Study Explains Why Sahara Desert Turns Green Every 21000 Years

Hello and welcome! My name is Anton and in this video, we will talk about discoveries about the cycle in the Sahara desert
Links:
#sahara #earth #humanity

0:00 Sahara cycles
1:10 Evidence for wet Sahara
2:55 More evidence from caves
4:30 Thorium deposits provide first answers
5:20 Milankovich cycles
6:05 Shrimp and sea monkeys!
6:55 Migration and Sahara
7:55 Other effects from glaciation and the future of Sahara

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[janerkenbrack]

I'm going to buy a bunch of land in the Sahara and everyone will be laughing at me. But in 15, 000 years, I'll be the one who is laughing.

[LuciFeric]

I live in the high desert USA. It looks quite barren, but when it rains the desert becomes a meadow. All those seeds and roots are just waiting patiently to bloom.

[alexiere]

One of the reasons I wish I was immortal just to see the world change.

[danoblue]

I've been in the eastern Sahara (Egypt) and the northwestern Sahara (Morocco) and it is a fascinating place. I live on the coast of Peru, which is also a desert, and it also has its beauty. A small error--the driest desert is not the Sahara but the Atacama, which I've also seen. I also remember how rains in San Diego in 1977, where I used to live, transformed the Anza-Borrego desert into a green meadow with lots of wildflowers. Deserts are fascinating places

[WaterShowsProd]

Another interesting and important thing about The Sahara Desert is that winds blow the sands clear across The Atlantic Ocean and fertilise The Amazon in South America, otherwise there wouldn't be enough nutrients to keep that ecosystem thriving. My sister-in-law did a field expedition off the coast of Africa and they needed to sweep the sand off the boat every day, otherwise it would become weighed down with sand. Another example of the interconnected nature of the planet.

[warrentreadwelljr.treadwel]

What I really love is all those older maps showing rivers, lakes, streams, and cities located in the Sahara. We know none of those existed during the time the maps were drawn. Since those were copied from older maps, it makes me wonder how far back in history were those maps first drawn. Our first cities and towns post date to when the cities and towns had been buried by sand for thousands of years.

[zhain]

ive had people call me an idiot because ive talked about this. people have a really limited view of what the world was and what it can be

[Sontus]

You may also see some of the similar results in the southwestern USA deserts near the town of Indio, California - 7-8, 000 years ago, what is now a high desert was very lush and covered with large lakes.

[MrJudge]

Another brilliant explanation of what happened in the past. Thanks Anton. ( and all the people behind this) Thank you. Great topic to explain my students. :-)

[deathroll]

Just imagine what is under that sand. So much of human history is locked in there.

[vaakdemandante]

Wow, the shrimps that wait for the rain buried deep in the sand are straight up a sci-fi horror theme.

[TexanMiror]

Absolutely fascinating, especially because this seems like, as you mentioned, a central mechanism for how and why humans spread across Earth, and evolved in the way they did. Yet, so few people know about these cycles.

[juaquinfuentesjara]

small nitpick, the Sahara is certaintly the largest desert, but it also certaintly isnt the driest one, that would be the much smaller but a lot drier Atacama desert

[johnteevins]

As a stroke victim living a rather sad and severely limited intellectual life i have to say...thank you wonderful person.

[annezwart]

Incredibly interesting. Thank you for making these informative videos!

[crabby]

We have known that at least parts of the Sahara were very fertile in the roman period as some called it the breadbasket of the empire. There are also Egyptian empire cities out in the desert that got abandoned when the desert encroached on them.

I saw a TV program ages ago where an expedition went out In to the Sahara to investimate the basis of those cave paintings of humans and animals way out in the desert, including giraffes (cave paintings in Libya iirc). What they eventually found inbetween some outcrops of rock were some all year pools that were originally parts of rivers before it all dried out. How did they know they were remnants of rivers I hear you ask? The answer is that they found a small population of small nile crocodiles in some of the larger pools. They had managed to survive by gradually reducing size over the generations. This was a stunning revalation that proved that large parts of the Sahara had once been much wetter than now and that herds of other animals did indeed live locally.

[robertfindley]

Interesting as always! As I understand it, the Atacama Desert in Chili is the driest desert on Earth.

[ArtisticlyAlexis]

Ha! This is exactly what I was researching for a novel I'm writing about a seemingly utopian society in the future set partly in a green Sahara! Thanks!

[aurelspecker]

There is also a potential that we green the Sahara by accident.
There was a study, that showed, if we fill the sahara with solar panels, the albedo is decreasing so much, that the weather patterns change to a degree that it rains more. As soon as that starts, it starts greening, the albedo decreases further with the sand covered by dark plants. And consequently, the rain eats it's way inside to the sahara.

Sure, these systems are super complicated and there are a lot more parameters. But the potential is definitely there.

PS: Having a green sahara sounds very good, but it wouldn't stop climate change, quite the opposite, the lower albedo would even increase the energy input from the sun and further increase temperature.

[RazvanMihaeanu]

*5:35** Anton, that's wrong!* I think you want to say 2 degrees of "axial tilt" (with a mean period of roughly 41 000 years).
Because it's 1 degree of precession every 72 years or so (almost), thus the entire 360 is made in 25772 years (this is called "The Great Year" - the ancient astronomers believed - incorrectly - that it was exactly 72 years/"virgins" for 1 degree, thus resulting a total of 25 920 years).
The 148 years difference (25772 v. 25920) was corrected by Dionysius Exiguus about 15 centuries ago, when he also divided this Great Year in 12 zodiacal signs/eras (25772 / 12 = 2147 years and 8 months per Era).
Thus the corrected 148 years at the beginning of Pisces "Christian Era" (ending the Aries "Jewish shofar - ram's horn" Era... which previously - thanks to Moses - ended the "Ancient Egypt Taurus/Bull Era") started in what we know today as... *YEAR 1 - ANNO DOMINI*
...and now we are getting close to the Aquarius Era...the "New Age".