The entire story of human social evolution, which has led to modern civilization, has been shaped by the climatic changes of the current Ice Age.
For the last 2.6 million years, the planet earth has been locked in an Ice Age known in geologic time as the Quaternary Period. All of human existence has occurred during this time frame, which has been marked by repeated glaciations of the planet. These cycles of glaciations have occurred at regular intervals throughout our planets history. Massive ice sheets have often extended to cover much of the worlds land mass, then have retreated for tens of thousands of years.
Early Human Culture
Beginning around 90,000 years ago, during an interglacial period, Anatomically Modern Humans where able to take advantage of the favorable climatic conditions and migrate throughout Africa and into Asia. It was Homo Sapiens living in Africa that would first make symbolic paintings but Neanderthals soon did this as well.i Neanderthals living in Europe and the Ancient Near East from 100,000 – 20,000 BCE were also involved in Middle Stone Age/Mesolithic Religion with its focus on animal totems, such as the cave bear cult and a chthonic death cult which involved ritual cave burials.ii
Modern Humans showed an 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 during this time were either assimilated by the Modern Humans or became extinct.
During this time of climatic extremes, people expanded their social interactions as evidenced by complex and mobile artwork,iii as well as increasingly sophisticated burial customs.iv These Mesolithic people also began to domesticate a variety of plants and animals,v 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. Archeological 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 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.vi
It was possibly around 12,800 years ago that this glacial cold snap occurred, known as the Younger Dryas, after a flower that was common during this time. This 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 100m likely causing massive displacements of coastal populations.
When humanity scrapes its way back from the disaster of the climatic changes the plants and animals they had lived on are no longer as plentiful or in the same locales. Relatively quickly a new way of life began to develop together with new technologies and material culture. This change is evidenced in the archeological record of 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 distinctiveness in the archeological record coincides with the Younger Dryas suggesting how specialized they were.
Part of this 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. The work at Göbekli Tepe was most intense during its early phases suggesting a transitional culture that arose quickly in response to the climatic changes.
From 7,500 to 5,700 BCE Jericho and Çatalhöyük in Anatolia enjoyed periods of large and stable populations but they fall something short of the specialized societies with communal institutions that we look to as the first cities.
Also during this time, 7,500-7,000 BCE, the Neolithic Subpluvial begins in northern Africa and lasts until about 5,000 BCE. During this epoch the Sahara desert was substantially wetter than today, comparable to a savannah. As the Neolithic Subluvial ended 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 for a dependable supply of fresh water.
When the chill of the Younger Dyras was over, 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 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 which eventually led to the relatively dense populations of the lands along major rivers.vii
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 now replaced primarily by the Halaf, the canal building Hassuna-Samarra and the Ubaid cultures in Mesopotamia who adopted more agrarian subsistence methods.
These different cultures are primarily distinguished in the archeological 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 became increasingly warmer and moister, creating a period known as the Holocene Climatic Optimum. This was the warmest period in the past 125,000 years, with minimal glaciation and the highest sea levels. During this time, Britain was cut off from mainland Europe by the rising sea levels and by 6,500 BCE Doggerland was submerged.viii
For the first two thousand years of the Holocene sea levels continued to rise sharply. Somewhere during this era (or perhaps earlier or later) the Black Sea was flooded by an overflow from the Mediterranean Sea. 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 Doggeland, lost to the sea. These rising oceans eventually reached one meter above modern levels.
The beginning of the Holocene coincides with the Neolithic/Agricultural Revolution, when around 6,000 BCE most humans begin a likely imperative switch from a hunter-gatherer existence, to one based on agriculture and domestication of animals.
It was during the 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.ix Also at this time the Peiligang culture in East Asia began to develop its own advanced trade and farming practices.x
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 BCE a new culture based on irrigated agriculture developed along the southern courses of the Tigris and Euphrates Rivers; known as the Uruk culture after one of its primary sites. It is at this time that the towns such as Eridu and Uruk, which will become fully fledged cities, begin to develop.xi
Around 3,700 BCE the climate became more mild with the emergence of the modern Subatlantic Climatic Period. Within 500 years of our modern climate Uruk culture had become dominant in Mesopotamia and we can see the development of writing and all the trappings of civilization.
Uruk culture is known for its part of the worldwide revolution in agriculture that occurred during this period with its reliance of 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.
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 can not only totally change a culture’s subsistence pattern but it may be the only thing which can do so.
Peter, M, G. Ackermans, G. Schwartz, The Archeology of Syria, Cambridge Press, Cambridge, 2006
Roaf, Michael, Cultural Atlas of Mesopotamia and the Near East, Andromeda Books, Oxford, 2004.
Roux, Georges, Ancient Iraq, Penguin Books, London, 1992
i “An Early Case of Ochre Symbolism: Ochre use by Modern Humans in Qafzeh Cave.” Hovers et al. Current Anthropology, Vol. 44, No. 4, August/October 2003 pp.
491-522.and “Use of Red Ochre by Early Neanderthals”, Klein, Richard, Proceedings of National Academy of Sciences USA, Vol, 109 No. 6. December 20th 2011.
ii Karl J. Narr. “Prehistoric religion“. Britannica online encyclopedia 2008. Retrieved 6-30-2014.
iii Pamela B. Vandiver, Olga Soffer, Bohuslav Klima and Jiři Svoboda, “The Origins of Ceramic Technology at Dolni Věstonice, Czechoslovakia”, Science, New Series, 246, No. 4933 (November 24, 1989:1002-1008).
iv “Oldest Shaman Grave Found: Includes Foot, Animal Parts” Milstein, Mati, National Geographic News, Nov. 4, 2008.
v “Agronomic conditions and crop evolution in Ancient Near Eastern agriculture” Araus, et al, Nature Communications 5, Article 3953, May 23 2014.
vi Big Freeze: Earth Could Plunge into Sudden Ice Age Choi, Charles Q. December 2, 2009).
vii “Past, present and future precipitation in the Middle East: insights from models and observations.” Black et al, Philosophical Transactions of the Royal Society.
viii “Britain’s Atlantis found at bottom of North Sea” Waugh, Rob, Mail Online, July 3rd, 2012
ix “Two Precursors of Writing: Plain and Complex Tokens” Schmandt-Besserat, Denise, The Origins of Writing Barcelona, Dec. 8, 2008
x Liu, Li. The Chinese Neolithic: Trajectories to Early States.
xi Roaf, Michael, Cultural Atlas of Mesopotamia and the Near East, Andromeda Books, Oxford, 2004. pg. 58