Climatologists - China's T'ang Dynasty - Summit Of Classic Period - Destroyed By Climate - AFP

[hatrack]

EDIT

Scientists led by Gerald Haug of the Geoforschungszentrum (GFZ) in Potsdam, eastern Germany, looked at sedimentary cores taken from a lake at Zhanjiang in coastal southeastern China, opposite the tropical island of Hainan. The magnetic properties and content of titanium in these deposits are an indicator of the strength of the winter cycle in the East Asian monsoon system, they believe.

They found that over the past 15,000 years, there had been three periods in which the winter monsoon was strong but the summer monsoon was weak. The first two periods occurred at key moments during the last Ice Age, while the last ran from around 700 to 900. Each of these monsoon shifts coincided with what was, relative to the climate epoch, unusually cold weather.

The twilight of the Tang began in 751, when the imperial army was defeated by Arabs. But what eventually destroyed the dynasty were prolonged droughts and poor summer rains, which caused crop failure and stoked peasants' uprisings. Eventually, these rebellions led to the collapse of the dynasty in 907.

Haug's team suggests this shift in tropical precipitation occurred on both sides of the Pacific, not just in coastal East Asia. The same migration of the rainband occurred in Central America and doomed the so-called classic period of the Mayan civilisation, at almost exactly the same time as the Tang era, they believe. Comparison of the titanium records from the Huguangyan Lake, in Guangdong province, and from the Cariaco basin, in Venezuela, have thrown up striking similarities. Both suggest a general shift towards a drier climate at around 750 and then, during these generally drier period, three-year cycles in which rainfall was very low.

EDIT

http://www.terradaily.com/2006/070103180024.hhjnjkzr.html

[eppur_se_muova]

1. Our entire civilization is dependent on a few inches of topsoil and regular rains.

Just to put things in perspective.

[Dogmudgeon]

3. And we're destroying the topsoil, too

David Pimentel (hated by the ethanol lobby) is the highest-profile scientist warning about soil depletion. We've blown through more than half the "nutritious" topsoil already, and at current depletion rates, the entire continent of North America could be unable to support more than a few million people by the end of the century ... or earlier. As factory farming has become more efficient, that efficiency has leached the soil dead in some areas. There doesn't seem to be a lot of scientists working on this problem, and they all differ somewhat on the details, but they are nearly all unanimous that our farming practices are destroying the ability of the soil to support plant growth.

Sounds like an old Dead Milkmen song, right? Sadly, this is serious stuff, and it won't be fixed by simply adding ammonium nitrate or getting everybody to rick their own compost heaps. The depletion is proceeding at a tremendous pace; it has also largely escaped notice.

--p!

[GreenPartyVoter]

4. I read not long ago that our food is half as nutritious as that of our g-grandparents. Does this

tie in with the topsoil loss? They were talking abt veggies and grains, not processed foods.

[xchrom]

2. many of the great civilizations

have been irrevocable changed, challenged or destroyed by the enivironment.

the maya, neolithic england, etc.

we had better be paying attention.

the lessons are there to read -- if only we will.

[GreenPartyVoter]

5. I think saliniation of the soil of arable lands is noted in the loss of many cultures, yes?

Is that what happened to ancient babylon's famed gardens?

[xchrom]

6. that and other things.

the mini ice age helped to bring about the ''dark ages'' after the fall of the roman empire.

too many people and bad farming practises effected baylon and the maya.
and so on.

[Dead_Parrot]

7. A lot of that was deliberate, though

Not sure about Babylon, but "salting the earth" is what the Romans did to Carthage, and the Assyrians did to just about everybody. It's an effective way to pull the plug on an enemy state once you've dealt with their army.