5.9 kiloyear event
Encyclopedia
The 5.9 kiloyear event was one of the most intense aridification
Aridification
Aridification is the process of a region becoming increasingly dry. It refers to long term change rather than seasonal variation.It is often measured as the reduction of average soil moisture content....

 events during the Holocene
Holocene
The Holocene is a geological epoch which began at the end of the Pleistocene and continues to the present. The Holocene is part of the Quaternary period. Its name comes from the Greek words and , meaning "entirely recent"...

. It occurred around 3900 BC, ending the Neolithic Subpluvial
Neolithic Subpluvial
The Neolithic Subpluvial — sometimes called the Holocene Wet Phase — was an extended period of wet and rainy conditions in the climate history of northern Africa...

 and probably initiated the most recent desiccation
Desiccation
Desiccation is the state of extreme dryness, or the process of extreme drying. A desiccant is a hygroscopic substance that induces or sustains such a state in its local vicinity in a moderately sealed container.-Science:...

 of the Sahara
Sahara
The Sahara is the world's second largest desert, after Antarctica. At over , it covers most of Northern Africa, making it almost as large as Europe or the United States. The Sahara stretches from the Red Sea, including parts of the Mediterranean coasts, to the outskirts of the Atlantic Ocean...

 desert. Thus, it also triggered worldwide migration to river valleys, e.g. from central North Africa
North Africa
North Africa or Northern Africa is the northernmost region of the African continent, linked by the Sahara to Sub-Saharan Africa. Geopolitically, the United Nations definition of Northern Africa includes eight countries or territories; Algeria, Egypt, Libya, Morocco, South Sudan, Sudan, Tunisia, and...

 to the Nile valley, which eventually led to the emergence of the first complex, highly organised, state-level societies in the 4th millennium BC
4th millennium BC
The 4th millennium BC saw major changes in human culture. It marked the beginning of the Bronze Age and of writing.The city states of Sumer and the kingdom of Egypt were established and grew to prominence. Agriculture spread widely across Eurasia...

. It is associated with the last round of the Sahara pump theory
Sahara pump theory
The Sahara pump theory is a hypothesis that explains how flora and fauna migrated between Eurasia and Africa via a Levantine land bridge. The theory observes that extended periods of abundant rainfall lasting many thousands of years in Africa are associated with a "wet Sahara" phase, during which...

.

A model by Claussen et al. (1999) suggested rapid desertification associated with vegetation atmosphere interactions following a cooling event, Bond event
Bond event
Bond events are North Atlantic climate fluctuations occurring every ≈1,470 ± 500 years throughout the Holocene. Eight such events have been identified, primarily from fluctuations in ice-rafted debris. Bond events may be the interglacial relatives of the glacial Dansgaard–Oeschger events, with a...

 4. Bond et al. (1997) identified a North Atlantic cooling episode 5,900 years ago from ice-rafted debris, as well as other such now called Bond events that indicate the existence of a quasiperiodic cycle of Atlantic cooling events, which occur approximately every 1470 years ± 500 years. For some reason, all of the earlier of these arid events (including the 8.2 kiloyear event
8.2 kiloyear event
The 8.2 kiloyear event is the term that climatologists have adopted for a sudden decrease in global temperatures that occurred approximately 8,200 years before the present, or c. 6,200 BCE, and which lasted for the next two to four centuries...

) were followed by recovery, as attested by the wealth of evidence of humid conditions in the Sahara between 10,000 and 6,000 BP. However, it appears that the 5.9 kiloyear event was followed by a partial recovery at best, with accelerated desiccation in the millennium that followed. For example, Cremaschi (1998) describes evidence of rapid aridification
Aridification
Aridification is the process of a region becoming increasingly dry. It refers to long term change rather than seasonal variation.It is often measured as the reduction of average soil moisture content....

 in Tadrart Acacus
Tadrart Acacus
The Acacus Mountains or Tadrart Acacus form a mountain range in the desert of the of the Ghat District in western Libya, part of the Sahara. They are situated east of the Libyan city of Ghat and stretch north from the Algerian border about 100 km. Tadrart means 'mountain' in the native...

 of southwestern Libya
Libya
Libya is an African country in the Maghreb region of North Africa bordered by the Mediterranean Sea to the north, Egypt to the east, Sudan to the southeast, Chad and Niger to the south, and Algeria and Tunisia to the west....

, in the form of increased aeolian erosion, sand incursions and the collapse of the roofs of rock shelters.

In the Middle East
Middle East
The Middle East is a region that encompasses Western Asia and Northern Africa. It is often used as a synonym for Near East, in opposition to Far East...

 the 5.9 kiloyear event led to the abrupt end of the Ubaid period
Ubaid period
The Ubaid period is a prehistoric period of Mesopotamia. The tell of al-`Ubaid west of nearby Ur in southern Iraq's Dhi Qar Governorate has given its name to the prehistoric Pottery Neolithic to Chalcolithic culture, which represents the earliest settlement on the alluvial plain of southern...

.

The 5.9 kiloyear event was also recorded as a cold event in the Erhai Lake
Erhai Lake
Er Lake, Chinese Erhai , is an alpine fault lake in Yunnan province, China. Its name means "Ear-shaped Sea", due to its shape as seen by locals and travellers. Er Lake was also known as Yeyuze or Kunming Lake in ancient times. A commonly-seen mistranslation is Erhai Lake.-Geography:Erhai is...

 (China) sediments.

Historically the period of the 5.9 kiloyear event is associated with the increased violence noticed in both Egypt and throughout the Middle East, leading eventually to the Early Dynastic Period
Early Dynastic Period of Egypt
The Archaic or Early Dynastic Period of Egypt immediately follows the unification of Lower and Upper Egypt c. 3100 BC. It is generally taken to include the First and Second Dynasties, lasting from the Protodynastic Period of Egypt until about 2686 BC, or the beginning of the Old Kingdom...

 in both the First Dynasty of Egypt
First dynasty of Egypt
The first dynasty of Ancient Egypt is often combined with the Dynasty II under the group title, Early Dynastic Period of Egypt...

 and Sumer
Sumer
Sumer was a civilization and historical region in southern Mesopotamia, modern Iraq during the Chalcolithic and Early Bronze Age....

. James DeMeo and Steve Taylor suggest that this period is associated with the rise of patriarchy
Patriarchy
Patriarchy is a social system in which the role of the male as the primary authority figure is central to social organization, and where fathers hold authority over women, children, and property. It implies the institutions of male rule and privilege, and entails female subordination...

, institutionalised warfare
War
War is a state of organized, armed, and often prolonged conflict carried on between states, nations, or other parties typified by extreme aggression, social disruption, and usually high mortality. War should be understood as an actual, intentional and widespread armed conflict between political...

, social stratification
Social stratification
In sociology the social stratification is a concept of class, involving the "classification of persons into groups based on shared socio-economic conditions ... a relational set of inequalities with economic, social, political and ideological dimensions."...

, abuse of children
Child abuse
Child abuse is the physical, sexual, emotional mistreatment, or neglect of a child. In the United States, the Centers for Disease Control and Prevention and the Department of Children And Families define child maltreatment as any act or series of acts of commission or omission by a parent or...

, the development of the human ego, separation from the body, the rise of anthropomorphic gods and the concept of linear historic time.
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