Holocene Supra-Regional Environmental Changes as Trigger for Major Socio-Cultural Processes in Northeastern Africa and the Sahara

Abstract

This contribution presents the environmental changes that occurred over the last ten millennia in a vast region of North Africa, encompassing the Central Sahara, the Greater Nile Valley and the Horn of Africa. These areas are of particular significance in the continent because of the early socioeconomic transformations that occurred there. An up-to-date review of palaeoclimate research is proposed with the aim to highlight new theoretical approaches, analytical methods and innovative techniques. Results of recent research on high-resolution and well-dated palaeoenvironmental archives for proxy data have been used to understand the climatic variability at different scales of resolution. We trace the regional changes in Holocene palaeohydrology, mostly regulated by monsoonal precipitation, and their effects on the landscape, and highlight the occurrence of short-term climatic events, arid or humid that may have had disruptive consequences on human communities. The contribution also discusses the cultural dynamics that occurred in those regions because the latter were exploited by hunter/ gatherer groups from the onset of the Holocene until historical times. A reconstruction of patterns of human adjustment to climatic variability is here presented, focusing on key processes such as the origin of food production, social complexity and power, and the rise and fall of complex polities and interregional networks.Résumé Cette contribution présente les changements environnementaux survenus au cours des dix derniers millénaires dans une vaste région de l'Afrique du Nord, englobant le Sahara Central, la vallée du Nile, et la Corne de l'Afrique. Ces zones sont Afr Archaeol Rev (2015) 32:301-333 d'une importance particulière, car ce sont là que les processus de développement socio-économiques se sont initialement produits sur le continent. Une revue à jour de la recherche paléoclimatique est proposée dans le but de mettre en évidence de nouvelles approches théoriques, méthodes analytiques et techniques innovantes. Les résultats de recherches récentes sur des archives paléoenvironnementales à haute résolution et bien datées ont été utilisées pour comprendre la variabilité climatique à différentes échelles, traçant les changements régionaux dans la paléohydrologie de l'Holocène, principalement régis par les précipitations de mousson, et leurs effets sur le paysage et soulignant l'apparition de courts événements climatiques, aride ou humide, qui ont pu avoir des conséquences perturbatrices sur les communautés humaines. Cette contribution aborde également les dynamiques culturelles qui ont eu lieu dans ces régions depuis qu'elles ont été exploitées par des groupes de chasseurs/cueilleurs du début de l'Holocène aux périodes historiques. Une reconstruction des schémas d'adaptation humaine aux variations climatiques est présentée ici, en se concentrant sur des processus clés, tels que l'origine de la production alimentaire, la complexité sociale et le pouvoir; ainsi que sur l'essor et la chute de systèmes politiques complexes et de ...

Humans as Agents in the Termination of the African Humid Period

“…Correlation does not demonstrate causation, and it is possible that domesticated animal economies moved into shrub-transitioning environments in response to ecological shifts rather than causing such shifts. Indeed, this is the orthodox view of the relationship between climate changes and the spread of the Neolithic throughout subSaharan Africa (Smith, 1992;Marshall and Hildebrand, 2002;Kuper and Kröpelin, 2006;Ozainne, 2014;Wright, 2014;Gatto and Zerboni, 2015).…”

“…That FIGURE 4 | Locations of early occurrences of domesticated livestock in Africa. Data points were largely drawn from published archeological literature (e.g., Gifford-Gonzalez, 2005;Fuller et al, 2011;di Lernia, 2013;Linseele et al, 2014;Ozainne, 2014;Gatto and Zerboni, 2015). The 1000-year isochrone was digitized as contour lines from an ordinary kriged spherical semivariogram model (created in ArcGIS 10.1) of the distribution of early livestock occurrences.…”

“…Human communities likewise changed their settlement and subsistence practices, shifting from foraging to agriculture-dependent economies (Marshall and Hildebrand, 2002;Blanchet et al, 2015). The termination of the AHP is hypothesized to have spurred ecological conditions favorable for the rise of complex social systems in northern Africa and southwestern Asia in which irrigation systems, agricultural resources and food redistribution networks were managed by hierarchical leaders (Kuper and Kröpelin, 2006;Gatto and Zerboni, 2015).…”

Classifying past climate change in the Chew Bahir basin, southern Ethiopia, using recurrence quantification analysis

“…Donges et al, 2011;Kennett et al, 2012;Foerster et al, 2015Foerster et al, , 2016Trauth et al, 2015Trauth et al, , 2018. There is a general consensus amongst anthropologists that both long-term trends and severe, abrupt changes resulted in significant changes to the social and socio-economic behavior of early humans (Gatto and Zerboni, 2015;Clarke et al, 2016;Lahr, 2016;Flohr et al, 2016). The response to a changing habitat, both subtle or dramatic, accompanied by changes in essential resources such as food and water, could be either expansion, decease, migration, or adaption (e.g.…”

“…A well-studied example is provided by demographic reconstructions that have been made for the Saharan Holocene. These reconstructions show a temporal delay between the onset of humid conditions (based on sedimentary dust flux records) and human reoccupation of former desert areas, with associated societal changes seen as a response to the environmental changes (Manning and Timpson, 2014;Gatto and Zerboni, 2015;Clarke et al, 2016).…”