5000 years ago Sahara was a green landscape with lakes and rivers • Hacker News Board

Re: 5000 years ago Sahara was a green landscape with lakes and rivers

#51

Post by filoeleven » Mon, Sep 02, 2019, 3:30 PM UTC

moultano wrote: post #12

FillardMillmore wrote: post #9

Earlier quoted context omitted.

You beat me to it. I find this subject interesting but the platform of Twitter is incredibly ill-fitting for this. I've noticed recently more and more people doing long-form content on Twitter - I hope it's not a trend that catches on.

Being able to link and pass around the most interesting sentence (and associated media) as a unit separate from the rest (but keeping the original context attached) makes it much easier for things to spread. How often have you wanted to share an interesting paragraph from an article and been unable to link to it? Twitter threads are an awkward solution to this, but they're the best available.

> How often have you wanted to share an interesting paragraph from an article and been unable to link to it?

Never? If I’m linking something and I want to show some text copied from the article, I copy and paste it. Texts and email and HN and Facebook all support this...where are you sharing things outside of Twitter where this isn’t possible to do?

Re: 5000 years ago Sahara was a green landscape with lakes and rivers

#52

Post by singularity2001 » Mon, Sep 02, 2019, 5:46 PM UTC

parasense wrote: post #38

crooked-v wrote: post #33

Earlier quoted context omitted.

More broadly, the Middle East in general was once extraordinarily bountiful, but the cumulative effects of natural climate change and thousands and thousands of years of saltwater irrigation have unfortunately desertified much of the region.

Well yeah, and also considering that natural climate change was the most significant issue. Since the Pleistocene ice age ended around 11 thousand years ago, and ever since then the equatorial regions have changed dramatically. Coincidentally this is about the beginning of recorded history, or at least the parts recovered from antiquity. The regions around north Africa, the Arabian peninsula, etc... they all would ha…

Would the Sahara have turned into a desert without millennia of overgrazing and over-burning?

Re: 5000 years ago Sahara was a green landscape with lakes and rivers

#53

Post by singularity2001 » Mon, Sep 02, 2019, 6:35 PM UTC

jcranmer wrote: post #14

mcthrowaway123z wrote: post #5

Is this suggesting that modern civilization started with climate change? At the end, he points out that the occupants of these areas moved towards the coasts during the desertification. This would have been immediately preceding the establishment of the first Egyptian dynasty.

It's worth remembering that civilization was independently invented in several different places, at least in Mesoamerica, Peru, Egypt, Mesopotamia, Indus River, and China. Possibly more, as anthropology has tended to assume that cultural innovation is imported (or at least adapted) from elsewhere in the absence of evidence one way or the other. Climate change is presently believed to be a major catalyst to the develo…

At least for the Eurasian civilizations, the term 'independently invented' is easily falsified:

Metallurgy and chariots arrived in China from the west; Mesopotamia, Indus and Egypt were in very close contact. So much so, that the cultural artifacts of the epochs preceding the first dynasties are near identical (including building plans!) : https://raw.githubusercontent.com/wiki/pannous/hieros/susa-e...

Re: 5000 years ago Sahara was a green landscape with lakes and rivers

#54

Post by fred_is_fred » Mon, Sep 02, 2019, 6:54 PM UTC

JoeAltmaier wrote: post #49

adolph wrote: post #4

Changes in the earth's orbit known as its orbital precession, a change in tilt that cycles every 25,000 years, forced the African monsoon rains southward, and the Sahara became drier. https://en.wikipedia.org/wiki/Apsidal_precession https://en.wikipedia.org/wiki/Milankovitch_cycles

Um. Cut down all the trees and a forest has a hard time recovering. The Sahara is likely man-made. Like almost all deserts on Earth except Namibia and Australian which are millions of years old, the rest are mere thousands. Familiar story. America's Southwest used to be treed grasslands until overgrazing turned them to sand and wasteland.

I call bullshit. Where in the American Southwest was it treed grasslands until it was overgrazed? I've been through the whole region from west Texas to Arizona, NM, Colorado and the Oklahoma panhandle. There was certainly problems in some of those regions during the Dust Bowl, but your general statement reeks of fiction. Phoenix was never the Serengeti in any times where humans were grazing animals.

Re: 5000 years ago Sahara was a green landscape with lakes and rivers

#55

Post by aliswe » Tue, Sep 03, 2019, 6:03 PM UTC

JoeAltmaier wrote: post #49

adolph wrote: post #4

Changes in the earth's orbit known as its orbital precession, a change in tilt that cycles every 25,000 years, forced the African monsoon rains southward, and the Sahara became drier. https://en.wikipedia.org/wiki/Apsidal_precession https://en.wikipedia.org/wiki/Milankovitch_cycles

Um. Cut down all the trees and a forest has a hard time recovering. The Sahara is likely man-made. Like almost all deserts on Earth except Namibia and Australian which are millions of years old, the rest are mere thousands. Familiar story. America's Southwest used to be treed grasslands until overgrazing turned them to sand and wasteland.

It's not just a lack of trees. It's a lack of soil as well. And the temperatures are really unforgiving. Heard about al rub al khali, ie most of saudi arabia? Who cut down those trees you think?

I'm not saying overgrazing never happened, bit it was not nearly enough to explain the current desolation.

Re: 5000 years ago Sahara was a green landscape with lakes and rivers

#56

Post by aliswe » Tue, Sep 03, 2019, 6:06 PM UTC

aliswe wrote: post #55

JoeAltmaier wrote: post #49

Earlier quoted context omitted.

Um. Cut down all the trees and a forest has a hard time recovering. The Sahara is likely man-made. Like almost all deserts on Earth except Namibia and Australian which are millions of years old, the rest are mere thousands. Familiar story. America's Southwest used to be treed grasslands until overgrazing turned them to sand and wasteland.

It's not just a lack of trees. It's a lack of soil as well. And the temperatures are really unforgiving. Heard about al rub al khali, ie most of saudi arabia? Who cut down those trees you think? I'm not saying overgrazing never happened, bit it was not nearly enough to explain the current desolation.

Also, on the otger hand, check out the al bayda project in saudi arabia, the site of which was a forest just 100 years ago (according to the villagers)