Posted on 12/18/2008 8:57:54 AM PST by Red Badger
The power of viruses is well documented in human history. Swarms of little viral Davids have repeatedly laid low the great Goliaths of human civilization, most famously in the devastating pandemics that swept the New World during European conquest and settlement.
In recent years, there has been growing evidence for the hypothesis that the effect of the pandemics in the Americas wasn't confined to killing indigenous peoples. Global climate appears to have been altered as well.
Stanford University researchers have conducted a comprehensive analysis of data detailing the amount of charcoal contained in soils and lake sediments at the sites of both pre-Columbian population centers in the Americas and in sparsely populated surrounding regions. They concluded that reforestation of agricultural lands-abandoned as the population collapsed-pulled so much carbon out of the atmosphere that it helped trigger a period of global cooling, at its most intense from approximately 1500 to 1750, known as the Little Ice Age.
"We estimate that the amount of carbon sequestered in the growing forests was about 10 to 50 percent of the total carbon that would have needed to come out of the atmosphere and oceans at that time to account for the observed changes in carbon dioxide concentrations," said Richard Nevle, visiting scholar in the Department of Geological and Environmental Sciences at Stanford. Nevle and Dennis Bird, professor in geological and environmental sciences, presented their study at the annual meeting of the American Geophysical Union on Dec. 17, 2008.
Nevle and Bird synthesized published data from charcoal records from 15 sediment cores extracted from lakes, soil samples from 17 population centers and 18 sites from the surrounding areas in Central and South America. They examined samples dating back 5,000 years.
What they found was a record of slowly increasing charcoal deposits, indicating increasing burning of forestland to convert it to cropland, as agricultural practices spread among the human population-until around 500 years ago: At that point, there was a precipitous drop in the amount of charcoal in the samples, coinciding with the precipitous drop in the human population in the Americas.
To verify their results, they checked their fire histories based on the charcoal data against records of carbon dioxide concentrations and carbon isotope ratios that were available.
"We looked at ice cores and tropical sponge records, which give us reliable proxies for the carbon isotope composition of atmospheric carbon dioxide. And it jumped out at us right away," Nevle said. "We saw a conspicuous increase in the isotope ratio of heavy carbon to light carbon. That gave us a sense that maybe we were looking at the right thing, because that is exactly what you would expect from reforestation."
During photosynthesis, plants prefer carbon dioxide containing the lighter isotope of carbon. Thus a massive reforestation event would not only decrease the amount of carbon dioxide in the atmosphere, but would also leave carbon dioxide in the atmosphere that was enriched in the heavy carbon isotope.
Other theories have been proposed to account for the cooling at the time of the Little Ice Age, as well as the anomalies in the concentration and carbon isotope ratios of atmospheric carbon dioxide associated with that period.
Variations in the amount of sunlight striking the Earth, caused by a drop in sunspot activity, could also be a factor in cooling down the globe, as could a flurry of volcanic activity in the late 16th century.
But the timing of these events doesn't fit with the observed onset of the carbon dioxide drop. These events don't begin until at least a century after carbon dioxide in the atmosphere began to decline and the ratio of heavy to light carbon isotopes in atmospheric carbon dioxide begins to increase.
Nevle and Bird don't attribute all of the cooling during the Little Ice Age to reforestation in the Americas.
"There are other causes at play," Nevle said. "But reforestation is certainly a first-order contributor."
Didn’t some scientist pretty much prove, the “little ice age” in question was a direct result of a massive supervolcanic eruption of Krakatoa in Indonesia, which wiped out agriculture around the planet?...
Or was that another little ice age?
Is this winter a little ice age?...
Homosexual behavior among animals occurs under conditions of overcrowding. Apparently, stress on the female animals causes changes in the hormones of their newborn which subsequently have an influence on their offspring. Probably happens in humans too. Whatever happened to the idea of protecting pregnant women from stress?
Regarding the Little Ice Age, how do these data correlate with the missing sunspots of the Maunder Minimum? There may have been an additive effect.
Actually, the change coming after 1500, makes sense. The Spaniards introduced European diseases like measles and smallpox which may have eliminated as much as 4/5ths of the Aztec, Maya, and Inca populations, as well as others that they had contact with. It is estimated that in North America the indigenous population was at least 20 million before northern Europeans brought in their diseases.
Of course, they returned the favor by giving syphilis to the returning Spaniards. Also the potato. ;-)
are these ‘scientists’ suggesting that the way to stop global warming is to reduce population?
Couldn’t hurt, might even do some good. By non-violent, voluntary means, of course. Certainly would help gas and food prices.
I have heard the figure of 1 billion, if they are going to have American and European standard of living.
I get the feeling that the researchers started out with a conclusion already in mind, and looked for research to support it. Which is the worst kind of scientific research.
Was that much land under cultivation in the Americas? Nearly all Indian tribes were hunter-gatherers and had no cultivated land at all.
I hope the “Warmers” have a contingency plan to put carbon BACK into the atmosphere should we begin to rapidly cool.
Right now, they’re playing with disaster.
As one of my old taglines says: Al carbon in all that oil, coal and natural gas was once in the atmosphere. We're just putting it back.............
Eastern and Southern Indian tribes were cultivators, a slash and burn type of agriculture..........
If he did, he was a Krak-Pot, since the volcano's famous eruption happened in 1883......
Crickets!
Ever seen when they do their mating ritual in the Fall?
Smells like ass.
Deforrestation was naturally occuring due to forest fires caused by lightning strikes. But in order to keep the grant money coming in, ya gotta find a way to blame it on man..........Because without a man made problem, you can't finance a man made solution.......
I think maybe the scientist’s conclusion was that Krakatoa initiated what we consider the dark ages, it wasn’t so recent as the “little ice age” in the top article.
The supposition was something like this:
First off, he went to some length to determine the date of a massive eruption at Krakatoa - I think it was around 500 AD. The resulting mess of particulates in the atmosphere actually darkened the sky around the globe for several years - and dropped average temperatures.
Crops were seriously impacted, which brought economic hardship, leading to social chaos and eventual ruin.
It probably seems a bit like Coast to Coast AM fare, but the supposition was pretty well supported. Wish I remembered more details.
It was on one of those Discovery channel, or PBS specials where they walk through a series of scientific discoveries to an interesting scientific conclusion about history - not like the global warming nonsense, but real science.
Like another - a fjord in Alaska which was for a long time known to have somehow suffered periodic 100-yard high tsunamis for unknown reasons, which eventually was determined to have been caused by massive rock slides from a cliff at the foot of the fjord, which dropped tons of rock thousands of feet into the water of the fjord, generating a terrible wave.
It’s like the Bermuda Triangle hypothesis, that the cause is vast Methane deposits under the steep sedimentary seabed under that part of the Atlantic - which when released by undersea slides of that sedimentary mud, can remove bouyancy from the sea and actually sink huge ships - and change the oxygen mix of the air above enough to cause internal combustion airplane engines to cease operation. Thus explaining the mysterious disappearance of planes and ships in the area.
It just made abundant sense at the time. I bought the idea anyway.
> Regarding the Little Ice Age, how do these data correlate with the missing sunspots of the Maunder Minimum?
That was the original correlation I believe — Galileo and others discovered and kept counts of sunspots, and that was during the LIA. :’)
> Homosexual behavior among animals occurs under conditions of overcrowding.
Uh, okay. :’)
slash and burn type of agriculture...
Another thing the indians did in the east was burn areas to turn them into grasslands which were used by buffalo. The Shenandoah Valley was once a buffalo common, and after the settlers there drove them away they continued to use areas in Kentucky, especially north of the Green River and Mammoth Cave. It was called the barrens and was quite large.
Indians used to set forest fires frequently. Deer and other wildlife live at the interface between forest and meadow, so the ideal hunting environment is forest pockmarked by many fire-caused meadows.
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