It's all over but for the sweating?

[Arragonis]

Originally Posted by NeilBlanchard

But 6,000 years ago - I doubt it.

Most of the Sahara was green between 6 and 7000 years ago.

Nubia is in the Eastern Sahara and was a major kingdom "7000 years ago" - BBC video series about it starts here.

http://www.youtube.com/watch?v=tp6P_hBnF1s

Jump to 8 minutes in and the local guide / historian shows ancient paintings of cattle made 5000-6000BC and only discovered about 2 years ago.

Jump to 9:15 in and the local guy explains it wasn't desert 6000-7000BC. Carry on watching and they explain about the Sahara being green at the time.

EDIT - Start from Part 2 - its quicker

http://www.youtube.com/watch?v=MIDDMGYBEOE

It disappeared due to "Catestrophic Climate Change".

[jamesqf]

Not even 6000 years ago. Even in Roman times, the northern part was much more fertile, and supplied grain to Rome. Same was true of most of the Mediterranean/mideastern "Cradle of Civilization". It was in large part humans (and their goats) that turned it into desert.

Even then, the observant realized what was happening:

The consequence is, that in comparison of what then was, there are remaining only the bones of the wasted body, as they may be called, as in the case of small islands, all the richer and softer parts of the soil having fallen away, and the mere skeleton of the land being left. But in the primitive state of the country, its mountains were high hills covered with soil, and the plains, as they are termed by us, of Phelleus were full of rich earth, and there was abundance of wood in the mountains. Of this last the traces still remain, for although some of the mountains now only afford sustenance to bees, not so very long ago there were still to be seen roofs of timber cut from trees growing there, which were of a size sufficient to cover the largest houses; and there were many other high trees, cultivated by man and bearing abundance of food for cattle. Moreover, the land reaped the benefit of the annual rainfall, not as now losing the water which flows off the bare earth into the sea, but, having an abundant supply in all places, and receiving it into herself and treasuring it up in the close clay soil, it let off into the hollows the streams which it absorbed from the heights, providing everywhere abundant fountains and rivers, of which there may still be observed sacred memorials in places where fountains once existed; and this proves the truth of what I am saying.

Plato, Critias ca 400 BC

[freebeard]

6K? 60K? Within human memory for sure, there's those petroglyphs, not to mention Ozymandias by Shelley.

In any case, I see the link I snagged from Google is to the Finnish Wikipedia page. For some reason there is no English page on Saharasia. It is more about patriarchy than climate, but the official page is at:

James DeMeo, Saharasia

Rebuttal (the Taureg are counterfactual) at:

Flaws of the Saharasia Hypothesis of James DeMeo

I don't have a link, but something I saw recently suggested the Sahara was wet prior to 6K years ago, but dry prior to 11K years ago.

As for the 2nd heresy, I'd have to watch it again.

Edit: I now see the intervening posts. It wasn't just the Sahara—look at any color picture of the whole Earth's surface. It extends all the way to the Gobi Desert.

Originally Posted by jamesqf

It was in large part humans (and their goats) that turned it into desert.

My friend says cattle. I say nuclear weapons; and I cite Sodom, Gomorrah, the Ramayana and the Mahabharata. And Robert Oppenheimer.

[Arragonis]

Originally Posted by jamesqf

Even then, the observant realized what was happening: Plato, Critias ca 400 BC

I don't think he was writing about the same area, but it isn't clear. The full text is here, the section quoted is :

Now the country was inhabited in those days by various classes of
citizens;-there were artisans, and there were husbandmen, and there
was also a warrior class originally set apart by divine men. The
latter dwelt by themselves, and had all things suitable for nurture
and education; neither had any of them anything of their own, but they
regarded all that they had as common property; nor did they claim to
receive of the other citizens anything more than their necessary food.
And they practised all the pursuits which we yesterday described as
those of our imaginary guardians. Concerning the country the
Egyptian priests said what is not only probable but manifestly true,
that the boundaries were in those days fixed by the Isthmus, and
that in the direction of the continent they extended as far as the
heights of Cithaeron and Parnes; the boundary line came down in the
direction of the sea, having the district of Oropus on the right,
and with the river Asopus as the limit on the left. The land was the
best in the world, and was therefore able in those days to support a
vast army, raised from the surrounding people. Even the remnant of
Attica which now exists may compare with any region in the world for
the variety and excellence of its fruits and the suitableness of its
pastures to every sort of animal, which proves what I am saying; but
in those days the country was fair as now and yielded far more
abundant produce. How shall I establish my words? and what part of
it can be truly called a remnant of the land that then was? The
whole country is only a long promontory extending far into the sea
away from the rest of the continent, while the surrounding basin of
the sea is everywhere deep in the neighbourhood of the shore. Many
great deluges have taken place during the nine thousand years, for
that is the number of years which have elapsed since the time of which
I am speaking; and during all this time and through so many changes,
there has never been any considerable accumulation of the soil
coming down from the mountains, as in other places, but the earth
has fallen away all round and sunk out of sight. The consequence is,
that in comparison of what then was, there are remaining only the
bones of the wasted body, as they may be called, as in the case of
small islands, all the richer and softer parts of the soil having
fallen away, and the mere skeleton of the land being left. But in
the primitive state of the country, its mountains were high hills
covered with soil, and the plains, as they are termed by us, of
Phelleus were full of rich earth, and there was abundance of wood in
the mountains. Of this last the traces still remain, for although some
of the mountains now only afford sustenance to bees, not so very
long ago there were still to be seen roofs of timber cut from trees
growing there, which were of a size sufficient to cover the largest
houses; and there were many other high trees, cultivated by man and
bearing abundance of food for cattle. Moreover, the land reaped the
benefit of the annual rainfall, not as now losing the water which
flows off the bare earth into the sea, but, having an abundant
supply in all places, and receiving it into herself and treasuring
it up in the close clay soil, it let off into the hollows the
streams which it absorbed from the heights, providing everywhere
abundant fountains and rivers, of which there may still be observed
sacred memorials in places where fountains once existed; and this
proves the truth of what I am saying.

Oropus is in Greece just north of Athens. Attica is the region of Greece around Athens. Cithaeron (Kithairon) is in central Greece, Parnes (Parnitha) is a mountain range in Northern Greence.

The description of a bit of land sticking out into the sea and the small Islands would match the general shape of Greece and its surroundings.

The text is quite "dense", as in hard to interpret though - so this could be incorrect.

[Arragonis]

Originally Posted by jamesqf

It was in large part humans (and their goats) that turned it into desert.

Linky please.

The historian in the videos above stated "catastrophic climate change" as the reason which must have been a natural change in the climate for some reason or other.

It is not impossible that humans did cause or accelerate it - they did (arguably) accelerate the catastrophic soil erosion that destroyed a complete civilisation in South America by cutting down the specific trees that held the soil together in the search for larger areas of farmland.

[Arragonis]

Third post - this part

Now the country was inhabited in those days by various classes of
citizens;-there were artisans, and there were husbandmen, and there
was also a warrior class originally set apart by divine men. The
latter dwelt by themselves, and had all things suitable for nurture
and education; neither had any of them anything of their own, but they
regarded all that they had as common property;

Could relate to the seperate "city state" of Sparta which coexisted with Greece at the time - they did regard property as communal and relied on slaves to produce all they needed.

[freebeard]

Plato notwithstanding, it looks to me like someone said, "Nuke it from orbit. It's the only way to be sure."

First Edit -- I shouldn't put it on anyone else to do it, so I listened to Freeman Dyson again. His 2nd heresy, at 10:52 (he touches on abiotic oil at 7:20), is titled Land use and Climate. He asserts that 1/10" of new topsoil (averaged over all the arable land on the planet) would sequester all the carbon emitted into the atmosphere year on year.

Is he saying that carbon dioxide is not a greenhouse gas?

His assertion there is that CO2 has more effect in cool, dry air than in moist hot air so the cool parts get warmer, but the warm part don't get hotter

I recommend the whole talk.

He puts his head down and plows through the words, but you can put Settings on 1.5x speed and save a few minutes.

[NeilBlanchard]

Insulation works no matter what the temperature.

[Arragonis]

Originally Posted by freebeard

His assertion there is that CO2 has more effect in cool, dry air than in moist hot air so the cool parts get warmer, but the warm part don't get hotter

Thats part of the standard theory of AGW - the warmer and wetter areas don't warm as fast as the colder ones.

[freebeard]

That's where he touched on NeilBlanchard's question. The 'heresy' is generally that manmade change in atmospheric CO2 could be countered by 1/10" of topsoil, averaged.

Originally Posted by NeilBlanchard

Insulation works no matter what the temperature.

"His assertion [there] is that CO2 has more effect in cool, dry air than in moist hot air" relative to the effect from the water vapor.

Sorry.