The 4.2 ka BP climatic event and its cultural responses

Abstract

The 4.2 ka event was one of Holocene abrupt-change events and characterized by dry and cool climatic conditions in many parts of the world. The event was reported to have played important roles in the collapses of those major ancient civilizations. This paper first attempts to portray a global picture of this “4.2 ka Event” and then reviews those reliably-dated sequences containing “4.2 ka Event” retrieved from the domains of four major civilizations. This review further confirms the proposition advocated by the International Stratigraphy Committee that 4.2 ka was the chronological divider between the warmer-wetter middle Holocene and the cooler-drier late Holocene. This review also lends a further support to early proposals that the declines or disruptions of Ancient Egyptian Culture, Mesopotamian Culture, and Ancient Indian Culture at ∼4.2 ka BP were directly or indirectly associated with the “4.2 ka Event”. In Chinese cultural domain, the derailment of nearly all of the well-developed Neolithic cultures at ∼4.2 ka BP was also chronologically correlated with the proxy data-recorded abrupt climatic change at ∼4.2 ka BP. But, it should be admitted that either drying or cooling or drying and cooling at ∼4.2 ka BP might not be sufficient to collapse these well-developed cultures in presently warm and wet southern China. Surely, further studies are needed for constraining the climatic and environmental variables at ∼4.2 ka BP not only in southern China but also in the adjacent Central Plains of China.