Holocene Climate and Cultural Evolution in Late Prehistoric–Early Historic West Asia

TLDR

The eastern Mediterranean, West Asia, and the Indian subcontinent’s precipitation patterns are governed by subtropical upper‑ and middle‑tropospheric flow, shaping regional climate. The study aims to refine chronologies of paleoclimate and archaeology and develop transfer functions linking precipitation to agro‑production to clarify causal relationships. The authors synthesize Holocene climate change from proxy records across the region. Proxy evidence shows a weakened northern Indian monsoon, a strengthened southern monsoon, a long‑term drying trend in the eastern Mediterranean, and abrupt droughts at ~8200, 5200, and 4200 cal yr BP driven by altered subtropical flow, which radically changed precipitation vital for cereal agriculture and triggered observable social adaptations in West Asian archaeology.

Abstract

Abstract The precipitation climatology and the underlying climate mechanisms of the eastern Mediterranean, West Asia, and the Indian subcontinent are reviewed, with emphasis on upper and middle tropospheric flow in the subtropics and its steering of precipitation. Holocene climate change of the region is summarized from proxy records. The Indian monsoon weakened during the Holocene over its northernmost region, the Ganges and Indus catchments and the western Arabian Sea. Southern regions, the Indian Peninsula, do not show a reduction, but an increase of summer monsoon rain across the Holocene. The long-term trend towards drier conditions in the eastern Mediterranean can be linked to a regionally complex monsoon evolution. Abrupt climate change events, such as the widespread droughts around 8200, 5200 and 4200 cal yr BP, are suggested to be the result of altered subtropical upper-level flow over the eastern Mediterranean and Asia. The abrupt climate change events of the Holocene radically altered precipitation, fundamental for cereal agriculture, across the expanse of late prehistoric–early historic cultures known from the archaeological record in these regions. Social adaptations to reduced agro-production, in both dry-farming and irrigation agriculture regions, are visible in the archaeological record during each abrupt climate change event in West Asia. Chronological refinement, in both the paleoclimate and archaeological records, and transfer functions for both precipitation and agro-production are needed to understand precisely the evident causal linkages.