Saturday, July 30, 2011

Climate Change 4200 Years Ago

No one has yet answered why the weather patterns suddenly shifted - and stayed shifted for some 300 years!  Our scientists know that this happened, and our archaeologists have uncovered the resulting devastation.  Civilizations were destroyed.  People and animals starved to death when the rains were cut by as much as 50% in almost all areas of the globe.  In these days when a few years without rain can cost billions of dollars in crop losses, send the price of food sky high and kill hundreds of thousands (as in Somalia, for instance), what would we do if the rains were cut by 30 to 50% for 300 years?  What would happen to Africa?  China?  India?  The United States? 

From Science at
Ancient city survived as civilizations collapsed
Archaeologists involved in arduous excavation want to know, 'How did that happen?'
updated 7/29/2011 1:01:26 PM ET

As ancient civilizations across the Middle East collapsed, possibly in response to a global drought about 4,200 years ago, archaeologists have discovered that one settlement in Syria not only survived, but expanded.

Their next question is — why did Tell Qarqur, a site in northwest Syria, grow at a time when cities across the Middle East were being abandoned? [Oh please, people who were fleeing drought-destroyed fields, towns and city-states had to live somewhere where there was a reliable water supply!]

"There was widespread abandonment of many of the largest archaeological sites and ancient cities in the region and also large numbers of smaller sites," said Jesse Casana, a professor of anthropology at the University of Arkansas. "At Tell Qarqur and probably at other sites also in the Orontes River Valley, where our site is located, (settlement) continues, and in our case, seems to have probably broadened (during that time)."

Casana and Boston University archaeologist Rudolph Dornemann discovered mud-brick homes beyond the city's fortification walls, suggesting the area was thriving.

"It seems like there is an intensively occupied core and fortified area, and more dispersed settlement surrounding it," said Casana. One of the team members, Amy Karoll, presented the research at the 76th annual meeting of the Society for American Archaeology in April.

Digging up history
Tell Qarqur was occupied for about 10,000 years, between 8,500 B.C. and A.D. 1350. While excavations have taken place off and on for nearly three decades now, only a small portion of the city has been excavated so far. The long history of the site makes digging down to the 4,200-year-old remains difficult. To compensate, the team has used Ground Penetrating Radar to help map structures beneath the surface.

One of the most interesting excavated finds is a small temple or shrine made out of stone that also dates back 4,200 years. "It's a small stone building with a whole series of plastered basins inside the building that were used probably in some kind of libation ritual," said Casana.

The team also found large standing stones, bones from baby sheep, cult stands used for incense and decorative figurines, some of which are now on display in a local museum.

Global climate change
Environmental data gathered from numerous sources, including ocean sediment cores and plant remains, suggests that there was a climate event that rocked the Middle East and much of the planet 4,200 years ago.

"At 4,200 years ago, there was an abrupt climate change, and abrupt drying, and abrupt deflection of the Mediterranean westerly winds that transport humid air into the eastern Mediterranean region," Harvey Weiss of Yale University told LiveScience.

Weiss has been researching the phenomenon, working with other scholars to figure out how broad an event this was and what its effects were.

"That deflection of those winds reduced the annual precipitation across western Asia for about 300 years," he said, with rainfall being reduced somewhere between 30 percent and 50 percent. This meant that cities in the Middle East that depended on rain-fed crops had a difficult time surviving. The intense drought extended nearly globally, Weiss noted.

Along with the Mesopotamian and eastern Mediterranean societies that met their demise, Old Kingdom Egypt, a civilization that built the Great Pyramids, collapsed. "A different weather system reduced the flow of the Nile River at the same period so the Nile was affected," Weiss said.

Casana cautioned that not all scholars are convinced that climate change was the main cause for the collapse of cities in the Middle East. [Really?]

"It's a pretty thorny question," Casana said.

Some researchers "simply don't like the sort of one-to-one causal story that that kind of narrative tells, in which the rain stopped falling and everybody died," he said, adding that the way people were farming and using the land may also have played an important role. [But not enough of a role to shift global rainfall patterns!  Come on!]

Another factor is the shaky political stability that large states sometimes endure. "There are other scholars who simply think that the decline of these civilizations, at that time, is kind of part and parcel of the story of civilization itself," Casana said. [Well of course political instability of already shaky regimes would have resulted when people were starving to death!]

Why did Tell Qarqur survive?
The question now is why Tell Qarqur is different. Why did the site survive and expand while so many others collapsed? Casana said that until more excavation is done, the jury will still be out as to why.
Weiss believes that the Orontes River, on which the city is located, is the key to answering this question. He pointed out that other archaeological sites on the river, including Qatna and Nasriyah, also appear to have prospered during this time of collapse.

"The Orontes River is fed by a huge underground chamber of water, which is called a Karst," Weiss said. "That huge underground source of water continued to flow and to feed the Orontes River during this period when rainfall was diminished."

There are other questions. Before the collapse hit, Tell Qarqur was within the sphere of influence of a powerful kingdom known as Ebla. That kingdom was destroyed sometime prior to 4,200 years ago. This likely changed the way the city was governed and managed, something that future excavations may reveal.

"What happens to the political realities of the community at Qarqur I don't know," said Casana. "I'm sure there must have been some change."

Weiss said that the discovery of cities that grew during climate collapse offers a new frontier for archaeologists and scientists to investigate.

"I think that the early bronze four (the scientific name for this period of collapse) culture of the Orontes is only just now emerging for our attention and that it's going to provide an extremely interesting example of cultural growth in unique environments during this period," he said.
Dudes, start looking for other areas where it is known that such Karsts, and other "guaranteed" sources of fresh water, existed 4,200 years ago. 

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