Posted on 07/07/2006 4:04:55 PM PDT by blam
Scientists debate role climate change plays in creating civilizations
Tuesday, July 04, 2006
BRADLEY T . LEPPER
One of archaeology’s "big questions" is explaining the origins of civilization. In anthropology, "civilization" has a technical definition.
To qualify as a civilization, a society must have all or most of the following characteristics: cities with large populations; a hierarchical social organization, with a king, pharaoh or president at the top of the organizational chart; an economy based on agriculture; monumental architecture; and a system of record-keeping.
The earliest civilizations arose in Mesopotamia, Egypt, the Indus Valley and northern China. Based on this definition, there were no indigenous civilizations in the Ohio Valley. And the arrival of European civilization derailed any chance of one developing.
Various theories have been proposed to explain how this social complexity developed and why it developed in some areas and not others, but archaeologists and historians have not formulated any one satisfying explanation.
Nick Brooks, a climate-change researcher at the University of East Anglia in England, offers his idea in the latest issue of Quaternary International.
"The emergence of complex societies coincided with or followed a period of increased aridity," which began 8,000 years ago but intensified periodically in subsequent millennia, he said.
In this view, global climate change caused the profound social changes that have been referred to as the "urban revolution."
Brooks states that during large-scale droughts, people would have been forced to concentrate in places where water was available.
The social consequences of this aggregation included the formation of managerial elites who controlled the distribution of resources and directed the construction of large monuments to represent and justify their authority. Brooks sees these worldwide social upheavals as ways societies adapted to changing environments.
Most anthropologists reject such explanations as too simplistic. The environment, they say, cannot alone determine human responses.
But when cultures worldwide adopt similar solutions to similar problems, perhaps it’s useful to view civilization as a successful, if not inevitable, response to global environmental changes.
The editors of this issue of Quaternary International point out that although "no simple rules seem to govern human (cultural) evolution," it is crucial to try to understand how humans respond to environmental catastrophes.
It is increasingly relevant to us today in the wake of devastating tsunamis, hurricanes, earthquakes and the threat of global warming.
Bradley T. Lepper is curator of archaeology at the Ohio Historical Society.
blepper@ohiohistory.org
This was the period of the last 'surge' ice melt that ended the Ice Age and flooded large coastal areas of most continents. Weather patterns and climate shifted dramatically.
Irrigation projects were the first mega-projects; which required high levels of planning, organization, and mobilization of the efforts of large numbers of people. Maybe arid conditions spurred this on.
That entire article is balderdash. EVERYONE knows that the entire planet had a perfect climate in all locations for people to live as one with nature until it was all destroyed by global warming caused by AMERICAN INDUSTRY in the 20th century!
(scarcasm off)
James Burke had a PBS show in which he detailed the relationship between climate and civilization.
http://www.maine.gov/doc/nrimc/mgs/explore/marine/facts/sea-02.htm
Above is a link to the sea level in Maine- when the wild swings stop and the sea level is steady for a thousand years, we get civilization. It would not be possible to have a port city if the ocean level changes a hundred meters in a century.
I like James Burke. He has aa excellent collection of books titled 'Connections.' My son met Burke when he was attending ASU.
As far as dryness is concerned, vast stretches of Eur-Asia and North America were subarctic deserts for most of the last 110,000 years. This was due to the intense dryness which occurs during periods of heavy glaciation.
The Human Genome shows signs of relatively recent (last 50,000 years or so) adaptation to these dry conditions. There are genes that enable the body to shed excess iron (from Ice Age dust). East Asian populations have an eyelid and tearduct form that facilitates keeping dust out of the sinuses.
We live in a relatively wet period compared to the Ice Age.
The other problem you face after a period of rising seas is the almost total loss of the estuaries. Once ocean levels stabilize, the estuaries reform.
From professor Stepehen Oppenheimer's excellent book, Eden In The East, Chapter one, titled, "An Ice And Three Floods," page 25, "the three floods were respectively , around 14,000, 11,500 and 8,000 years ago (See figure 1)
It was the last flood 8,000 years ago that opened up the Straits Of Mallacca(sp) and allowed the refugees to travel toward India, Egypt, Mesopotamia (wise men from the east?)and other points by sea for the first time.
There appears to have been a large glacier across central Scandinavia, and that melted off circa 8,000 years ago. That's when we find the first human penetration to the Arctic Ocean shorline in Europe.
5,000 years ago we have the drying of the Sahara, and that, in turn, brought on cooler climate worldwide, and reduced rainfall further East in the Fertile Crescent, the Indus, etc.
This later cooling dry period is not associated with any serious change in ocean levels although it is certainly associated with temperature changes.
So, we might ask "did anybody write about this at the time", and, lo and behold, it would seem that they may have done so, although probably not contemporaneously. Many of the first of the ancient Sumerian cunuiform texts contained stories about folks in the far North encountering what the later Scandinavians called "Bifrost Giants", that is, glaciers, that moved in and scooted them away from the area. Folks with a taste for mysticism and a belief in advanced ancient civilizations have read all sorts of meaning into those stories.
Interestingly enough, the Sumerians who built some of the first large cities were not agriculturalists. Instead, they were seasonaly migratory herdsmen.
The Japanese of that time invented ceramics, village life, etc., the very essence of civilized life anywhere, and yet they never domesticated plants. Instead, their temperate zone forests were so plentiful they could devote time to technology while continuing to hunt and gather ~ much like the Sumerians far to the West.
BTW, the Japanese never developed a writing system. That was brought in by the Buddhists in the 6th century AD.
All of which is to say that I suspect "drying spells" had little or nothing to do with the growth of civilization.
Oppenheimer says:"...The third cold dry period was interrupted suddenly around 8,000 years ago by an event which, although only discoverd in the last decade, has been described as 'possibly the single largest flood in the last two million years."
Might have ~ it wouldn't have taken much. However, that's a major earthquake zone and gradually all the land on both sides of the straits is going to get ground up and turned into so much disagreggated schist!
During the periods of Glacial Maximum, Antarctica is completely covered by ice 2 or more miles thick. The ice shelf extends out hundreds of miles in all directions.
When the level of insolation becomes sufficient, this massive chunk of ice begins to melt.
Although we usually imagine the meltdown as being similar to that which occurs in North America and Asia, with a gradual melting from top to bottom, and the creation of massive waterfalls that persist of centuries (SEE: Turkey Run State Park near Crawfordsville, Indiana for an example of one which is presently visible ~ sans all the ice), the Antarctic complex may melt such that it forms an immense bowl ~ a persistent mile high ice perimeter, a two mile high central core, and a moat of meltwater surrounding the core.
The exterior wall would be kept colder than the interior by the very cold Cyclonic Winds at 40 degrees South (SEE: Roaring 40s - latitudes between 40°S and 50°S, the wind is not stopped by large landmasses).
Eventually enough melt water would accumulate that the inside of the surrounding wall would weaken. Finally, the wall would break and be pushed off the continental masses into the Antarctic ocean by the mass of melt water to the South.
This would create an incredible splash, followed by enough water to raise the ocean woldwide hundreds of feet!
The splash would then propagate itself as a mile high tsunami of worldwide proportions and lay waste to every intervening landmass to the North.
You'd have to be up in the mountains, in North Central Asia, or in the Congo basin to escape death and destruction.
The later flooding of the Black Sea basin would be peanuts compared to this.
Homo Sapien Sapiens have only been around for 100,000 years.
I imagine it took 90,000 years or so for population growth to kick in so that our intelligent-on-a-much-different-level ancestors could develop agriculture, cities etc.
Something like that.
"The splash would then propagate itself as a mile high tsunami of worldwide proportions and lay waste to every intervening landmass to the North."
"You'd have to be up in the mountains, in North Central Asia, or in the Congo basin to escape death and destruction."
"The later flooding of the Black Sea basin would be peanuts compared to this."
Yup. Earthquakes, volcanos and tsunamis to create enough flood stories to last to the present.
Curiously, the Tibetans have flood myths of the 'mountain topping variety' which lead some to think they may have migrated from some of the islands that were affected by huge tsunamis in that period. (The floods won't get them where they are now though)
Small rockslides just offshore in North San Diego County (Vista/Oceanside/Carlsbad) create small tsunamis that leave what are locally called "lagoons". Some of them are 10 to 15 miles inland.
That's small stuff. A mile high wall of water is a whole 'nuther thing!
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