Skip to comments.Ancient Drought And Rapid Cooling Drastically Altered Climate
Posted on 06/24/2009 11:06:18 AM PDT by tricky_k_1972Ancient Drought And Rapid Cooling Drastically Altered Climate
by Staff Writers
Columbus OH (SPX) Jun 23, 2009
Two abrupt and drastic climate events, 700 years apart and more than 45 centuries ago, are teasing scientists who are now trying to use ancient records to predict future world climate.
The events - one, a massive, long-lived drought believed to have dried large portions of Africa and Asia, and the other, a rapid cooling that accelerated the growth of tropical glaciers - left signals in ice cores and other geologic records from around the world.
Lonnie Thompson, University Distinguished Professor of Earth Sciences at Ohio State University, and researcher with the Byrd Polar Research Center there, outlined the puzzle to colleagues at the Chapman Conference on Abrupt Climate Change. The meeting was sponsored by the American Geophysical Union and the National Science Foundation.
Thompson, who has led more than 50 expeditions to drill cores through ice caps on some the highest and most remote regions of the planet, believes that the records from the tropical zones on Earth are the most revealing and that the last 1,000 years provides the best clues.
"I would argue that the last 1,000 years are most critical from the perspective of looking at the future," he said
The first of the two tantalizing events is apparent in an ice core drilled in 1993 from an ice field in the Peruvian Andes called Huascaran. Within that core, they found a thick band of dust particles, most smaller than a micron in diameter, the concentration of which was perhaps 150 times greater than anywhere else in the core. That band dated back to 4,500 years ago.
"Dust that small can be transported great distance - the question is where did it come from?" Thompson said. "I believe that record accurately reflects drought conditions in Africa and the Middle East and that the dust was carried out across the Atlantic Ocean by the northeast trade winds, across the Amazon Basin and deposited on the Huascaran ice cap.
Thompson said that other records, including an ice core taken from glaciers atop Tanzania's Mount Kilimanjaro, also show a dust event dating to a time when there was substantive drying up of lakes in Africa. He said that it is the only such huge event that the ice core records show for the past 17,000 years.
The other mystery surrounds a major cooling event that Thompson believes happened about 700 years earlier. During a 2002 expedition to the Quelccaya ice cap in Peru, the largest tropical ice field in the world, Thompson and colleagues discovered patches of ancient wetland plants that had been exposed as the edge of the ice cap retreated. When carbon-dated, the plants were shown to be 5,200 years old, meaning that they had been covered, and preserved, by the ice for the last 52 centuries.
Since then, recent expeditions have located similar patches of plants revealed by the ice's retreat. All date back to at least 5,200 years ago and some as much as 7,000 years ago.
"This means that sometime around 5,200 years ago, there was a rapid cooling event in this region and the ice expanded shielding the plants from damage and decay," Thompson said.
Other records from around the world seem to support the idea of a cooling event at this time. Divers in Lake Tahoe, Nevada, found nearly two dozen ancient tree trunks preserved at the lake's bottom. Wood samples from the trunks date back 5,200 years and geologic records show the current lake levels have remained steady since that point in time.
Thompson also pointed to the timing of past climate changes in South America and the rise and fall of early cultures in the region.
Evidence from the ice cores from Quelccaya suggest that cultures might have grown during wet periods in the Peruvian Highlands and waned when the climate became drier. Conversely, cultures appeared to grow in the country's coastal regions when the climate became wetter and were lost as drying increased.
"This suggests that there could have been persistent climate periods that allowed these cultures to flourish under certain conditions and fail under others," he said.
Thompson leads a new expedition next week to two new sites in the Andes in hopes of drilling cores that will show more detailed records of both events.
The evidence that researchers have, both from ice cores and from the rapid retreat of glaciers, show that high-altitude ice fields reflect similar changes that are currently visible all across the temperate portions of the globe.
"The ice caps are sentinels of the earth's overall climate," he said. "And the data shows that at all of these sites, the rate at which the ice is vanishing is accelerating.
"To me, these are indicators that these areas are already being adversely impacted by changes in our current climate."
Wasn’t there an impact event in southern Iraq about this time?
There were too many HumV’s back then.
“I would argue that the last 1,000 years are most critical from the perspective of looking at the future,” he said
I would argue you’re a tunnel visioned idiot.
“The ice caps are sentinels of the earth’s overall climate,” he said. “And the data shows that at all of these sites, the rate at which the ice is vanishing is accelerating.
“To me, these are indicators that these areas are already being adversely impacted by changes in our current climate.”
The earth’s average global temperature has been slowly, gradually getting warmer since the end of the “little” ice age. The last 100 years do not represent a change, but a continuation of a longer trend.
However, some scientists believe that we may now be at the peak of that trend (isn’t always hottest, or coldest just before the cycle trends in the opposite direction) and we may be heading into a cooling trend.
(1) is insufficient to force heating/cooling trends; and
(2) is not a zero-sum factor (not only adds to the insulation but changes the climate dynamics in ways that also contribute to cloud formation, precipitation AND cooling); and
(3) because of (2) it has a finite, not infinite range in the level it will accumulate in the atmosphere; and
(4)because (3) is ignored in the ICCP climate “model”, at the root if it’s calculations, the model’s results have never been correct.
Amazing how rapid evapouration of water after a worldwide flood event could result in perceived drought conditions as well as a large drop in temperature.
Since the last glacial period ended about 10,000 years ago, this doesn’t seem that odd.
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Just goes to show WE ARE VERTUALLY POWERLESS IN THE FACE OF NATURE.
(I would like to see a little cooling down here in Texas HOT, HOT...)
No sweat! If it hadn’t been for all your posts and pinglists, I would still be lost on most of this. It’s good to give back just a little...
I’m kinda partial to Robert Felix’s theory that undersea volcanoes in the Pacific heat that ocean and cause “El Nino” weather effects.
And I also admire Henrik Svensmark’s recent research showing that periodicly the magnetic field strength of our sun decreases and this allows more cosmic rays (charged particles) to penetrate our atmosphere. These high speed particles hit atoms and molecules in our atmosphere and ionize them in a catalytic way via electron tranfer and cause the formation of low lying clouds, as water molecules are attracted to the newly ionized air molecules (like seeding a cloud).
More of these clouds over land causes more rain (and floods) or snow (and glaciers) in certain areas. More of these clouds over the ocean cools the evaporation process that leads to monsoons, and causes more droughts in certain areas.
Here’s an article describing the Iraq crater: http://www.independent.ie/world-news/devastating-meteor-probably-destroyed-ancient-civilisations-325265.html
Ping me if you find one I've missed.
GoogleEarth satellite image of Umm al Binni Lake in southern Iraq The ruler line represents a distance of two miles.
...and the seven judges of Hell, the Annunaki, raised their torches, lighting the land with their livid flame. A stupor of despair went up to heaven when the god of the storm turned daylight into darkness, when he smashed the land like a cup. One whole day the tempest raged, gathering fury as it went, it poured over the people like tides of battle; a man could not see his brother nor the people be seen from heaven. Even the gods were terrified at the flood, they fled to the highest heaven, the firmament of Anu; they crouched against the walls, cowering like curs.
That was 4200 years ago.
The glimmering of a "solution" to both the Gorbal Warming, AND the DPRK problems: Drop a similar sized impactor on Pyongyang
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