4.2-kiloyear event

Global distribution of the 4.2 kiloyear event. The hatched areas were affected by wet conditions or flooding, and the dotted areas by drought or dust storms.[1]

The 4.2-kiloyear (thousand years) BP aridification event (long-term drought), also known as the 4.2 ka event,[2] was one of the most severe climatic events of the Holocene epoch.[3] It defines the beginning of the current Meghalayan age in the Holocene epoch.

Starting around 2200 BC, it most likely lasted the entire 22nd century BC. It has been hypothesised to have caused the collapse of the Old Kingdom in Egypt, the Akkadian Empire in Mesopotamia, and the Liangzhu culture in the lower Yangtze River area.[4][5] The drought may also have initiated the collapse of the Indus Valley Civilisation, with some of its population moving southeastward to follow the movement of their desired habitat,[6] as well as the migration of Indo-European-speaking people into India.[7] Some scientists disagree with that conclusion, citing evidence that the event was not a global drought and did not happen in a clear timeline.[8]

  1. ^ Another map for reference in Railsback, L. Bruce; Liang, Fuyuan; Brook, G. A.; Voarintsoa, Ny Riavo G.; Sletten, Hillary R.; Marais, Eugene; Hardt, Ben; Cheng, Hai; Edwards, R. Lawrence (15 April 2018). "The timing, two-pulsed nature, and variable climatic expression of the 4.2 ka event: A review and new high-resolution stalagmite data from Namibia". Quaternary Science Reviews. 186: 78–90. Bibcode:2018QSRv..186...78R. doi:10.1016/j.quascirev.2018.02.015. ISSN 0277-3791. The initial source where this map comes from had the map caption the wrong way around: Wang, Xinming; Wang, Yuhong; Chen, Liqi; Sun, Liguang; Wang, Jianjun (10 June 2016). "The abrupt climate change near 4,400 yr BP on the cultural transition in Yuchisi, China and its global linkage". Scientific Reports. 6: 27723. Bibcode:2016NatSR...627723W. doi:10.1038/srep27723. ISSN 2045-2322. PMC 4901284. PMID 27283832.
  2. ^ Cite error: The named reference :0 was invoked but never defined (see the help page).
  3. ^ deMenocal, Peter B. (2001). "Cultural Responses to Climate Change During the Late Holocene". Science. 292 (5517): 667–673. Bibcode:2001Sci...292..667D. doi:10.1126/science.1059827. PMID 11303088. S2CID 18642937.
  4. ^ Gibbons, Ann (1993). "How the Akkadian Empire Was Hung Out to Dry". Science. 261 (5124): 985. Bibcode:1993Sci...261..985G. doi:10.1126/science.261.5124.985. PMID 17739611.
  5. ^ Li, Chun-Hai; Li, Yong-Xiang; Zheng, Yun-Fei; Yu, Shi-Yong; Tang, Ling-Yu; Li, Bei-Bei; Cui, Qiao-Yu (August 2018). "A high-resolution pollen record from East China reveals large climate variability near the Northgrippian-Meghalayan boundary (around 4200 years ago) exerted societal influence". Palaeogeography, Palaeoclimatology, Palaeoecology. 512: 156–165. Bibcode:2018PPP...512..156L. doi:10.1016/j.palaeo.2018.07.031. ISSN 0031-0182. S2CID 133896325.
  6. ^ Cite error: The named reference Staubwasser2003 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Kochhar2017 was invoked but never defined (see the help page).
  8. ^ Voosen, Paul (August 8, 2018). "Massive drought or myth? Scientists spar over an ancient climate event behind our new geological age". Science. Retrieved 9 January 2020.