Sunday, January 16, 2011

Not Your Average Carbon Footprint

Roman rise and fall 'recorded in trees'

"An extensive study of tree growth rings says there could be a link between the rise and fall of past civilisations and sudden shifts in Europe's climate.
A team of researchers based their findings on data from 9,000 wooden artifacts from the past 2,500 years.
They found that periods of warm, wet summers coincided with prosperity, while political turmoil occurred during times of climate instability.
The findings have been
published online by the journal Science.
"Looking back on 2,500 years, there are examples where climate change impacted human history," co-author Ulf Buntgen, a paleoclimatologist at the Swiss Federal Research Institute for Forest, Snow and Landscape, told the Science website.
The team capitalised on a system used to date material unearthed during excavations.
Distinct drying in the 3rd Century paralleled a period of serious crisis in the western Roman empire
"Archaeologists have developed oak ring width chronologies from Central Europe that cover nearly the entire Holocene and have used them for the purpose of dating artefacts, historical buildings, antique artwork and furniture," they wrote.
"Chronologies of living and relict oaks may reflect distinct patterns of summer precipitation and drought."
The team looked at how weather over the past couple of centuries affected living trees' growth rings.
During good growing seasons, when water and nutrients are in plentiful supply, trees form broad rings, with their boundaries relatively far apart.
But in unfavourable conditions, such as drought, the rings grow in much tighter formation.
The researchers then used this data to reconstruct annual weather patterns from the growth rings preserved in the artefacts.
Once they had developed a chronology stretching back over the past 2,500 years, they identified a link with prosperity levels in past societies, such as the Roman Empire."

Although this is fine and jim dandy and makes sense it can also be viewed as jumping on the political climate change bandwagon. It's no sudden revelation that dendrochronology gives good indications of climate variations. The larger picture should always include possible reasons for those instabilities, and while we're all hung up these days about man made climate change or no there's good evidence that celestial mega events played a huge part in altering climate, including disasters that may have ended Rome.

The day the sky fell in - A metallic asteroid may have coincided with the fall of Rome, says Duncan Steel

"Pescara is on the Adriatic coast, located across the Italian peninsula from Rome. Housed there is the International Research School of Planetary Sciences, where staff and students study topics ranging from planetary geology to astrobiology. In 1999, a young impact cratering specialist from Sweden, Jens Ormö, arrived to take up a three-year position funded by the European Union.
Ormö, it happens, is keen on hill walking, and just inland from Pescara are some of the most spectacular mountains in the Apennines. He decided that some hiking in the area of the Sirente Massif was in order, and so he consulted a local guidebook. As he thumbed its pages, Ormö came across a photograph of something that amazed him. What he saw, labelled as a natural lake, was surely an impact crater.
An expedition to the site of the putative impact, on the Sirente plain, was hastily organised. Colleagues confirmed Ormö's initial suspicion. Here was an impact crater about 140 metres wide, previously unrecognised despite lying only a short distance from a busy road, and visible from miles away. It has appeared on maps for centuries, and in guidebooks for decades - but no one had recognised its significance.
Natural lakes are common in the area. But this one has a raised rim, now about two metres high, but originally rather thicker. This was produced by the asteroid throwing material out from the impact zone, as it crashed at a speed of around 20km per second, producing a huge explosion. Later filled with rainwater, the crater is now only a few metres deep, and occasionally dries up during hot summers. But it was more than 30 metres to the bottom when first formed. Centuries of weathering has eroded its bank and gradually filled it in.
Relatively modest craters like this are unusual, because small asteroids can only reach the ground intact if they are metallic, and thus strong enough to withstand the physical shock of slamming into the atmosphere at such speeds. The best guess at present is that the asteroid was about 10 metres across, and had a composition similar to nickel-iron."

It seems this surviving crater was part of a much more massive object, or more likely a constellation of numerous objects that impacted:

"Confirmation of the impact origin comes from 17 smaller craters, typically 10 metres wide, scattered around the Sirente plain. These are due to fragments of the asteroid that separated in flight through the atmosphere. A magnetic survey shows that most are associated with anomalously high fields, indicating sub-surface metallic lumps."

"...three British cometary astrophysicists - Mark Bailey, Victor Clube, and Bill Napier - had published a highly relevant paper in 1990. They wrote that Earth had been at increased risk of bombardment by cometary debris in the period A.D. 400-600. They based their conclusion on the increased number of great meteor showers during that period. The danger in A.D. 400-600, concluded Bailey and colleagues, was of Earth running into a "cosmic swarm" of objects the size of the one that exploded over Tunguska, Siberia, in 1908." Exodus to Arthur: Catastrophic Encounters With Comets

It's pretty likely that there was a massive bombardment around the time of Rome's demise which created climate havoc which is evidenced in the tree rings. It was the coup de gras for an already beleaguered civilization. The problems of recognizing that correlation until recently was first the denial that any rocks could fall from the sky and scientific reluctance to recognize astronomical catastrophism as a viable reason for widespread societal upheaval. Earth probably caught shit at least three times in the past 5,000 years and more than likely five times, changing history with each shellacking.

The final squish


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