Science-Technology
See other Science-Technology Articles
Title: Another global warming catastrophe: the Sahara Desert is getting greener [Greenland too]
Source:
HotAir
URL Source: http://hotair.com/archives/2015/06/ ... ara-desert-is-getting-greener/
Published: Jun 6, 2015
Author: Jazz Shaw
Post Date: 2015-06-06 10:11:12 by Tooconservative
Keywords: None
Views: 2071
Comments: 13
So the desert was originally created around six thousand years ago under this theory. (Clearly caused by the hydraulic fracturing taking place in the Garden of Eden. Darned industrialist snakes…) But now the warmer temperatures are causing more rain at the edges of the desert? The subject is endlessly fascinating. Over the years I’ve heard all sorts of theories being tossed out in the scientific community regarding the planet’s biggest, baddest desert. One of the most recent ones – and for some reason I thought this was generally accepted, but perhaps not – is that the planet’s orbital tilt drifts over time. Around the same time period they’re talking about in this article, the tilt began to change, shifting the planet into a less inclined tilt from then until now. “Additionally, the Earth had its closest approach to the Sun in the northern hemisphere (with) summer in August,” Schmidt said. “Today, that closest approach is in January. So, summertime in the north was warmer back then than it is now.” Earlier theories speculated that there was a growing “rain shadow” effect caused by the continually rising Himalayan Mountains, disrupting weather patterns and stopping the rainfall in some areas. Still other have said that eccentricities in the earth’s orbit around the sun (a different consideration than the orbital tilt) have periodically thrown things off kilter in either direction which also contributed to the growth or recession of major deserts. In either event, even if we can’t nail down exactly what’s causing it and to what degree the effects are felt, this must at least be some good news for farmers and herders in Africa. Party on, folks. Poster Comment: This story is actually quite fascinating and it obviously has something to do with changes in the climate, but just how to explain it all remains a subject of contention. You would think that increasing temperatures would make things worse in the deserts of the world, but in a rather counterintuitive instance of planet watching, it appears that the Sahara desert may actually be shrinking. A few thousand years ago, a mighty river flowed through the Sahara across what is today Sudan. The Wadi Howar—now just a dried-out riverbed for most of the year—sustained not just fish, crocodiles, and hippopotamuses, but also agriculture and human settlement. As late as 1,000 B.C., a powerful fortress stood on its shores. But then the Sahara dried out, turning from a green savannah into an inhospitable desert. The culprit: climate change. According to desert geologist Stefan Kröpelin, who has studied geological data for the eastern Sahara going back 6,000 years, the desert spread as temperatures dropped. Global cooling meant that the air had less capacity to hold moisture from the oceans, leading to fewer rains and more arid climes.
Now, that same process is happening in reverse. As temperatures rise, the Sahara and other dry areas are greening on the edges. “I’ve been studying the Sahara for 30 years and can definitely say that it’s getting greener,” says Kröpelin, who specializes in desert archaeology and climate history at the University of Cologne. Where there used to be nothing but desert, he says, there is now not just grass but shrubs and acacia trees–and he has the photos from 30 years of extensive field study to prove it. “The nomads are taking their camels to graze in areas where they’ve never been able to graze before.” Satellite data showing more green on the southern edge of the Sahara also bear him out. “There are always winners and losers if weather patterns change,” he says. “But as a general rule, warmer temperatures inevitably mean that the air picks up more moisture from the oceans, which will lead to more rainfall. If you look at the geological records in the Sahara, there have been repeated periods where the Sahara was greener when temperatures were warmer than today.”The widely-held belief is that the Sahara dried up due to a change in the Earth’s orbit, which affects solar insolation, or the amount of electromagnetic energy the Earth receives from the Sun. In simpler terms, insolation refers to the amount of sunlight shining down on a particular area at a certain time, and depends on factors such as the geographic location, time of day, season, landscape and local weather.
Climate scientist Gavin Schmidt, of NASA’s Goddard Institute for Space Studies, explained that around 8,000 years ago, the Earth’s orbit was slightly different to how it is today. The tilt changed from around 24.1 degrees to the present-day 23.5 degrees.
Post Comment Private Reply Ignore Thread
Top • Page Up • Full Thread • Page Down • Bottom/Latest
#1. To: TooConservative (#0)
So if there is global warming, we're simply returning to the way it was a few thousand years ago. As I've asked many times, how do we know we're not headed to the global temperature we should be at?
"A few thousand years ago, a mighty river flowed through the Sahara across what is today Sudan." So if there is global warming, we're simply returning to the way it was a few thousand years ago. As I've asked many times, how do we know we're not headed to the global temperature we should be at? I believe that we may be headed to the global temperature we should be at. Phoenix had rain yesterday for the first time in history on June 5. A rainfall record was set with .03 inches.
Flash flood.
Not quite. I am sitting by the tennis court with my laptop and drinking tea waiting for the weekend lawn attendant to squeegee it. The temperature here is 75, which is unusual. June is always one of our hottest months. TG for global warming...."It's a Beautiful Day in the Neighborhood." We do get some heavy runoff, but it stays in the Indian Bend Wash.
You bum... get your senior citizen ass over to my back yard and help with the beautification of my yard. Scratch that... I'm gonna can the whole project and grow a weed garden all over my property, devalue my neighbors properties and hope Free Thought Project will do an article about how much a victim I am when the township comes over and tickets me. lol Ok, since I'm not an anarchist, back to work I go. Every society gets the kind of criminal it deserves. What is equally true is that every community gets the kind of law enforcement it insists on. Robert Kennedy
What is it you Arizonites say when it's hot?
I have been outside here when it was 122 degrees. This "Arizonite" said: "Self, get your ass back inside."
Interesting tidbit, considering the article. Yet California may be returning to a desert configuration. NYT: By WILLIAM K. STEVENS BEGINNING about 1,100 years ago, what is now California baked in two droughts, the first lasting 220 years and the second 140 years. Each was much more intense than the mere six-year dry spells that afflict modern California from time to time, new studies of past climates show. The findings suggest, in fact, that relatively wet periods like the 20th century have been the exception rather than the rule in California for at least the last 3,500 years, and that mega-droughts are likely to recur. The evidence for the big droughts comes from an analysis of the trunks of trees that grew in the dry beds of lakes, swamps and rivers in and adjacent to the Sierra Nevada, but died when the droughts ended and the water levels rose. Immersion in water has preserved the trunks over the centuries. Dr. Scott Stine, a paleoclimatologist at California State University at Hayward, used radiocarbon dating techniques to determine the age of the trees' outermost annual growth rings, thereby establishing the ends of drought periods. He then calculated the lengths of the preceding dry spells by counting the rings in each stump. This method identified droughts lasting from A.D. 892 to A.D. 1112 and from A.D. 1209 to A.D. 1350. Judging by how far the water levels dropped during these periods -- as much as 50 feet in some cases -- Dr. Stine concluded that the droughts were not only much longer, they were far more severe than either the drought of 1928 to 1934, California's worst in modern times, or the more recent severe dry spell of 1987 to 1992. In medieval times the California droughts coincided roughly with a warmer climate in Europe, which allowed the Vikings to colonize Greenland and vineyards to grow in England, and with a severe dry period in South America, which caused the collapse of that continent's most advanced pre-Inca empire, the rich and powerful state of Tiwanaku, other recent studies have found. . . .
There is no magic temperature and, even if you could determine one, it wouldn't last. It is a climate after all. People think somehow it is a static thing. Well, that is against the entire notion of climate.
Interesting,thanks.
"During the last 10,000 years, data point to four periods of “mega-drought”— one lasting nearly 3,000 years." Try growing/husking Corn in that climate.
Good info good thread. Thanks.
Truly my soul waiteth upon God: from him cometh my salvation. He only is my rock and my salvation; he is my defence; I shall not be greatly moved. (Psalm 62:1-2)
"A few thousand years ago, a mighty river flowed through the Sahara across what is today Sudan."
#2. To: misterwhite, TooConservative (#1)
(Edited)
#3. To: Gatlin (#2)
"A rainfall record was set with .03 inches."
#4. To: misterwhite (#3)
(Edited)
#5. To: Gatlin (#4)
I am sitting by the tennis court with my laptop and drinking tea waiting for the weekend lawn attendant to squeegee it.
#6. To: Gatlin (#4)
#7. To: misterwhite (#6)
(Edited)
What is it you Arizonites say when it's hot?
#8. To: Gatlin (#2)
Phoenix had rain yesterday for the first time in history on June 5.
Severe Ancient Droughts: A Warning to California
Published: July 19, 1994
#9. To: misterwhite (#1)
As I've asked many times, how do we know we're not headed to the global temperature we should be at?
#10. To: TooConservative (#8)
#11. To: TooConservative (#9)
(Edited)
http://netnebraska.org/article/n...ought-nebraskas-sandhills
#12. To: TooConservative (#0)
#13. To: TooConservative (#8)
Top • Page Up • Full Thread • Page Down • Bottom/Latest
[Home] [Headlines] [Latest Articles] [Latest Comments] [Post] [Mail] [Sign-in] [Setup] [Help] [Register]