Posted on 12/21/2010 10:03:52 AM PST by LucyT
The Sahara, the world's largest desert, was once fertile grassland. This fact has been common knowledge in the scientific community for some time, but scientists are still grappling with historic data to determine whether that transition took place abruptly or gradually.
At the European Geosciences Union General Assembly held in Vienna, Austria earlier this year, researchers presented new evidence showing that the eastern region of the Sahara desert, particularly the area near Lake Yoa in Chad, dried up slowly and progressively since the mid-Holocene period.
(Excerpt) Read more at physorg.com ...
Owl gore says different.
I ran across another idea once that at one time North America and South America were separated by a strait through which a large ocean current flowed.
When Central America rose, cutting off the current, the climate of Africa changed.
According to that particular article, the African climate change was what led to the evolutionary rise of homo sapiens.
This relates to the archaelogy work conducted at the dry lake west of the nile by a few hundred kilometers. The links below are from different historical eras.
http://news.discovery.com/earth/ancient-egypt-mega-lake.html
Sunkenciv pinged a thread discussing that lake recently.
Shuttle images reveal Egypt’s lost great lake
http://www.freerepublic.com/focus/chat/2636761/posts
· 12/03/2010 4:09:49 AM PST ·
· Posted by SunkenCiv ·
· 26 replies ·
· Science News ·
· Wednesday, November 24th, 2010 ·
· Alexandra Witze ·
Radar images taken from the space shuttle confirm that a lake broader than Lake Erie once sprawled a few hundred kilometers west of the Nile, researchers report in the December issue of Geology. Since the lake first appeared around 250,000 years ago, it would have ballooned and shrunk until finally petering out around 80,000 years ago... Since then, desert winds have eroded and sands have buried much of the region’s landscape, says Maxine Kleindienst, an anthropologist at the University of Toronto. But during next summer’s field season, she and her colleagues will be checking for ancient shorelines at the elevations...
older thread:
http://www.freerepublic.com/focus/chat/2579098/posts
The Lost City: A discovery in the desert could rewrite the history of ancient Egypt
Yale Alumni Magazine ^ | September/October 2010 | Heather Pringle
It was all those ancient Israelites and their SUVs. They parked them all close together and shifted the Earth’s orbit.
Ah the money quote:
‘For a long time, the belief was that the Earth’s tilt would change only insignificantly in the next century. However, recent research is suggesting that the effects of global warming—particularly the oceans—could cause a change in the Earth’s axial tilt. Scientists from NASA’s Jet Propulsion Laboratory say that the current melting of ice in Greenland is already causing the tilt to change at a rate of approximately 2.6 centimeters each year. They predict that his change could increase in the years ahead.’
Uh huh. Now global warming is causing tilt shifts in the earth.
Oh, but did you get to the punchline in the article?? The one that says that Global Warming and the rising oceans are actually going to CAUSE the earth’s axis to tilt, leading to MORE global warming? Face-palm.
Read Velikovski -'Worlds in Collision'. Now largely discredited but very interesting reading, and you never know, maybe he was on to something.
Obviously, they haven't heard of George W. Bush.
>>A change in the Earth’s orbit, many scientists believe, transformed the “Green Sahara” into what is now the largest desert on the planet.<<
No way! We all know it was the smoke from Cromagnon camp fires.
Did you ever see a top spinning around and suddenly it gives a big twitch then stabilizes again for a short time...
i think that ‘twitch’ would be quite a shcok if it happened to the spinning earth.
It would also explain a lot of things- like why we find landmarks 100 feet underwater that used to be cities, and sea life fossils on mountain tops
It’s almost like a ‘dry band’ that goes around much of the Earth. You can look at the Sahara on a global map, and nearly all the way around the planet, there is desert, across the Middle East, all the way around to the South Western US/Mexico. It varies some, but you can definitely see the pattern.
Second rate, second hand alarmism.
The article actually describes a difference in the phasing between perihelion and vernal equinox and changes in the tilt or obliquity of the earth’s rotational axis, which are all part of the familar Milankovitch Theory.
The article did talk about a 2.6 cm/year change in the earth’s tilt caused by melting of Greenland’s ice cap. This would produce a change in tilt of 0.000023 degrees per century. Compared to the 0.01 degrees per century due to astronomical torques, it’s in the friggin’ noise.
Saharan Shape Shifter
“Now global warming is causing tilt shifts in the earth.”
Well, that nullifies sceptics- deniers- who use Milankovitch periodic axial tilt to debunk Global Warming, or Global Cooling, or Global Catastrophic Climate Change or whatever today’s flavor of global socialism is.
Take your lefty lies somewhere else!
No one else wants them.
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