th millennium BP, focusing on the Mediterranean region (including the Levant and adjacent regions, North Africa and the Sahara, and southern and central Europe). The purpose of this workshop will be to establish the extent of and limits to such data, and to identify data gaps and needs, and opportunities for improving datasets. The workshop will address data that both support and conflict with hypotheses of climatically-mediated cultural changes in the 6th millennium BP.
This website and the 6th millennium forum provide further opportunities for exchanging news and ideas outside of and beyond the two planned workshops, through discussion boards (on the forum), comments (on posts on this website), and guests posts on this site.
Further information on the workshops and relating to the ECPN and its subject matter is available on this website (see the tabs at the top of this page) and linked sites (see the links on the right of this page).
Anyone interested in writing a guest post should contact Nick Brooks.
Brooks, N. 2010. Human responses to climatically-driven landscape change and resource scarcity: Learning from the past and planning for the future. In I. P. Martini and W. Chesworth (eds.) Landscapes and Societies: Selected Cases, pp. 43-66. Springer, Dordrecht, Heidelberg, London, New York, 478 pp.
Brooks N. 2006. Cultural responses to aridity in the Middle Holocene and increased social complexity. Quaternary International 151: 29–49.
Damnati B., 2000. Holocene lake records in the Northern Hemisphere of Africa. Journal of African Earth Sciences 31:253–26.
Guo Z., Petit-Maire, N., Kröpelin, S. 2000. Holocene non-orbital climatic events in present-day arid areas of northern Africa and China. Global and Planetary Change 26:97–103 175.
Magny, M., Leuzinger, U., Bortenschlager, S., et al. 2006. Tripartite climate reversal in Central Europe 5600–5300 years ago. Quaternary Research 65:3–1.
McManus, J. F., Francois, R., Gherardi, J-M., et al. 2004, Collapse and rapid resumption of Atlantic meridional circulation linked to deglacial climate changes. Nature 428:834–837.
Sandweiss, D. H., Maasch, K. A., Andrus, C. F. T., et al. 2007. Mid- Holocene climate and culture change in coastal Peru. In: Anderson DG, Maasch KA, Sandweiss DH. (eds) Climate
change and cultural dynamics: A global perspective on Mid- Holocene transitions. Academic Press, Elsevier, London, pp 25–50.
Thompson, D. P., van Hollen, D., Osborn, G., Ryane, C. 2006. Did neoglaciation begin as early as 6400 cal years ago? Geological Society of America Abstracts with Programs 38:236.