Posted on 10/03/2008 11:55:57 AM PDT by SunkenCiv
Reconstructing the climate of the past is an important tool for scientists to better understand and predict future climate changes that are the result of the present-day global warming. Although there is still little known about the Earth's tropical and subtropical regions, these regions are thought to play an important role in both the evolution of prehistoric man and global climate changes.
New North African climate reconstructions reveal three 'green Sahara' episodes during which the present-day Sahara Desert was almost completely covered with extensive grasslands, lakes and ponds over the course of the last 120.000 years. The findings of Dr. Rik Tjallingii, Prof. Dr. Martin Claussen and their colleagues will be published in the October issue of Nature Geoscience.
Scientists of the... Center for Marine Environmental Research in Bremen... and the Alfred-Wegener-Institute in Bremerhaven... studied a marine sediment core off the coast of Northwest Africa to find out how the vegetation cover and hydrological cycle of the Sahara and Sahel region changed. The scientists were able to reconstruct the vegetation cover of the last 120.000 years by studying changes in the ratio of wind and river-transported particles found in the core...
The scientists explain these periods by an increase of the precipitation that resulted in a much larger vegetation cover resulting in less wind dust and stronger river activity in the Sahara region...
The computer model simulation shows three periods with an almost completely vegetated Sahara at the same time as seen in the geological record. This supports the interpretation of geologists and, in turn, demonstrates the value of computer model results. Additionally, the computer model indicates that only a small increase in precipitation is sufficient to develop a vegetation cover in the Sahara.
(Excerpt) Read more at sciencedaily.com ...
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There’s a joke that goes around the PNW that goes:
“A logger was being interviewed for a job as a logger by a large tree farm. He was asked where his last job was. He replied that he was a logger in Saudi Arabia. The interviewer laughed and said ‘there are no trees in Saudi Arabia, it’s a desert’. The logger agreed and said ‘yeah, - now!”
PNW humor ...
Wonder how a Green Sahara would affect the Cape Verde hurricane phenom?
Guess I should read before I type?
Veeeery interesting!
Pity we aren’t heading for global warming for the next few decades. Yesterday’s solar flux values were:
Flux Density Values in sfu for 23:00 on 2008:10:02
Julian Day Number : 2454742.447
Carrington Rotation Number : 2075.228
Observed Flux Density : 0065.6
Flux Density Adjusted for 1 A.U. : 0065.7
URSI Series D Flux, Adj. x 0.9 : 0059.1
Computer model simulations for the future suggest an expansion of the vegetation cover in the Sahara Desert if human-driven climate change leads to aggressive global warming. However, it is difficult to conclude that the Sahara will actually become greener than it is today, as the simulations do not account for the influence of human activity in this area.
So this study suggests that Global Warming will make the Sahara Dessert turn into a parklike savannah. Notice how they hid this little fact.
The green Sahara episodes correspond with the changing direction of the earth’s rotational axis that regulates the solar energy in the tropical Atlantic Ocean.
I wonder if a scientific consensus exits regarding these geophysical data? Chances are there are many peer-reviewed papers.
Can temperate conditions in the Sahara actually be the more natural (i.e. the north polar glacier cap is minimal)? As many old sci-fi tales ended, I shall do the same. "Time will tell."
Um, do you want to give the Solar Flux for Dummies version for us, uh . . . dummies? ;-)
so the sahara has had green periods 3 times over the last 120000 years...??...and they say global warming is man made from the industrial age....might there be some truth to the earth going through cycles of warming and cooling naturally...??...
Sounds right to me .... like what ended the last ice age and why wasn’t there global warming during WWI and WWII???? Lots of stuff being blown up then .....
There’s strong evidence that cattle and dogs were domesticated in the Sahara during its most recent greening, and that the most recent desertification was the impetus behind the urbanisation of the Nile valley.
I’ve thought that the rapidity of the most recent desertification, which may have unfolded in less than a century, might have been the basis of the story of the expulsion from the garden of Eden, with its missing rivers and cherubim with swords of fire.
No problem.
“Solar Flux” is a measurement of the strength of the sun’s magnetic field and is measured via a radio telescope.
The magnetic field’s strength is, like sunspot activity to which it is closely linked, an indicator for the brightness of the sun.
When the value is high, when there are many sunspots, the sun cranks out a little extra energy and the result is that Earth heats up too.
But when the value is low (the 64-68 range for solar flux is as low as has been observed), when there are no sunspots, the sun is slightly dimmer and the result is global cooling.
Right now the sun has been unusually quiet as Solar Cycle 23 has come to its end but Solar Cycle 24 has not started. Really, there has been no global warming since around 1998 and the present trend is for cooling.
For some months I was running a “Global Cooling Watch” and there is a kind of a summary post here: http://www.freerepublic.com/focus/f-news/1969680/posts?q=1&;page=101#120
Lots of good discussion in that thread.
I’ve been rooting to have the coming minimum called the “Gore-Hansen Minimum” in honor of two of the most shameless hucksters for man-made global warming.
Thanks!
LOL! Great idea -- if you get up some sort of petition, I'll be happy to sign! ;-)
Thanks for the info and the link!
This would accomplish:
1) more moisture going westward from evaporation and thus creating a green belt area to the west of the depression.
2) lower the sea level abit
3) create the possibility of an inland, central Africa port and thus improve the economic conditions for western Egypt,
So - has Buffet been buying real estate in the Sahara?
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