4.2 kiloyear event

The 4.2 kiloyear BP aridification event was one of the most severe climatic events of the Holocene period in terms of impact on cultural upheaval. Starting in ≈2200 BC, it probably lasted the entire 22nd century BC. It is very likely that it caused the collapse of the Old Kingdom in Egypt as well as the Akkadian Empire in Mesopotamia. [cite journal | author = Gibbons, Ann | year = 1993 | title = How the Akkadian Empire Was Hung Out to Dry | journal = Science | volume = 261 | issue = 5124 | pages = 985 | doi = 10.1126/science.261.5124.985 ] Also, the drought may have initiated southeastward habitat tracking within the Harappan cultural domain.cite journal |last=Staubwasser |first=M. |authorlink= |coauthors="et al." |year=2003 |month= |title=Climate change at the 4.2 ka BP termination of the Indus valley civilization and Holocene south Asian monsoon variability |journal=Geophysical Research Letters |volume=30 |issue=8 |pages=1425 |doi=10.1029/2002GL016822 |url= |accessdate= |quote= ]

Evidence

A phase of intense aridity in ≈4.2 ka BP is well recorded across North Africa, [ cite journal | last = Gasse | first = Françoise | authorlink = | coauthors = Van Campo, Elise | year = 1994 | month = | title = Abrupt post-glacial climate events in West Asia and North Africa monsoon domains | journal = Earth and Planetary Science Letters | volume = 126 | issue = 4 | pages = 435–456 | doi = 10.1016/0012-821X(94)90123-6 | url = | accessdate = | quote = ] the Middle East, [ cite journal | last = Bar-Matthews | first = Miryam | authorlink = | coauthors = Ayalon, Avner; Kaufman, Aaron | year = 1997 | month = | title = Late Quaternary Paleoclimate in the Eastern Mediterranean Region from Stable Isotope Analysis of Speleothems at Soreq Cave, Israel | journal = Quaternary Research | volume = 47 | issue = 2 | pages = 155–168 | doi = 10.1006/qres.1997.1883 | url = | accessdate = | quote = ] the Red Sea, [cite journal |last=Arz |first=Helge W. |authorlink= |coauthors="et al." |year=2006 |month= |title=A pronounced dry event recorded around 4.2 ka in brine sediments from the northern Red Sea |journal=Quaternary Research |volume=66 |issue=3 |pages=432-441 |doi=10.1016/j.yqres.2006.05.006 |url= |accessdate= |quote= ] the Arabian peninsula, cite journal | last = Parker | first = Adrian G. | authorlink = | coauthors = "et al." | year = 2006 | month = | title = A record of Holocene climate change from lake geochemical analyses in southeastern Arabia | journal = Quaternary Research | volume = 66 | issue = 3 | pages = 465–476 | doi = 10.1016/j.yqres.2006.07.001 | url = http://www.gulfnexus.org/articles/geo/2006a%20Parker%20et%20al.pdf | accessdate = | quote = ] the Indian subcontinent, and even midcontinental North America. [cite journal | author = Booth, Robert K.; "et al." | year = 2005 | title = A severe centennial-scale drought in midcontinental North America 4200 years ago and apparent global linkages | journal = The Holocene | volume = 15 | issue = 3 | pages = 321-328 | doi = 10.1191/0959683605hl825ft ] Evidence has also been found in an Italian cave flowstone,cite journal | author = Drysdale, Russell; "et al." | year = 2005 | title = Late Holocene drought responsible for the collapse of Old World civilizations is recorded in an Italian cave flowstone | journal = Geology | volume = 34 | issue = 2 | pages = 101-104 | doi = 10.1130/G22103.1 ] and in Andean glacier ice.cite journal | author = Davis, Mary E.; Thompson, Lonnie G. | year = 2006 | title = An Andean ice-core record of a Middle Holocene mega-drought in North Africa and Asia | journal = Annals of Glaciology | volume = 43 | issue = | pages = 34-41 | url = http://www-bprc.mps.ohio-state.edu/Icecore/Abstracts/Annals%202006%20Davis%20&%20LGT.pdf ]

The 22nd century BC drought also correlates with a cooling event in the North Atlantic, known as "Bond event 3".cite journal| author = Bond, G. | coauthors = "et al." | url=http://rivernet.ncsu.edu/courselocker/PaleoClimate/Bond%20et%20al.,%201997%20Millenial%20Scale%20Holocene%20Change.pdf | year = 1997 | title = A Pervasive Millennial-Scale Cycle in North Atlantic Holocene and Glacial Climates | journal = Science | volume = 278 | issue = 5341 | pages = 1257-1266 | doi = 10.1126/science.278.5341.1257 ]

Aftermath

Ancient Egypt

In ca. 2150 BC the Old Kingdom was hit by a series of exceptionally low Nile floods, which was instrumental in the sudden collapse of centralized government in ancient Egypt. [cite journal | author = Stanley, Jean-Daniel; "et al." | year = 2003 | title = Nile flow failure at the end of the Old Kingdom, Egypt: Strontium isotopic and petrologic evidence | journal = Geoarchaeology | volume = 18 | issue = 3 | pages = 395-402 | doi = 10.1002/gea.10065 ] Famines, social disorder, and fragmentation during a period of approximately 40 years were followed by a phase of rehabilitation and restoration of order in various provinces. Egypt was eventually reunified within a new paradigm of kingship. The process of recovery depended on capable provincial administrators, the deployment of the idea of justice, irrigation projects, and an administrative reform.

Mesopotamia

The aridification of Mesopotamia may have been related to the onset of cooler sea surface temperatures in the North Atlantic (Bond event 3), as analysis of the modern instrumental record shows that large (50%) interannual reductions in Mesopotamian water supply result when subpolar northwest Atlantic sea surface temperatures are anomalously cool. cite journal | last = Cullen | first = Heidi M. | authorlink = | coauthors = deMenocal, Peter B. | year = 2000 | month = | title = North Atlantic influence on Tigris-Euphrates streamflow | journal = International Journal of Climatology | volume = 20 | issue = 8 | pages = 853&ndash;863 | doi = 10.1002/1097-0088(20000630)20:8<853::AID-JOC497>3.0.CO;2-M | url = | accessdate = | quote = ] The headwaters of the Tigris and Euphrates Rivers are fed by elevation-induced capture of winter Mediterranean rainfall.

The Akkadian Empire — which in 2300 B.C. was the first to subsume independent societies into a single state — was brought low by a wide-ranging, centuries-long drought. [cite journal | author = Kerr, Richard A. | year = 1998 | title = Sea-Floor Dust Shows Drought Felled Akkadian Empire | journal = Science | volume = 279 | issue = 5349 | pages = 325-326 | doi = 10.1126/science.279.5349.325 ] Archaeological evidence documents widespread abandonment of the agricultural plains of northern Mesopotamia and dramatic influxes of refugees into southern Mesopotamia around 2170 BC. cite journal | last = Weiss | first = H. | authorlink = | coauthors = "et al." | year = 1993 | month = | title = The Genesis and Collapse of Third Millennium North Mesopotamian Civilization | journal = Science | volume = 261 | issue = 5124 | pages = 995&ndash;1004 | doi = 10.1126/science.261.5124.995 | url = | accessdate = | quote = ] A 180-km-long wall, the “Repeller of the Amorites,” was built across central Mesopotamia to stem nomadic incursions to the south. Around 2150 BC, the Guti, which originally inhabited the Zagros Mountains, defeated the demoralized Akkadian army, took Akkad, and destroyed it around 2115 BC.

Resettlement of the northern plains by smaller, sedentary populations occurred near 1900 BC, three centuries after the collapse.

Arabian peninsula

In the Persian Gulf region, there is a sudden change in settlement pattern, style of pottery and tombs at this time. The 22nd century BC drought marks the end of the Umm al-Nar period and the change to the Wadi Suq period.

China

The drought may have caused the collapse of Neolithic Cultures around Central China during the late third millennium BC. [ cite journal | author = Wu Wenxiang; Liu Tungsheng | year = 2004 | month = | title = Possible role of the “Holocene Event 3” on the collapse of Neolithic Cultures around the Central Plain of China | journal = Quaternary International | volume = 117 | issue = 1 | pages = 153&ndash;166 | doi = 10.1016/S1040-6182(03)00125-3 | url = | accessdate = | quote = ]

Further reading

*Ristvet, L. (2003). "Agriculture, Settlement, and Abrupt Climate Change: The 4.2ka BP event in Northern Mesopotamia". In: "American Geophysical Union", Fall Meeting 2003, abstract #PP22C-02.

External links

* [http://www.friesian.com/notes/oldking.htm The Egyptian Old Kingdom, Sumer and Akkad]
* [http://nefertiti.iwebland.com/the_end_of_the_old_kingdom.htm The End of the Old Kingdom]

References