4.2 kiloyear event
Encyclopedia
The 4.2 kiloyear BP
arid
ification 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 to have caused the collapse of the Old Kingdom
in Egypt
as well as the Akkadian Empire in Mesopotamia
. The drought may have also initiated southeastward habitat tracking within the Harappan cultural domain
.
is well recorded across North Africa
, the Middle East
, the Red Sea
, the Arabian peninsula
, the Indian subcontinent
, and even midcontinental North America
. Glacier
s throughout the mountain ranges of western Canada
advanced at about this time. Evidence has also been found in an Italian cave flowstone, and in Andean glacier ice.
The onset of the aridification in Mesopotamia near 4100 B.P also coincided with a cooling event in the North Atlantic, known as Bond event
3.
was hit by a series of exceptionally low Nile
floods, which was instrumental in the sudden collapse of centralized government in ancient Egypt. 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.
and Euphrates
Rivers are fed by elevation-induced capture of winter Mediterranean rainfall.
The Akkadian Empire—which in 2300 B.C. was the second civilization to subsume independent societies into a single state (the first being ancient Egypt
at around 3100 BC) —was brought low by a wide-ranging, centuries-long drought. Archaeological evidence documents widespread abandonment of the agricultural plains of northern Mesopotamia and dramatic influxes of refugees into southern Mesopotamia around 2170 BC. A 180-km-long wall, the "Repeller of the Amorite
s," was built across central Mesopotamia to stem nomadic incursions to the south. Around 2150 BC, the Guti
, who originally inhabited the Zagros Mountains
, defeated the demoralized Akkadian army, took Akkad
, and destroyed it around 2115 BC. Widespread agricultural change in the Near East is visible at the end of the third millennium BC.
Resettlement of the northern plains by smaller, sedentary populations occurred near 1900 BC, three centuries after the collapse.
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.
was hit by a cooling that made the paddies shortfall in output or even no seeds were gathered. The scarcity in natural resource led to substantial decrease in population and subsequent drop in archaeological sites. About 4000 cal. yr BP Longshan culture was displaced by Yueshi culture which was relatively underdeveloped, simple and unsophisticated.
Before Present
Before Present years is a time scale used in archaeology, geology, and other scientific disciplines to specify when events in the past occurred. Because the "present" time changes, standard practice is to use AD 1950 as the origin of the age scale, reflecting the fact that radiocarbon...
arid
Arid
A region is said to be arid when it is characterized by a severe lack of available water, to the extent of hindering or even preventing the growth and development of plant and animal life...
ification event was one of the most severe climatic events of 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"...
period in terms of impact on cultural upheaval. Starting in ≈2200 BC, it probably lasted the entire 22nd century BC
22nd century BC
The 22nd century BC is a century which lasted from the year 2200 BC to 2101 BC.-Events:right|thumb|170px|The [[deluge |Deluge]] tablet of the [[Gilgamesh epic]] in [[Akkadian language|Akkadian]]...
. It is very likely to have caused the collapse of the Old Kingdom
Old Kingdom
Old Kingdom is the name given to the period in the 3rd millennium BC when Egypt attained its first continuous peak of civilization in complexity and achievement – the first of three so-called "Kingdom" periods, which mark the high points of civilization in the lower Nile Valley .The term itself was...
in Egypt
Egypt
Egypt , officially the Arab Republic of Egypt, Arabic: , is a country mainly in North Africa, with the Sinai Peninsula forming a land bridge in Southwest Asia. Egypt is thus a transcontinental country, and a major power in Africa, the Mediterranean Basin, the Middle East and the Muslim world...
as well as the Akkadian Empire in Mesopotamia
Mesopotamia
Mesopotamia is a toponym for the area of the Tigris–Euphrates river system, largely corresponding to modern-day Iraq, northeastern Syria, southeastern Turkey and southwestern Iran.Widely considered to be the cradle of civilization, Bronze Age Mesopotamia included Sumer and the...
. The drought may have also initiated southeastward habitat tracking within the Harappan cultural domain
Indus Valley Civilization
The Indus Valley Civilization was a Bronze Age civilization that was located in the northwestern region of the Indian subcontinent, consisting of what is now mainly modern-day Pakistan and northwest India...
.
Evidence
A phase of intense aridity in ≈4.2 ka BPBefore Present
Before Present years is a time scale used in archaeology, geology, and other scientific disciplines to specify when events in the past occurred. Because the "present" time changes, standard practice is to use AD 1950 as the origin of the age scale, reflecting the fact that radiocarbon...
is well recorded across 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...
, 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 Red Sea
Red Sea
The Red Sea is a seawater inlet of the Indian Ocean, lying between Africa and Asia. The connection to the ocean is in the south through the Bab el Mandeb strait and the Gulf of Aden. In the north, there is the Sinai Peninsula, the Gulf of Aqaba, and the Gulf of Suez...
, the Arabian peninsula
Arabian Peninsula
The Arabian Peninsula is a land mass situated north-east of Africa. Also known as Arabia or the Arabian subcontinent, it is the world's largest peninsula and covers 3,237,500 km2...
, the Indian subcontinent
Indian subcontinent
The Indian subcontinent, also Indian Subcontinent, Indo-Pak Subcontinent or South Asian Subcontinent is a region of the Asian continent on the Indian tectonic plate from the Hindu Kush or Hindu Koh, Himalayas and including the Kuen Lun and Karakoram ranges, forming a land mass which extends...
, and even midcontinental North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
. Glacier
Glacier
A glacier is a large persistent body of ice that forms where the accumulation of snow exceeds its ablation over many years, often centuries. At least 0.1 km² in area and 50 m thick, but often much larger, a glacier slowly deforms and flows due to stresses induced by its weight...
s throughout the mountain ranges of western Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
advanced at about this time. Evidence has also been found in an Italian cave flowstone, and in Andean glacier ice.
The onset of the aridification in Mesopotamia near 4100 B.P also coincided with a cooling event in the North Atlantic, known as 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...
3.
Ancient Egypt
In ca. 2150 BC the Old KingdomOld Kingdom
Old Kingdom is the name given to the period in the 3rd millennium BC when Egypt attained its first continuous peak of civilization in complexity and achievement – the first of three so-called "Kingdom" periods, which mark the high points of civilization in the lower Nile Valley .The term itself was...
was hit by a series of exceptionally low Nile
Nile
The Nile is a major north-flowing river in North Africa, generally regarded as the longest river in the world. It is long. It runs through the ten countries of Sudan, South Sudan, Burundi, Rwanda, Democratic Republic of the Congo, Tanzania, Kenya, Ethiopia, Uganda and Egypt.The Nile has two major...
floods, which was instrumental in the sudden collapse of centralized government in ancient Egypt. 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. The headwaters of the TigrisTigris
The Tigris River is the eastern member of the two great rivers that define Mesopotamia, the other being the Euphrates. The river flows south from the mountains of southeastern Turkey through Iraq.-Geography:...
and Euphrates
Euphrates
The Euphrates is the longest and one of the most historically important rivers of Western Asia. Together with the Tigris, it is one of the two defining rivers of Mesopotamia...
Rivers are fed by elevation-induced capture of winter Mediterranean rainfall.
The Akkadian Empire—which in 2300 B.C. was the second civilization to subsume independent societies into a single state (the first being ancient Egypt
Ancient Egypt
Ancient Egypt was an ancient civilization of Northeastern Africa, concentrated along the lower reaches of the Nile River in what is now the modern country of Egypt. Egyptian civilization coalesced around 3150 BC with the political unification of Upper and Lower Egypt under the first pharaoh...
at around 3100 BC) —was brought low by a wide-ranging, centuries-long drought. Archaeological evidence documents widespread abandonment of the agricultural plains of northern Mesopotamia and dramatic influxes of refugees into southern Mesopotamia around 2170 BC. A 180-km-long wall, the "Repeller of the Amorite
Amorite
Amorite refers to an ancient Semitic people who occupied large parts of Mesopotamia from the 21st Century BC...
s," was built across central Mesopotamia to stem nomadic incursions to the south. Around 2150 BC, the Guti
Gutium
The Gutians were a tribe that overran southern Mesopotamia when the Akkadian empire collapsed in approximately 2154 BC....
, who originally inhabited the Zagros Mountains
Zagros Mountains
The Zagros Mountains are the largest mountain range in Iran and Iraq. With a total length of 1,500 km , from northwestern Iran, and roughly correlating with Iran's western border, the Zagros range spans the whole length of the western and southwestern Iranian plateau and ends at the Strait of...
, defeated the demoralized Akkadian army, took Akkad
Akkad
The Akkadian Empire was an empire centered in the city of Akkad and its surrounding region in Mesopotamia....
, and destroyed it around 2115 BC. Widespread agricultural change in the Near East is visible at the end of the third millennium BC.
Resettlement of the northern plains by smaller, sedentary populations occurred near 1900 BC, three centuries after the collapse.
Arabian peninsula
In the Persian GulfPersian Gulf
The Persian Gulf, in Southwest Asia, is an extension of the Indian Ocean located between Iran and the Arabian Peninsula.The Persian Gulf was the focus of the 1980–1988 Iran-Iraq War, in which each side attacked the other's oil tankers...
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. In the Yishu River Basin, the flourishing Longshan cultureLongshan culture
The Longshan culture was a late Neolithic culture in China, centered on the central and lower Yellow River and dated from about 3000 BC to 2000 BC...
was hit by a cooling that made the paddies shortfall in output or even no seeds were gathered. The scarcity in natural resource led to substantial decrease in population and subsequent drop in archaeological sites. About 4000 cal. yr BP Longshan culture was displaced by Yueshi culture which was relatively underdeveloped, simple and unsophisticated.
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.