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Detail of a man depicted on an Uruk vase, Pergamon Museum. The Uruk civilization arose as it expertly adapted to the new climate.

Rising to the Challenge: Innovative Civilizations Advanced Through Climate Change

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Beginning around 90,000 years ago, during an interglacial period, Anatomically Modern Humans were able to take advantage of the favorable climatic conditions and migrate throughout Africa and into Asia. Soon thereafter, identifiable culture can be found in the archaeological record. As far as can be told, it was Homo Sapiens living in Africa that would make the first symbolic paintings, but Neanderthals soon did this as well.

Modern Humans showed a particular ability to adapt, as they continued to thrive throughout the renewed period of glaciations, known as the Wisconsin or Wurm Glaciations, which occurred between 35,000 and 11,500 years ago. Neanderthal populations were either assimilated by the Modern Humans or became extinct during this time.

A reconstructed Neanderthal skeleton, right, is displayed next to a modern human skeleton at the Museum of Natural History in New York.

A reconstructed Neanderthal skeleton, right, is displayed next to a modern human skeleton at the Museum of Natural History in New York. (Museum of Natural History in New York )

At this time of climatic extremes, people expanded their social interactions - as evidenced by complex and mobile artwork, as well as increasingly sophisticated burial customs. These Mesolithic people also began to domesticate a variety of plants and animals, opening the path to the later agricultural revolution.

The Younger Dryas

Around 15,000 years ago, humanity was thriving as the glacial climate became milder. Archaeological evidence shows a population spike at this time as new technologies and warmer weather suddenly increased the amount of available food. However, far removed from most of the world’s population, in North America around 13,000 years ago several glacial lakes would burst forth, sending their fresh cold waters into the saline and warm waters of the Atlantic Ocean. The effects of these glacial lakes flowing into the ocean was apparently much more rapid than previously thought. Over the period of a few months the climate began to change.

It was possibly around 12,800 years ago when a glacial cold snap occurred. This is known as the Younger Dryas and it was named after a flower that was common during this time of rapid change. The return to extreme weather, which lasted for around 1,500 years, saw a population crash and a restructuring of the subsistence methods of early cultures. During this epoch, sea levels rose by up to 100 meters (328.08 ft.) likely causing massive displacements of coastal populations and perhaps providing a foundation for the globally ubiquitous occurrence of "Flood Mythology."

Post Glacial Sea level Rise (Image: theancientneareast)

While humanity scraped its way back from the disaster of the climatic changes, the plants and animals they had lived on were no longer as plentiful - and for many the hunter-gatherer way of life was no longer adequate. Relatively quickly a new way of life began to develop alongside new technologies and material culture. This change is shown in the archaeological record by improved stone tools - and thus dawns the New Stone Age or Neolithic Period at about 12,500 years ago. One particular culture that exemplified these changes were the Natufians of the Western Levant. Their presence coincides with the Younger Dryas, suggesting just how specialized they were.

Giant mortars from Natufian Culture.

Giant mortars from Natufian Culture. (Hanay/CC BY SA 3.0)

 Part of this cultural change can also be witnessed in the stone structures that begin to appear at this time. It was around 11,000 years ago that a stone temple was first built on the already sacred site of Göbekli Tepe in Southern Anatolia. At this same time, the first stone buildings were erected at Jericho over 600 kilometers (nearly 400 miles) to the south in the Levant. The work at Göbekli Tepe was most intense during its early phases, suggesting a transitional culture that arose quickly in response to the altered climate and hinting that wondrous things may have been lost beneath the rising seas.

Göbekli Tepe. The whole area was filled with stones and dirt.

Göbekli Tepe. The whole area was filled with stones and dirt. (CC BY SA 3.0 )

From 7,500 to 5,700 BC Jericho and another settlement, Çatalhöyük in Anatolia (400 miles west of Göbekli Tepe), enjoyed periods of large and stable populations. But they fall something short of specialized societies with communal institutions that we look to as the first cities. Also during this time, 7,500-7,000 BC, the Neolithic Subluvial climate phase begins in northern Africa and lasts until about 5,000 BC. During this epoch, the Sahara Desert was substantially wetter than today, comparable to a savannah. As the Neolithic Subluvial ended the desertification of the Sahara began. Many people, and animals, inhabiting the north African savannah made their way to the Nile Valley, which became one of the few places in northeast Africa where concentrated populations could find a dependable supply of fresh water.

Acacia tree in Kenya savannah.

Acacia tree in Kenya savannah. (Kev Moses/CC BY 2.0)

The Holocene

When the chill of the Younger Dryas was over, just over 10,000 years ago, the modern geologic era, known as the Holocene interglacial period, began. The Holocene brought with it markedly warmer temperatures. Soon agriculture emerged around the world in almost all major population groups. Particularly successful during the early Holocene were the Halaf people of the Levant, who built community focused villages which were the forerunners to the walled cities of future millennia.

The warming temperatures at this time also caused additional rises in sea level and a shift in rainfall patterns. The failing reliability of seasonal rain in some regions likely led to some of the shifting population patterns that can be witnessed in the archaeological record of the Near East. Long term population shifts eventually led to relatively dense populations in the lands along major rivers.

A Neolithic grinding stone for grain

A Neolithic grinding stone for grain. (José-Manuel Benito Álvarez/ CC BY SA 2.5 )

Even as the climate was warming its way out of the Younger Dryas, an event of uncertain origin but certain impact occurred. Known as the 8.2 Kiloyear Event, this sudden and brief burst of cold weather coincides with the end of the cultures of Jericho, Çatalhöyük and any remnants of Göbekli Tepe culture. They are replaced primarily by the Halaf, the canal building Hassuna-Samarra and the Ubaid cultures in Mesopotamia - all of whom adopted agrarian focused subsistence methods. These different cultures are primarily distinguished in the archaeological record by the style of pottery they developed. Pottery was a hallmark of the new agricultural way of life which necessitated a storage capacity for food surplus.

By 8,000 years ago, the Earth’s climate had become increasingly warm and moist, creating a period known as the Holocene Climatic Optimum. This was the warmest period in the past 125,000 years, with minimal glaciations and the highest sea levels. During this time, Britain was slowly cut off from mainland Europe by the rising sea levels, and by 6,500 BC the land bridge to continental Europe known as Doggerland was submerged.

The Mesolithic people of Doggerland.

The Mesolithic people of Doggerland. (Alexander Maleev)

For the first two thousand years of the Holocene, sea levels continued to rise sharply as massive glaciers melted away. It was possibly sometime during this era when the Black Sea was flooded by an overflow from the Mediterranean Sea through the straits of the Bosporus. While the timing and rapidity of this flooding is under debate, it is clear that significant areas of inhabited land, was, as in the case of Doggerland, lost to the sea. These rising oceans eventually reached one meter (3.28 ft.) above modern levels.

Holocene Sea level (Image: theancientneareast)

The warmest period of the Holocene coincides with the Neolithic Agricultural Revolution. It was at this point, around 6,000 BC that most cultures begin what was likely an imperative switch from a hunter-gatherer existence, to one based on agriculture and domestication of animals.

It was during this Climate Optimum that the archaeological record in West Asia shows the first evidence of clay tokens used to represent trading goods by the Ubaid Culture in Mesopotamia. Also at this time, the Peiligang culture in East Asia began to develop its own advanced trade and farming practices.

Ubaid Stamp seal and modern impression: horned animal and bird.

Ubaid Stamp seal and modern impression: horned animal and bird. (The Met)

Although these cultures where very successful for a time, the climate upon which they relied for their agricultural methods gradually changed. The warm and moist weather shifted out of the Climatic Optimum into the milder modern climate, which again caused a change in rainfall patterns along with a slow lowering of the sea level by a couple of meters.

The Rise of Civilization

By 5,400 BC a new culture expertly adapted to the new climate and was based on irrigated agriculture along the southern courses of the Tigris and Euphrates Rivers. We know these peoples as the Uruk Culture, after one of the regions primary archaeological sites. It is at this time that towns such as Eridu and Uruk, which would soon grow into fully fledged cities, begin to develop.

The Uruk archaeological site in Mesopotamia.

The Uruk archaeological site in Mesopotamia. (SAC Andy Holmes/OGL)

Around 3,700 BC the climate became milder with the emergence of the modern Subatlantic Climatic Period. Within 500 years of our modern climate, the Uruk Culture had become dominant in Mesopotamia and we can see the development of writing and all the trappings of what we deem civilization.

Uruk Culture is known for its part in the worldwide revolution in agriculture from that period due to its reliance on the use of irrigation technology. This can be witnessed also in East Asia along the Yellow River, where the Yangshao people thrived, in Africa, along the Nile Valley, where Egyptian culture was taking root, and also along the Indus Valley with its own unique and enigmatic culture.

Ancient Egyptian sculptors making a statue.

Ancient Egyptian sculptors making a statue. (Underground Science )

With the use of irrigation, people had become less dependent on good weather and had a much greater control over their food supplies. This stable production capacity led to a population boom and the growth of cities, which in turn led to the expanded use of metal crafting technology, giving rise to the Bronze Age, and finally onto the modern era.

Throughout the modern Subatlantic Climate the substantial foundations of our culture have remained the same. Irrigated agriculture and livestock provide most of the world’s food supply. Whether these methods can sustain a global population given another climatic shift would be speculative, but it is clear that climate change cannot only totally alter a culture’s subsistence pattern - but it may be the only thing which has ever done so.

Top Image: Detail of a m an depicted on an Uruk vase, Pergamon Museum. The Uruk civilization arose as it expertly adapted to the new climate. Source: CC BY 3.0

By Robert McRoberts


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Rob Mcroberts's picture

Robert F McRoberts

Robert McRoberts is  a graduate of UCLA with degrees in Ancient History and Near Eastern Languages and Cultures.  He has a lifelong interest in History and Mythology and has published a number of articles with a focus on the ancient... Read More

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